diff --git a/bin/configs/ruby-generate-alias-as-model.yaml b/bin/configs/ruby-generate-alias-as-model.yaml
new file mode 100644
index 00000000000..126e1e09483
--- /dev/null
+++ b/bin/configs/ruby-generate-alias-as-model.yaml
@@ -0,0 +1,12 @@
+generatorName: ruby
+outputDir: samples/openapi3/client/features/generate-alias-as-model/ruby-client/
+library: typhoeus
+inputSpec: modules/openapi-generator/src/test/resources/3_0/features/generate-alias-as-model.yaml
+templateDir: modules/openapi-generator/src/main/resources/ruby-client
+additionalProperties:
+  gemVersion: 1.0.0
+  moduleName: Petstore
+  gemName: petstore
+  skipFormModel: "true"
+strictSpecBehavior: false
+generateAliasAsModel: true
diff --git a/docs/generators/ruby-on-rails.md b/docs/generators/ruby-on-rails.md
index 550afc7e0e5..ec34e9afdde 100644
--- a/docs/generators/ruby-on-rails.md
+++ b/docs/generators/ruby-on-rails.md
@@ -34,6 +34,9 @@ sidebar_label: ruby-on-rails
 
 | Type/Alias | Instantiated By |
 | ---------- | --------------- |
+|array|Array|
+|map|Hash|
+|set|Set|
 
 
 ## LANGUAGE PRIMITIVES
diff --git a/docs/generators/ruby-sinatra.md b/docs/generators/ruby-sinatra.md
index b9568cc41c4..ea23b05175f 100644
--- a/docs/generators/ruby-sinatra.md
+++ b/docs/generators/ruby-sinatra.md
@@ -33,6 +33,9 @@ sidebar_label: ruby-sinatra
 
 | Type/Alias | Instantiated By |
 | ---------- | --------------- |
+|array|Array|
+|map|Hash|
+|set|Set|
 
 
 ## LANGUAGE PRIMITIVES
diff --git a/docs/generators/ruby.md b/docs/generators/ruby.md
index 59886616030..36fbb360363 100644
--- a/docs/generators/ruby.md
+++ b/docs/generators/ruby.md
@@ -35,6 +35,9 @@ sidebar_label: ruby
 
 | Type/Alias | Instantiated By |
 | ---------- | --------------- |
+|array|Array|
+|map|Hash|
+|set|Set|
 
 
 ## LANGUAGE PRIMITIVES
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractRubyCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractRubyCodegen.java
index a2a7d460af6..0ffe7c89566 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractRubyCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractRubyCodegen.java
@@ -86,6 +86,10 @@ abstract public class AbstractRubyCodegen extends DefaultCodegen implements Code
         typeMapping.put("ByteArray", "String");
         typeMapping.put("UUID", "String");
         typeMapping.put("URI", "String");
+
+        instantiationTypes.put("map", "Hash");
+        instantiationTypes.put("array", "Array");
+        instantiationTypes.put("set", "Set");
     }
 
     @Override
@@ -118,6 +122,22 @@ abstract public class AbstractRubyCodegen extends DefaultCodegen implements Code
         return super.getTypeDeclaration(schema);
     }
 
+    @Override
+    public String toInstantiationType(Schema schema) {
+        if (ModelUtils.isMapSchema(schema)) {
+            return instantiationTypes.get("map");
+        } else if (ModelUtils.isArraySchema(schema)) {
+            String parentType;
+            if (ModelUtils.isSet(schema)) {
+                parentType = "set";
+            } else {
+                parentType = "array";
+            }
+            return instantiationTypes.get(parentType);
+        }
+        return super.toInstantiationType(schema);
+    }
+
     @Override
     public String toDefaultValue(Schema p) {
         if (ModelUtils.isIntegerSchema(p) || ModelUtils.isNumberSchema(p) || ModelUtils.isBooleanSchema(p)) {
diff --git a/modules/openapi-generator/src/test/resources/3_0/features/generate-alias-as-model.yaml b/modules/openapi-generator/src/test/resources/3_0/features/generate-alias-as-model.yaml
new file mode 100644
index 00000000000..7381affa858
--- /dev/null
+++ b/modules/openapi-generator/src/test/resources/3_0/features/generate-alias-as-model.yaml
@@ -0,0 +1,65 @@
+openapi: 3.0.0
+info:
+  description: This specification shows how to generate aliases to maps and arrays as models.
+  version: 1.0.0
+  title: OpenAPI Extension generating aliases to maps and arrays as models
+  license:
+    name: Apache-2.0
+    url: 'https://www.apache.org/licenses/LICENSE-2.0.html'
+tags:
+  - name: usage
+    description: Show usage of x-generate-alias-as-model extension
+servers:
+  - url: 'http://petstore.swagger.io/v2'
+    description: petstore server
+paths:
+  /map:
+    get:
+      tags:
+        - usage
+      summary: Use alias to map
+      description: Use alias to map
+      operationId: map
+      requestBody:
+        content:
+          "application/json":
+            schema:
+              $ref: "#/components/schemas/MapAlias"
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                type: object
+  /array:
+    get:
+      tags:
+        - usage
+      summary: Use alias to array
+      description: Use alias to array
+      operationId: array
+      requestBody:
+        content:
+          "application/json":
+            schema:
+              $ref: "#/components/schemas/ArrayAlias"
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                type: object
+
+components:
+  schemas:
+    ArrayAlias:
+      type: array
+      items:
+        type: integer
+
+    MapAlias:
+      type: object
+      additionalProperties:
+        type: string
\ No newline at end of file
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.gitignore b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.gitignore
new file mode 100644
index 00000000000..05a17cb8f0a
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.gitignore
@@ -0,0 +1,39 @@
+# Generated by: https://openapi-generator.tech
+#
+
+*.gem
+*.rbc
+/.config
+/coverage/
+/InstalledFiles
+/pkg/
+/spec/reports/
+/spec/examples.txt
+/test/tmp/
+/test/version_tmp/
+/tmp/
+
+## Specific to RubyMotion:
+.dat*
+.repl_history
+build/
+
+## Documentation cache and generated files:
+/.yardoc/
+/_yardoc/
+/doc/
+/rdoc/
+
+## Environment normalization:
+/.bundle/
+/vendor/bundle
+/lib/bundler/man/
+
+# for a library or gem, you might want to ignore these files since the code is
+# intended to run in multiple environments; otherwise, check them in:
+# Gemfile.lock
+# .ruby-version
+# .ruby-gemset
+
+# unless supporting rvm < 1.11.0 or doing something fancy, ignore this:
+.rvmrc
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.openapi-generator-ignore b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.openapi-generator-ignore
new file mode 100644
index 00000000000..7484ee590a3
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.openapi-generator-ignore
@@ -0,0 +1,23 @@
+# OpenAPI Generator Ignore
+# Generated by openapi-generator https://github.com/openapitools/openapi-generator
+
+# Use this file to prevent files from being overwritten by the generator.
+# The patterns follow closely to .gitignore or .dockerignore.
+
+# As an example, the C# client generator defines ApiClient.cs.
+# You can make changes and tell OpenAPI Generator to ignore just this file by uncommenting the following line:
+#ApiClient.cs
+
+# You can match any string of characters against a directory, file or extension with a single asterisk (*):
+#foo/*/qux
+# The above matches foo/bar/qux and foo/baz/qux, but not foo/bar/baz/qux
+
+# You can recursively match patterns against a directory, file or extension with a double asterisk (**):
+#foo/**/qux
+# This matches foo/bar/qux, foo/baz/qux, and foo/bar/baz/qux
+
+# You can also negate patterns with an exclamation (!).
+# For example, you can ignore all files in a docs folder with the file extension .md:
+#docs/*.md
+# Then explicitly reverse the ignore rule for a single file:
+#!docs/README.md
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.openapi-generator/FILES b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.openapi-generator/FILES
new file mode 100644
index 00000000000..6599ee36fec
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.openapi-generator/FILES
@@ -0,0 +1,24 @@
+.gitignore
+.rspec
+.rubocop.yml
+.travis.yml
+Gemfile
+README.md
+Rakefile
+docs/ArrayAlias.md
+docs/MapAlias.md
+docs/UsageApi.md
+git_push.sh
+lib/petstore.rb
+lib/petstore/api/usage_api.rb
+lib/petstore/api_client.rb
+lib/petstore/api_error.rb
+lib/petstore/configuration.rb
+lib/petstore/configuration.rb
+lib/petstore/models/array_alias.rb
+lib/petstore/models/map_alias.rb
+lib/petstore/version.rb
+petstore.gemspec
+spec/api_client_spec.rb
+spec/configuration_spec.rb
+spec/spec_helper.rb
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.openapi-generator/VERSION b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.openapi-generator/VERSION
new file mode 100644
index 00000000000..d99e7162d01
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.openapi-generator/VERSION
@@ -0,0 +1 @@
+5.0.0-SNAPSHOT
\ No newline at end of file
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.rspec b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.rspec
new file mode 100644
index 00000000000..83e16f80447
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.rspec
@@ -0,0 +1,2 @@
+--color
+--require spec_helper
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.rubocop.yml b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.rubocop.yml
new file mode 100644
index 00000000000..d32b2b1cdab
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.rubocop.yml
@@ -0,0 +1,148 @@
+# This file is based on https://github.com/rails/rails/blob/master/.rubocop.yml (MIT license)
+# Automatically generated by OpenAPI Generator (https://openapi-generator.tech)
+AllCops:
+  TargetRubyVersion: 2.4
+  # RuboCop has a bunch of cops enabled by default. This setting tells RuboCop
+  # to ignore them, so only the ones explicitly set in this file are enabled.
+  DisabledByDefault: true
+  Exclude:
+    - '**/templates/**/*'
+    - '**/vendor/**/*'
+    - 'actionpack/lib/action_dispatch/journey/parser.rb'
+
+# Prefer &&/|| over and/or.
+Style/AndOr:
+  Enabled: true
+
+# Align `when` with `case`.
+Layout/CaseIndentation:
+  Enabled: true
+
+# Align comments with method definitions.
+Layout/CommentIndentation:
+  Enabled: true
+
+Layout/ElseAlignment:
+  Enabled: true
+
+Layout/EmptyLineAfterMagicComment:
+  Enabled: true
+
+# In a regular class definition, no empty lines around the body.
+Layout/EmptyLinesAroundClassBody:
+  Enabled: true
+
+# In a regular method definition, no empty lines around the body.
+Layout/EmptyLinesAroundMethodBody:
+  Enabled: true
+
+# In a regular module definition, no empty lines around the body.
+Layout/EmptyLinesAroundModuleBody:
+  Enabled: true
+
+Layout/FirstArgumentIndentation:
+  Enabled: true
+
+# Use Ruby >= 1.9 syntax for hashes. Prefer { a: :b } over { :a => :b }.
+Style/HashSyntax:
+  Enabled: false
+
+# Method definitions after `private` or `protected` isolated calls need one
+# extra level of indentation.
+Layout/IndentationConsistency:
+  Enabled: true
+  EnforcedStyle: indented_internal_methods
+
+# Two spaces, no tabs (for indentation).
+Layout/IndentationWidth:
+  Enabled: true
+
+Layout/LeadingCommentSpace:
+  Enabled: true
+
+Layout/SpaceAfterColon:
+  Enabled: true
+
+Layout/SpaceAfterComma:
+  Enabled: true
+
+Layout/SpaceAroundEqualsInParameterDefault:
+  Enabled: true
+
+Layout/SpaceAroundKeyword:
+  Enabled: true
+
+Layout/SpaceAroundOperators:
+  Enabled: true
+
+Layout/SpaceBeforeComma:
+    Enabled: true
+
+Layout/SpaceBeforeFirstArg:
+    Enabled: true
+
+Style/DefWithParentheses:
+  Enabled: true
+
+# Defining a method with parameters needs parentheses.
+Style/MethodDefParentheses:
+  Enabled: true
+
+Style/FrozenStringLiteralComment:
+  Enabled: false
+  EnforcedStyle: always
+
+# Use `foo {}` not `foo{}`.
+Layout/SpaceBeforeBlockBraces:
+  Enabled: true
+
+# Use `foo { bar }` not `foo {bar}`.
+Layout/SpaceInsideBlockBraces:
+  Enabled: true
+
+# Use `{ a: 1 }` not `{a:1}`.
+Layout/SpaceInsideHashLiteralBraces:
+  Enabled: true
+
+Layout/SpaceInsideParens:
+  Enabled: true
+
+# Check quotes usage according to lint rule below.
+#Style/StringLiterals:
+#  Enabled: true
+#  EnforcedStyle: single_quotes
+
+# Detect hard tabs, no hard tabs.
+Layout/IndentationStyle:
+  Enabled: true
+
+# Blank lines should not have any spaces.
+Layout/TrailingEmptyLines:
+  Enabled: true
+
+# No trailing whitespace.
+Layout/TrailingWhitespace:
+  Enabled: false
+
+# Use quotes for string literals when they are enough.
+Style/RedundantPercentQ:
+  Enabled: true
+
+# Align `end` with the matching keyword or starting expression except for
+# assignments, where it should be aligned with the LHS.
+Layout/EndAlignment:
+  Enabled: true
+  EnforcedStyleAlignWith: variable
+  AutoCorrect: true
+
+# Use my_method(my_arg) not my_method( my_arg ) or my_method my_arg.
+Lint/RequireParentheses:
+  Enabled: true
+
+Style/RedundantReturn:
+  Enabled: true
+  AllowMultipleReturnValues: true
+
+Style/Semicolon:
+  Enabled: true
+  AllowAsExpressionSeparator: true
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.travis.yml b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.travis.yml
new file mode 100644
index 00000000000..d2d526df594
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/.travis.yml
@@ -0,0 +1,11 @@
+language: ruby
+cache: bundler
+rvm:
+  - 2.3
+  - 2.4
+  - 2.5
+script:
+  - bundle install --path vendor/bundle
+  - bundle exec rspec
+  - gem build petstore.gemspec
+  - gem install ./petstore-1.0.0.gem
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/Gemfile b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/Gemfile
new file mode 100644
index 00000000000..c2e3127cdcf
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/Gemfile
@@ -0,0 +1,9 @@
+source 'https://rubygems.org'
+
+gemspec
+
+group :development, :test do
+  gem 'rake', '~> 13.0.1'
+  gem 'pry-byebug'
+  gem 'rubocop', '~> 0.66.0'
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/README.md b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/README.md
new file mode 100644
index 00000000000..99902ebafff
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/README.md
@@ -0,0 +1,93 @@
+# petstore
+
+Petstore - the Ruby gem for the OpenAPI Extension generating aliases to maps and arrays as models
+
+This specification shows how to generate aliases to maps and arrays as models.
+
+This SDK is automatically generated by the [OpenAPI Generator](https://openapi-generator.tech) project:
+
+- API version: 1.0.0
+- Package version: 1.0.0
+- Build package: org.openapitools.codegen.languages.RubyClientCodegen
+
+## Installation
+
+### Build a gem
+
+To build the Ruby code into a gem:
+
+```shell
+gem build petstore.gemspec
+```
+
+Then either install the gem locally:
+
+```shell
+gem install ./petstore-1.0.0.gem
+```
+
+(for development, run `gem install --dev ./petstore-1.0.0.gem` to install the development dependencies)
+
+or publish the gem to a gem hosting service, e.g. [RubyGems](https://rubygems.org/).
+
+Finally add this to the Gemfile:
+
+    gem 'petstore', '~> 1.0.0'
+
+### Install from Git
+
+If the Ruby gem is hosted at a git repository: https://github.com/GIT_USER_ID/GIT_REPO_ID, then add the following in the Gemfile:
+
+    gem 'petstore', :git => 'https://github.com/GIT_USER_ID/GIT_REPO_ID.git'
+
+### Include the Ruby code directly
+
+Include the Ruby code directly using `-I` as follows:
+
+```shell
+ruby -Ilib script.rb
+```
+
+## Getting Started
+
+Please follow the [installation](#installation) procedure and then run the following code:
+
+```ruby
+# Load the gem
+require 'petstore'
+
+api_instance = Petstore::UsageApi.new
+opts = {
+  array_alias: Petstore::ArrayAlias.new # ArrayAlias | 
+}
+
+begin
+  #Use alias to array
+  result = api_instance.array(opts)
+  p result
+rescue Petstore::ApiError => e
+  puts "Exception when calling UsageApi->array: #{e}"
+end
+
+```
+
+## Documentation for API Endpoints
+
+All URIs are relative to *http://petstore.swagger.io/v2*
+
+Class | Method | HTTP request | Description
+------------ | ------------- | ------------- | -------------
+*Petstore::UsageApi* | [**array**](docs/UsageApi.md#array) | **GET** /array | Use alias to array
+*Petstore::UsageApi* | [**map**](docs/UsageApi.md#map) | **GET** /map | Use alias to map
+
+
+## Documentation for Models
+
+ - [Petstore::ArrayAlias](docs/ArrayAlias.md)
+ - [Petstore::MapAlias](docs/MapAlias.md)
+
+
+## Documentation for Authorization
+
+ All endpoints do not require authorization.
+
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/Rakefile b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/Rakefile
new file mode 100644
index 00000000000..c72ca30d454
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/Rakefile
@@ -0,0 +1,10 @@
+require "bundler/gem_tasks"
+
+begin
+  require 'rspec/core/rake_task'
+
+  RSpec::Core::RakeTask.new(:spec)
+  task default: :spec
+rescue LoadError
+  # no rspec available
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/docs/ArrayAlias.md b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/docs/ArrayAlias.md
new file mode 100644
index 00000000000..aaebce0ffe3
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/docs/ArrayAlias.md
@@ -0,0 +1,16 @@
+# Petstore::ArrayAlias
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+
+## Code Sample
+
+```ruby
+require 'Petstore'
+
+instance = Petstore::ArrayAlias.new()
+```
+
+
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/docs/MapAlias.md b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/docs/MapAlias.md
new file mode 100644
index 00000000000..d65a613ff9c
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/docs/MapAlias.md
@@ -0,0 +1,16 @@
+# Petstore::MapAlias
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+
+## Code Sample
+
+```ruby
+require 'Petstore'
+
+instance = Petstore::MapAlias.new()
+```
+
+
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/docs/UsageApi.md b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/docs/UsageApi.md
new file mode 100644
index 00000000000..b1fa34ab7d6
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/docs/UsageApi.md
@@ -0,0 +1,108 @@
+# Petstore::UsageApi
+
+All URIs are relative to *http://petstore.swagger.io/v2*
+
+Method | HTTP request | Description
+------------- | ------------- | -------------
+[**array**](UsageApi.md#array) | **GET** /array | Use alias to array
+[**map**](UsageApi.md#map) | **GET** /map | Use alias to map
+
+
+
+## array
+
+> Object array(opts)
+
+Use alias to array
+
+Use alias to array
+
+### Example
+
+```ruby
+# load the gem
+require 'petstore'
+
+api_instance = Petstore::UsageApi.new
+opts = {
+  array_alias: Petstore::ArrayAlias.new # ArrayAlias | 
+}
+
+begin
+  #Use alias to array
+  result = api_instance.array(opts)
+  p result
+rescue Petstore::ApiError => e
+  puts "Exception when calling UsageApi->array: #{e}"
+end
+```
+
+### Parameters
+
+
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+ **array_alias** | [**ArrayAlias**](ArrayAlias.md)|  | [optional] 
+
+### Return type
+
+**Object**
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
+
+## map
+
+> Object map(opts)
+
+Use alias to map
+
+Use alias to map
+
+### Example
+
+```ruby
+# load the gem
+require 'petstore'
+
+api_instance = Petstore::UsageApi.new
+opts = {
+  map_alias: Petstore::MapAlias.new # MapAlias | 
+}
+
+begin
+  #Use alias to map
+  result = api_instance.map(opts)
+  p result
+rescue Petstore::ApiError => e
+  puts "Exception when calling UsageApi->map: #{e}"
+end
+```
+
+### Parameters
+
+
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+ **map_alias** | [**MapAlias**](MapAlias.md)|  | [optional] 
+
+### Return type
+
+**Object**
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/git_push.sh b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/git_push.sh
new file mode 100644
index 00000000000..ced3be2b0c7
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/git_push.sh
@@ -0,0 +1,58 @@
+#!/bin/sh
+# ref: https://help.github.com/articles/adding-an-existing-project-to-github-using-the-command-line/
+#
+# Usage example: /bin/sh ./git_push.sh wing328 openapi-pestore-perl "minor update" "gitlab.com"
+
+git_user_id=$1
+git_repo_id=$2
+release_note=$3
+git_host=$4
+
+if [ "$git_host" = "" ]; then
+    git_host="github.com"
+    echo "[INFO] No command line input provided. Set \$git_host to $git_host"
+fi
+
+if [ "$git_user_id" = "" ]; then
+    git_user_id="GIT_USER_ID"
+    echo "[INFO] No command line input provided. Set \$git_user_id to $git_user_id"
+fi
+
+if [ "$git_repo_id" = "" ]; then
+    git_repo_id="GIT_REPO_ID"
+    echo "[INFO] No command line input provided. Set \$git_repo_id to $git_repo_id"
+fi
+
+if [ "$release_note" = "" ]; then
+    release_note="Minor update"
+    echo "[INFO] No command line input provided. Set \$release_note to $release_note"
+fi
+
+# Initialize the local directory as a Git repository
+git init
+
+# Adds the files in the local repository and stages them for commit.
+git add .
+
+# Commits the tracked changes and prepares them to be pushed to a remote repository.
+git commit -m "$release_note"
+
+# Sets the new remote
+git_remote=`git remote`
+if [ "$git_remote" = "" ]; then # git remote not defined
+
+    if [ "$GIT_TOKEN" = "" ]; then
+        echo "[INFO] \$GIT_TOKEN (environment variable) is not set. Using the git credential in your environment."
+        git remote add origin https://${git_host}/${git_user_id}/${git_repo_id}.git
+    else
+        git remote add origin https://${git_user_id}:${GIT_TOKEN}@${git_host}/${git_user_id}/${git_repo_id}.git
+    fi
+
+fi
+
+git pull origin master
+
+# Pushes (Forces) the changes in the local repository up to the remote repository
+echo "Git pushing to https://${git_host}/${git_user_id}/${git_repo_id}.git"
+git push origin master 2>&1 | grep -v 'To https'
+
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore.rb
new file mode 100644
index 00000000000..173913b98f6
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore.rb
@@ -0,0 +1,42 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+# Common files
+require 'petstore/api_client'
+require 'petstore/api_error'
+require 'petstore/version'
+require 'petstore/configuration'
+
+# Models
+require 'petstore/models/array_alias'
+require 'petstore/models/map_alias'
+
+# APIs
+require 'petstore/api/usage_api'
+
+module Petstore
+  class << self
+    # Customize default settings for the SDK using block.
+    #   Petstore.configure do |config|
+    #     config.username = "xxx"
+    #     config.password = "xxx"
+    #   end
+    # If no block given, return the default Configuration object.
+    def configure
+      if block_given?
+        yield(Configuration.default)
+      else
+        Configuration.default
+      end
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/api/usage_api.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/api/usage_api.rb
new file mode 100644
index 00000000000..a7f33e7a2ed
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/api/usage_api.rb
@@ -0,0 +1,142 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+require 'cgi'
+
+module Petstore
+  class UsageApi
+    attr_accessor :api_client
+
+    def initialize(api_client = ApiClient.default)
+      @api_client = api_client
+    end
+    # Use alias to array
+    # Use alias to array
+    # @param [Hash] opts the optional parameters
+    # @option opts [ArrayAlias] :array_alias 
+    # @return [Object]
+    def array(opts = {})
+      data, _status_code, _headers = array_with_http_info(opts)
+      data
+    end
+
+    # Use alias to array
+    # Use alias to array
+    # @param [Hash] opts the optional parameters
+    # @option opts [ArrayAlias] :array_alias 
+    # @return [Array<(Object, Integer, Hash)>] Object data, response status code and response headers
+    def array_with_http_info(opts = {})
+      if @api_client.config.debugging
+        @api_client.config.logger.debug 'Calling API: UsageApi.array ...'
+      end
+      # resource path
+      local_var_path = '/array'
+
+      # query parameters
+      query_params = opts[:query_params] || {}
+
+      # header parameters
+      header_params = opts[:header_params] || {}
+      # HTTP header 'Accept' (if needed)
+      header_params['Accept'] = @api_client.select_header_accept(['application/json'])
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
+
+      # form parameters
+      form_params = opts[:form_params] || {}
+
+      # http body (model)
+      post_body = opts[:debug_body] || @api_client.object_to_http_body(opts[:'array_alias'])
+
+      # return_type
+      return_type = opts[:debug_return_type] || 'Object'
+
+      # auth_names
+      auth_names = opts[:debug_auth_names] || []
+
+      new_options = opts.merge(
+        :header_params => header_params,
+        :query_params => query_params,
+        :form_params => form_params,
+        :body => post_body,
+        :auth_names => auth_names,
+        :return_type => return_type
+      )
+
+      data, status_code, headers = @api_client.call_api(:GET, local_var_path, new_options)
+      if @api_client.config.debugging
+        @api_client.config.logger.debug "API called: UsageApi#array\nData: #{data.inspect}\nStatus code: #{status_code}\nHeaders: #{headers}"
+      end
+      return data, status_code, headers
+    end
+
+    # Use alias to map
+    # Use alias to map
+    # @param [Hash] opts the optional parameters
+    # @option opts [MapAlias] :map_alias 
+    # @return [Object]
+    def map(opts = {})
+      data, _status_code, _headers = map_with_http_info(opts)
+      data
+    end
+
+    # Use alias to map
+    # Use alias to map
+    # @param [Hash] opts the optional parameters
+    # @option opts [MapAlias] :map_alias 
+    # @return [Array<(Object, Integer, Hash)>] Object data, response status code and response headers
+    def map_with_http_info(opts = {})
+      if @api_client.config.debugging
+        @api_client.config.logger.debug 'Calling API: UsageApi.map ...'
+      end
+      # resource path
+      local_var_path = '/map'
+
+      # query parameters
+      query_params = opts[:query_params] || {}
+
+      # header parameters
+      header_params = opts[:header_params] || {}
+      # HTTP header 'Accept' (if needed)
+      header_params['Accept'] = @api_client.select_header_accept(['application/json'])
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
+
+      # form parameters
+      form_params = opts[:form_params] || {}
+
+      # http body (model)
+      post_body = opts[:debug_body] || @api_client.object_to_http_body(opts[:'map_alias'])
+
+      # return_type
+      return_type = opts[:debug_return_type] || 'Object'
+
+      # auth_names
+      auth_names = opts[:debug_auth_names] || []
+
+      new_options = opts.merge(
+        :header_params => header_params,
+        :query_params => query_params,
+        :form_params => form_params,
+        :body => post_body,
+        :auth_names => auth_names,
+        :return_type => return_type
+      )
+
+      data, status_code, headers = @api_client.call_api(:GET, local_var_path, new_options)
+      if @api_client.config.debugging
+        @api_client.config.logger.debug "API called: UsageApi#map\nData: #{data.inspect}\nStatus code: #{status_code}\nHeaders: #{headers}"
+      end
+      return data, status_code, headers
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/api_client.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/api_client.rb
new file mode 100644
index 00000000000..228c890a379
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/api_client.rb
@@ -0,0 +1,387 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+require 'date'
+require 'json'
+require 'logger'
+require 'tempfile'
+require 'typhoeus'
+
+module Petstore
+  class ApiClient
+    # The Configuration object holding settings to be used in the API client.
+    attr_accessor :config
+
+    # Defines the headers to be used in HTTP requests of all API calls by default.
+    #
+    # @return [Hash]
+    attr_accessor :default_headers
+
+    # Initializes the ApiClient
+    # @option config [Configuration] Configuration for initializing the object, default to Configuration.default
+    def initialize(config = Configuration.default)
+      @config = config
+      @user_agent = "OpenAPI-Generator/#{VERSION}/ruby"
+      @default_headers = {
+        'Content-Type' => 'application/json',
+        'User-Agent' => @user_agent
+      }
+    end
+
+    def self.default
+      @@default ||= ApiClient.new
+    end
+
+    # Call an API with given options.
+    #
+    # @return [Array<(Object, Integer, Hash)>] an array of 3 elements:
+    #   the data deserialized from response body (could be nil), response status code and response headers.
+    def call_api(http_method, path, opts = {})
+      request = build_request(http_method, path, opts)
+      response = request.run
+
+      if @config.debugging
+        @config.logger.debug "HTTP response body ~BEGIN~\n#{response.body}\n~END~\n"
+      end
+
+      unless response.success?
+        if response.timed_out?
+          fail ApiError.new('Connection timed out')
+        elsif response.code == 0
+          # Errors from libcurl will be made visible here
+          fail ApiError.new(:code => 0,
+                            :message => response.return_message)
+        else
+          fail ApiError.new(:code => response.code,
+                            :response_headers => response.headers,
+                            :response_body => response.body),
+               response.status_message
+        end
+      end
+
+      if opts[:return_type]
+        data = deserialize(response, opts[:return_type])
+      else
+        data = nil
+      end
+      return data, response.code, response.headers
+    end
+
+    # Builds the HTTP request
+    #
+    # @param [String] http_method HTTP method/verb (e.g. POST)
+    # @param [String] path URL path (e.g. /account/new)
+    # @option opts [Hash] :header_params Header parameters
+    # @option opts [Hash] :query_params Query parameters
+    # @option opts [Hash] :form_params Query parameters
+    # @option opts [Object] :body HTTP body (JSON/XML)
+    # @return [Typhoeus::Request] A Typhoeus Request
+    def build_request(http_method, path, opts = {})
+      url = build_request_url(path)
+      http_method = http_method.to_sym.downcase
+
+      header_params = @default_headers.merge(opts[:header_params] || {})
+      query_params = opts[:query_params] || {}
+      form_params = opts[:form_params] || {}
+
+
+      # set ssl_verifyhosts option based on @config.verify_ssl_host (true/false)
+      _verify_ssl_host = @config.verify_ssl_host ? 2 : 0
+
+      req_opts = {
+        :method => http_method,
+        :headers => header_params,
+        :params => query_params,
+        :params_encoding => @config.params_encoding,
+        :timeout => @config.timeout,
+        :ssl_verifypeer => @config.verify_ssl,
+        :ssl_verifyhost => _verify_ssl_host,
+        :sslcert => @config.cert_file,
+        :sslkey => @config.key_file,
+        :verbose => @config.debugging
+      }
+
+      # set custom cert, if provided
+      req_opts[:cainfo] = @config.ssl_ca_cert if @config.ssl_ca_cert
+
+      if [:post, :patch, :put, :delete].include?(http_method)
+        req_body = build_request_body(header_params, form_params, opts[:body])
+        req_opts.update :body => req_body
+        if @config.debugging
+          @config.logger.debug "HTTP request body param ~BEGIN~\n#{req_body}\n~END~\n"
+        end
+      end
+
+      request = Typhoeus::Request.new(url, req_opts)
+      download_file(request) if opts[:return_type] == 'File'
+      request
+    end
+
+    # Builds the HTTP request body
+    #
+    # @param [Hash] header_params Header parameters
+    # @param [Hash] form_params Query parameters
+    # @param [Object] body HTTP body (JSON/XML)
+    # @return [String] HTTP body data in the form of string
+    def build_request_body(header_params, form_params, body)
+      # http form
+      if header_params['Content-Type'] == 'application/x-www-form-urlencoded' ||
+          header_params['Content-Type'] == 'multipart/form-data'
+        data = {}
+        form_params.each do |key, value|
+          case value
+          when ::File, ::Array, nil
+            # let typhoeus handle File, Array and nil parameters
+            data[key] = value
+          else
+            data[key] = value.to_s
+          end
+        end
+      elsif body
+        data = body.is_a?(String) ? body : body.to_json
+      else
+        data = nil
+      end
+      data
+    end
+
+    # Check if the given MIME is a JSON MIME.
+    # JSON MIME examples:
+    #   application/json
+    #   application/json; charset=UTF8
+    #   APPLICATION/JSON
+    #   */*
+    # @param [String] mime MIME
+    # @return [Boolean] True if the MIME is application/json
+    def json_mime?(mime)
+      (mime == '*/*') || !(mime =~ /Application\/.*json(?!p)(;.*)?/i).nil?
+    end
+
+    # Deserialize the response to the given return type.
+    #
+    # @param [Response] response HTTP response
+    # @param [String] return_type some examples: "User", "Array<User>", "Hash<String, Integer>"
+    def deserialize(response, return_type)
+      body = response.body
+
+      # handle file downloading - return the File instance processed in request callbacks
+      # note that response body is empty when the file is written in chunks in request on_body callback
+      return @tempfile if return_type == 'File'
+
+      return nil if body.nil? || body.empty?
+
+      # return response body directly for String return type
+      return body if return_type == 'String'
+
+      # ensuring a default content type
+      content_type = response.headers['Content-Type'] || 'application/json'
+
+      fail "Content-Type is not supported: #{content_type}" unless json_mime?(content_type)
+
+      begin
+        data = JSON.parse("[#{body}]", :symbolize_names => true)[0]
+      rescue JSON::ParserError => e
+        if %w(String Date DateTime).include?(return_type)
+          data = body
+        else
+          raise e
+        end
+      end
+
+      convert_to_type data, return_type
+    end
+
+    # Convert data to the given return type.
+    # @param [Object] data Data to be converted
+    # @param [String] return_type Return type
+    # @return [Mixed] Data in a particular type
+    def convert_to_type(data, return_type)
+      return nil if data.nil?
+      case return_type
+      when 'String'
+        data.to_s
+      when 'Integer'
+        data.to_i
+      when 'Float'
+        data.to_f
+      when 'Boolean'
+        data == true
+      when 'DateTime'
+        # parse date time (expecting ISO 8601 format)
+        DateTime.parse data
+      when 'Date'
+        # parse date time (expecting ISO 8601 format)
+        Date.parse data
+      when 'Object'
+        # generic object (usually a Hash), return directly
+        data
+      when /\AArray<(.+)>\z/
+        # e.g. Array<Pet>
+        sub_type = $1
+        data.map { |item| convert_to_type(item, sub_type) }
+      when /\AHash\<String, (.+)\>\z/
+        # e.g. Hash<String, Integer>
+        sub_type = $1
+        {}.tap do |hash|
+          data.each { |k, v| hash[k] = convert_to_type(v, sub_type) }
+        end
+      else
+        # models, e.g. Pet
+        Petstore.const_get(return_type).build_from_hash(data)
+      end
+    end
+
+    # Save response body into a file in (the defined) temporary folder, using the filename
+    # from the "Content-Disposition" header if provided, otherwise a random filename.
+    # The response body is written to the file in chunks in order to handle files which
+    # size is larger than maximum Ruby String or even larger than the maximum memory a Ruby
+    # process can use.
+    #
+    # @see Configuration#temp_folder_path
+    def download_file(request)
+      tempfile = nil
+      encoding = nil
+      request.on_headers do |response|
+        content_disposition = response.headers['Content-Disposition']
+        if content_disposition && content_disposition =~ /filename=/i
+          filename = content_disposition[/filename=['"]?([^'"\s]+)['"]?/, 1]
+          prefix = sanitize_filename(filename)
+        else
+          prefix = 'download-'
+        end
+        prefix = prefix + '-' unless prefix.end_with?('-')
+        encoding = response.body.encoding
+        tempfile = Tempfile.open(prefix, @config.temp_folder_path, encoding: encoding)
+        @tempfile = tempfile
+      end
+      request.on_body do |chunk|
+        chunk.force_encoding(encoding)
+        tempfile.write(chunk)
+      end
+      request.on_complete do |response|
+        if tempfile
+          tempfile.close
+          @config.logger.info "Temp file written to #{tempfile.path}, please copy the file to a proper folder "\
+                              "with e.g. `FileUtils.cp(tempfile.path, '/new/file/path')` otherwise the temp file "\
+                              "will be deleted automatically with GC. It's also recommended to delete the temp file "\
+                              "explicitly with `tempfile.delete`"
+        end
+      end
+    end
+
+    # Sanitize filename by removing path.
+    # e.g. ../../sun.gif becomes sun.gif
+    #
+    # @param [String] filename the filename to be sanitized
+    # @return [String] the sanitized filename
+    def sanitize_filename(filename)
+      filename.gsub(/.*[\/\\]/, '')
+    end
+
+    def build_request_url(path)
+      # Add leading and trailing slashes to path
+      path = "/#{path}".gsub(/\/+/, '/')
+      @config.base_url + path
+    end
+
+    # Update hearder and query params based on authentication settings.
+    #
+    # @param [Hash] header_params Header parameters
+    # @param [Hash] query_params Query parameters
+    # @param [String] auth_names Authentication scheme name
+    def update_params_for_auth!(header_params, query_params, auth_names)
+      Array(auth_names).each do |auth_name|
+        auth_setting = @config.auth_settings[auth_name]
+        next unless auth_setting
+        case auth_setting[:in]
+        when 'header' then header_params[auth_setting[:key]] = auth_setting[:value]
+        when 'query'  then query_params[auth_setting[:key]] = auth_setting[:value]
+        else fail ArgumentError, 'Authentication token must be in `query` of `header`'
+        end
+      end
+    end
+
+    # Sets user agent in HTTP header
+    #
+    # @param [String] user_agent User agent (e.g. openapi-generator/ruby/1.0.0)
+    def user_agent=(user_agent)
+      @user_agent = user_agent
+      @default_headers['User-Agent'] = @user_agent
+    end
+
+    # Return Accept header based on an array of accepts provided.
+    # @param [Array] accepts array for Accept
+    # @return [String] the Accept header (e.g. application/json)
+    def select_header_accept(accepts)
+      return nil if accepts.nil? || accepts.empty?
+      # use JSON when present, otherwise use all of the provided
+      json_accept = accepts.find { |s| json_mime?(s) }
+      json_accept || accepts.join(',')
+    end
+
+    # Return Content-Type header based on an array of content types provided.
+    # @param [Array] content_types array for Content-Type
+    # @return [String] the Content-Type header  (e.g. application/json)
+    def select_header_content_type(content_types)
+      # use application/json by default
+      return 'application/json' if content_types.nil? || content_types.empty?
+      # use JSON when present, otherwise use the first one
+      json_content_type = content_types.find { |s| json_mime?(s) }
+      json_content_type || content_types.first
+    end
+
+    # Convert object (array, hash, object, etc) to JSON string.
+    # @param [Object] model object to be converted into JSON string
+    # @return [String] JSON string representation of the object
+    def object_to_http_body(model)
+      return model if model.nil? || model.is_a?(String)
+      local_body = nil
+      if model.is_a?(Array)
+        local_body = model.map { |m| object_to_hash(m) }
+      else
+        local_body = object_to_hash(model)
+      end
+      local_body.to_json
+    end
+
+    # Convert object(non-array) to hash.
+    # @param [Object] obj object to be converted into JSON string
+    # @return [String] JSON string representation of the object
+    def object_to_hash(obj)
+      if obj.respond_to?(:to_hash)
+        obj.to_hash
+      else
+        obj
+      end
+    end
+
+    # Build parameter value according to the given collection format.
+    # @param [String] collection_format one of :csv, :ssv, :tsv, :pipes and :multi
+    def build_collection_param(param, collection_format)
+      case collection_format
+      when :csv
+        param.join(',')
+      when :ssv
+        param.join(' ')
+      when :tsv
+        param.join("\t")
+      when :pipes
+        param.join('|')
+      when :multi
+        # return the array directly as typhoeus will handle it as expected
+        param
+      else
+        fail "unknown collection format: #{collection_format.inspect}"
+      end
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/api_error.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/api_error.rb
new file mode 100644
index 00000000000..380f7058c29
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/api_error.rb
@@ -0,0 +1,57 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+module Petstore
+  class ApiError < StandardError
+    attr_reader :code, :response_headers, :response_body
+
+    # Usage examples:
+    #   ApiError.new
+    #   ApiError.new("message")
+    #   ApiError.new(:code => 500, :response_headers => {}, :response_body => "")
+    #   ApiError.new(:code => 404, :message => "Not Found")
+    def initialize(arg = nil)
+      if arg.is_a? Hash
+        if arg.key?(:message) || arg.key?('message')
+          super(arg[:message] || arg['message'])
+        else
+          super arg
+        end
+
+        arg.each do |k, v|
+          instance_variable_set "@#{k}", v
+        end
+      else
+        super arg
+      end
+    end
+
+    # Override to_s to display a friendly error message
+    def to_s
+      message
+    end
+
+    def message
+      if @message.nil?
+        msg = "Error message: the server returns an error"
+      else
+        msg = @message
+      end
+
+      msg += "\nHTTP status code: #{code}" if code
+      msg += "\nResponse headers: #{response_headers}" if response_headers
+      msg += "\nResponse body: #{response_body}" if response_body
+
+      msg
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/configuration.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/configuration.rb
new file mode 100644
index 00000000000..85f1d940a40
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/configuration.rb
@@ -0,0 +1,241 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+module Petstore
+  class Configuration
+    # Defines url scheme
+    attr_accessor :scheme
+
+    # Defines url host
+    attr_accessor :host
+
+    # Defines url base path
+    attr_accessor :base_path
+
+    # Defines API keys used with API Key authentications.
+    #
+    # @return [Hash] key: parameter name, value: parameter value (API key)
+    #
+    # @example parameter name is "api_key", API key is "xxx" (e.g. "api_key=xxx" in query string)
+    #   config.api_key['api_key'] = 'xxx'
+    attr_accessor :api_key
+
+    # Defines API key prefixes used with API Key authentications.
+    #
+    # @return [Hash] key: parameter name, value: API key prefix
+    #
+    # @example parameter name is "Authorization", API key prefix is "Token" (e.g. "Authorization: Token xxx" in headers)
+    #   config.api_key_prefix['api_key'] = 'Token'
+    attr_accessor :api_key_prefix
+
+    # Defines the username used with HTTP basic authentication.
+    #
+    # @return [String]
+    attr_accessor :username
+
+    # Defines the password used with HTTP basic authentication.
+    #
+    # @return [String]
+    attr_accessor :password
+
+    # Defines the access token (Bearer) used with OAuth2.
+    attr_accessor :access_token
+
+    # Set this to enable/disable debugging. When enabled (set to true), HTTP request/response
+    # details will be logged with `logger.debug` (see the `logger` attribute).
+    # Default to false.
+    #
+    # @return [true, false]
+    attr_accessor :debugging
+
+    # Defines the logger used for debugging.
+    # Default to `Rails.logger` (when in Rails) or logging to STDOUT.
+    #
+    # @return [#debug]
+    attr_accessor :logger
+
+    # Defines the temporary folder to store downloaded files
+    # (for API endpoints that have file response).
+    # Default to use `Tempfile`.
+    #
+    # @return [String]
+    attr_accessor :temp_folder_path
+
+    # The time limit for HTTP request in seconds.
+    # Default to 0 (never times out).
+    attr_accessor :timeout
+
+    # Set this to false to skip client side validation in the operation.
+    # Default to true.
+    # @return [true, false]
+    attr_accessor :client_side_validation
+
+    ### TLS/SSL setting
+    # Set this to false to skip verifying SSL certificate when calling API from https server.
+    # Default to true.
+    #
+    # @note Do NOT set it to false in production code, otherwise you would face multiple types of cryptographic attacks.
+    #
+    # @return [true, false]
+    attr_accessor :verify_ssl
+
+    ### TLS/SSL setting
+    # Set this to false to skip verifying SSL host name
+    # Default to true.
+    #
+    # @note Do NOT set it to false in production code, otherwise you would face multiple types of cryptographic attacks.
+    #
+    # @return [true, false]
+    attr_accessor :verify_ssl_host
+
+    ### TLS/SSL setting
+    # Set this to customize the certificate file to verify the peer.
+    #
+    # @return [String] the path to the certificate file
+    #
+    # @see The `cainfo` option of Typhoeus, `--cert` option of libcurl. Related source code:
+    # https://github.com/typhoeus/typhoeus/blob/master/lib/typhoeus/easy_factory.rb#L145
+    attr_accessor :ssl_ca_cert
+
+    ### TLS/SSL setting
+    # Client certificate file (for client certificate)
+    attr_accessor :cert_file
+
+    ### TLS/SSL setting
+    # Client private key file (for client certificate)
+    attr_accessor :key_file
+
+    # Set this to customize parameters encoding of array parameter with multi collectionFormat.
+    # Default to nil.
+    #
+    # @see The params_encoding option of Ethon. Related source code:
+    # https://github.com/typhoeus/ethon/blob/master/lib/ethon/easy/queryable.rb#L96
+    attr_accessor :params_encoding
+
+    attr_accessor :inject_format
+
+    attr_accessor :force_ending_format
+
+    def initialize
+      @scheme = 'http'
+      @host = 'petstore.swagger.io:-1'
+      @base_path = '/v2'
+      @api_key = {}
+      @api_key_prefix = {}
+      @timeout = 0
+      @client_side_validation = true
+      @verify_ssl = true
+      @verify_ssl_host = true
+      @params_encoding = nil
+      @cert_file = nil
+      @key_file = nil
+      @debugging = false
+      @inject_format = false
+      @force_ending_format = false
+      @logger = defined?(Rails) ? Rails.logger : Logger.new(STDOUT)
+
+      yield(self) if block_given?
+    end
+
+    # The default Configuration object.
+    def self.default
+      @@default ||= Configuration.new
+    end
+
+    def configure
+      yield(self) if block_given?
+    end
+
+    def scheme=(scheme)
+      # remove :// from scheme
+      @scheme = scheme.sub(/:\/\//, '')
+    end
+
+    def host=(host)
+      # remove http(s):// and anything after a slash
+      @host = host.sub(/https?:\/\//, '').split('/').first
+    end
+
+    def base_path=(base_path)
+      # Add leading and trailing slashes to base_path
+      @base_path = "/#{base_path}".gsub(/\/+/, '/')
+      @base_path = '' if @base_path == '/'
+    end
+
+    def base_url
+      "#{scheme}://#{[host, base_path].join('/').gsub(/\/+/, '/')}".sub(/\/+\z/, '')
+    end
+
+    # Gets API key (with prefix if set).
+    # @param [String] param_name the parameter name of API key auth
+    def api_key_with_prefix(param_name)
+      if @api_key_prefix[param_name]
+        "#{@api_key_prefix[param_name]} #{@api_key[param_name]}"
+      else
+        @api_key[param_name]
+      end
+    end
+
+    # Gets Basic Auth token string
+    def basic_auth_token
+      'Basic ' + ["#{username}:#{password}"].pack('m').delete("\r\n")
+    end
+
+    # Returns Auth Settings hash for api client.
+    def auth_settings
+      {
+      }
+    end
+
+    # Returns an array of Server setting
+    def server_settings
+      [
+        {
+          url: "http://petstore.swagger.io/v2",
+          description: "petstore server",
+        }
+      ]
+    end
+
+    # Returns URL based on server settings
+    #
+    # @param index array index of the server settings
+    # @param variables hash of variable and the corresponding value
+    def server_url(index, variables = {})
+      servers = server_settings
+
+      # check array index out of bound
+      if (index < 0 || index >= servers.size)
+        fail ArgumentError, "Invalid index #{index} when selecting the server. Must be less than #{servers.size}"
+      end
+
+      server = servers[index]
+      url = server[:url]
+
+      # go through variable and assign a value
+      server[:variables].each do |name, variable|
+        if variables.key?(name)
+          if (server[:variables][name][:enum_values].include? variables[name])
+            url.gsub! "{" + name.to_s + "}", variables[name]
+          else
+            fail ArgumentError, "The variable `#{name}` in the server URL has invalid value #{variables[name]}. Must be #{server[:variables][name][:enum_values]}."
+          end
+        else
+          # use default value
+          url.gsub! "{" + name.to_s + "}", server[:variables][name][:default_value]
+        end
+      end
+
+      url
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/array_alias.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/array_alias.rb
new file mode 100644
index 00000000000..77ca2e8d358
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/array_alias.rb
@@ -0,0 +1,203 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+require 'date'
+
+module Petstore
+  class ArrayAlias < Array
+    # Attribute mapping from ruby-style variable name to JSON key.
+    def self.attribute_map
+      {
+      }
+    end
+
+    # Attribute type mapping.
+    def self.openapi_types
+      {
+      }
+    end
+
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
+    # Initializes the object
+    # @param [Hash] attributes Model attributes in the form of hash
+    def initialize(attributes = {})
+      if (!attributes.is_a?(Hash))
+        fail ArgumentError, "The input argument (attributes) must be a hash in `Petstore::ArrayAlias` initialize method"
+      end
+
+      # check to see if the attribute exists and convert string to symbol for hash key
+      attributes = attributes.each_with_object({}) { |(k, v), h|
+        if (!self.class.attribute_map.key?(k.to_sym))
+          fail ArgumentError, "`#{k}` is not a valid attribute in `Petstore::ArrayAlias`. Please check the name to make sure it's valid. List of attributes: " + self.class.attribute_map.keys.inspect
+        end
+        h[k.to_sym] = v
+      }
+
+      # call parent's initialize
+      super(attributes)
+    end
+
+    # Show invalid properties with the reasons. Usually used together with valid?
+    # @return Array for valid properties with the reasons
+    def list_invalid_properties
+      invalid_properties = super
+      invalid_properties
+    end
+
+    # Check to see if the all the properties in the model are valid
+    # @return true if the model is valid
+    def valid?
+      true && super
+    end
+
+    # Checks equality by comparing each attribute.
+    # @param [Object] Object to be compared
+    def ==(o)
+      return true if self.equal?(o)
+      self.class == o.class && super(o)
+    end
+
+    # @see the `==` method
+    # @param [Object] Object to be compared
+    def eql?(o)
+      self == o
+    end
+
+    # Calculates hash code according to all attributes.
+    # @return [Integer] Hash code
+    def hash
+      [].hash
+    end
+
+    # Builds the object from hash
+    # @param [Hash] attributes Model attributes in the form of hash
+    # @return [Object] Returns the model itself
+    def self.build_from_hash(attributes)
+      new.build_from_hash(attributes)
+    end
+
+    # Builds the object from hash
+    # @param [Hash] attributes Model attributes in the form of hash
+    # @return [Object] Returns the model itself
+    def build_from_hash(attributes)
+      return nil unless attributes.is_a?(Hash)
+      super(attributes)
+      self.class.openapi_types.each_pair do |key, type|
+        if type =~ /\AArray<(.*)>/i
+          # check to ensure the input is an array given that the attribute
+          # is documented as an array but the input is not
+          if attributes[self.class.attribute_map[key]].is_a?(Array)
+            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          end
+        elsif !attributes[self.class.attribute_map[key]].nil?
+          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        end
+      end
+
+      self
+    end
+
+    # Deserializes the data based on type
+    # @param string type Data type
+    # @param string value Value to be deserialized
+    # @return [Object] Deserialized data
+    def _deserialize(type, value)
+      case type.to_sym
+      when :DateTime
+        DateTime.parse(value)
+      when :Date
+        Date.parse(value)
+      when :String
+        value.to_s
+      when :Integer
+        value.to_i
+      when :Float
+        value.to_f
+      when :Boolean
+        if value.to_s =~ /\A(true|t|yes|y|1)\z/i
+          true
+        else
+          false
+        end
+      when :Object
+        # generic object (usually a Hash), return directly
+        value
+      when /\AArray<(?<inner_type>.+)>\z/
+        inner_type = Regexp.last_match[:inner_type]
+        value.map { |v| _deserialize(inner_type, v) }
+      when /\AHash<(?<k_type>.+?), (?<v_type>.+)>\z/
+        k_type = Regexp.last_match[:k_type]
+        v_type = Regexp.last_match[:v_type]
+        {}.tap do |hash|
+          value.each do |k, v|
+            hash[_deserialize(k_type, k)] = _deserialize(v_type, v)
+          end
+        end
+      else # model
+        Petstore.const_get(type).build_from_hash(value)
+      end
+    end
+
+    # Returns the string representation of the object
+    # @return [String] String presentation of the object
+    def to_s
+      to_hash.to_s
+    end
+
+    # to_body is an alias to to_hash (backward compatibility)
+    # @return [Hash] Returns the object in the form of hash
+    def to_body
+      to_hash
+    end
+
+    # Returns the object in the form of hash
+    # @return [Hash] Returns the object in the form of hash
+    def to_hash
+      hash = super
+      self.class.attribute_map.each_pair do |attr, param|
+        value = self.send(attr)
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
+        hash[param] = _to_hash(value)
+      end
+      hash
+    end
+
+    # Outputs non-array value in the form of hash
+    # For object, use to_hash. Otherwise, just return the value
+    # @param [Object] value Any valid value
+    # @return [Hash] Returns the value in the form of hash
+    def _to_hash(value)
+      if value.is_a?(Array)
+        value.compact.map { |v| _to_hash(v) }
+      elsif value.is_a?(Hash)
+        {}.tap do |hash|
+          value.each { |k, v| hash[k] = _to_hash(v) }
+        end
+      elsif value.respond_to? :to_hash
+        value.to_hash
+      else
+        value
+      end
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/map_alias.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/map_alias.rb
new file mode 100644
index 00000000000..22ae17aeb88
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/models/map_alias.rb
@@ -0,0 +1,199 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+require 'date'
+
+module Petstore
+  class MapAlias
+    # Attribute mapping from ruby-style variable name to JSON key.
+    def self.attribute_map
+      {
+      }
+    end
+
+    # Attribute type mapping.
+    def self.openapi_types
+      {
+      }
+    end
+
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
+    # Initializes the object
+    # @param [Hash] attributes Model attributes in the form of hash
+    def initialize(attributes = {})
+      if (!attributes.is_a?(Hash))
+        fail ArgumentError, "The input argument (attributes) must be a hash in `Petstore::MapAlias` initialize method"
+      end
+
+      # check to see if the attribute exists and convert string to symbol for hash key
+      attributes = attributes.each_with_object({}) { |(k, v), h|
+        if (!self.class.attribute_map.key?(k.to_sym))
+          fail ArgumentError, "`#{k}` is not a valid attribute in `Petstore::MapAlias`. Please check the name to make sure it's valid. List of attributes: " + self.class.attribute_map.keys.inspect
+        end
+        h[k.to_sym] = v
+      }
+    end
+
+    # Show invalid properties with the reasons. Usually used together with valid?
+    # @return Array for valid properties with the reasons
+    def list_invalid_properties
+      invalid_properties = Array.new
+      invalid_properties
+    end
+
+    # Check to see if the all the properties in the model are valid
+    # @return true if the model is valid
+    def valid?
+      true
+    end
+
+    # Checks equality by comparing each attribute.
+    # @param [Object] Object to be compared
+    def ==(o)
+      return true if self.equal?(o)
+      self.class == o.class
+    end
+
+    # @see the `==` method
+    # @param [Object] Object to be compared
+    def eql?(o)
+      self == o
+    end
+
+    # Calculates hash code according to all attributes.
+    # @return [Integer] Hash code
+    def hash
+      [].hash
+    end
+
+    # Builds the object from hash
+    # @param [Hash] attributes Model attributes in the form of hash
+    # @return [Object] Returns the model itself
+    def self.build_from_hash(attributes)
+      new.build_from_hash(attributes)
+    end
+
+    # Builds the object from hash
+    # @param [Hash] attributes Model attributes in the form of hash
+    # @return [Object] Returns the model itself
+    def build_from_hash(attributes)
+      return nil unless attributes.is_a?(Hash)
+      self.class.openapi_types.each_pair do |key, type|
+        if type =~ /\AArray<(.*)>/i
+          # check to ensure the input is an array given that the attribute
+          # is documented as an array but the input is not
+          if attributes[self.class.attribute_map[key]].is_a?(Array)
+            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          end
+        elsif !attributes[self.class.attribute_map[key]].nil?
+          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        end
+      end
+
+      self
+    end
+
+    # Deserializes the data based on type
+    # @param string type Data type
+    # @param string value Value to be deserialized
+    # @return [Object] Deserialized data
+    def _deserialize(type, value)
+      case type.to_sym
+      when :DateTime
+        DateTime.parse(value)
+      when :Date
+        Date.parse(value)
+      when :String
+        value.to_s
+      when :Integer
+        value.to_i
+      when :Float
+        value.to_f
+      when :Boolean
+        if value.to_s =~ /\A(true|t|yes|y|1)\z/i
+          true
+        else
+          false
+        end
+      when :Object
+        # generic object (usually a Hash), return directly
+        value
+      when /\AArray<(?<inner_type>.+)>\z/
+        inner_type = Regexp.last_match[:inner_type]
+        value.map { |v| _deserialize(inner_type, v) }
+      when /\AHash<(?<k_type>.+?), (?<v_type>.+)>\z/
+        k_type = Regexp.last_match[:k_type]
+        v_type = Regexp.last_match[:v_type]
+        {}.tap do |hash|
+          value.each do |k, v|
+            hash[_deserialize(k_type, k)] = _deserialize(v_type, v)
+          end
+        end
+      else # model
+        Petstore.const_get(type).build_from_hash(value)
+      end
+    end
+
+    # Returns the string representation of the object
+    # @return [String] String presentation of the object
+    def to_s
+      to_hash.to_s
+    end
+
+    # to_body is an alias to to_hash (backward compatibility)
+    # @return [Hash] Returns the object in the form of hash
+    def to_body
+      to_hash
+    end
+
+    # Returns the object in the form of hash
+    # @return [Hash] Returns the object in the form of hash
+    def to_hash
+      hash = {}
+      self.class.attribute_map.each_pair do |attr, param|
+        value = self.send(attr)
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
+        hash[param] = _to_hash(value)
+      end
+      hash
+    end
+
+    # Outputs non-array value in the form of hash
+    # For object, use to_hash. Otherwise, just return the value
+    # @param [Object] value Any valid value
+    # @return [Hash] Returns the value in the form of hash
+    def _to_hash(value)
+      if value.is_a?(Array)
+        value.compact.map { |v| _to_hash(v) }
+      elsif value.is_a?(Hash)
+        {}.tap do |hash|
+          value.each { |k, v| hash[k] = _to_hash(v) }
+        end
+      elsif value.respond_to? :to_hash
+        value.to_hash
+      else
+        value
+      end
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/version.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/version.rb
new file mode 100644
index 00000000000..e1008320191
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/version.rb
@@ -0,0 +1,15 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+module Petstore
+  VERSION = '1.0.0'
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/petstore.gemspec b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/petstore.gemspec
new file mode 100644
index 00000000000..b1bd56ee574
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/petstore.gemspec
@@ -0,0 +1,38 @@
+# -*- encoding: utf-8 -*-
+
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+$:.push File.expand_path("../lib", __FILE__)
+require "petstore/version"
+
+Gem::Specification.new do |s|
+  s.name        = "petstore"
+  s.version     = Petstore::VERSION
+  s.platform    = Gem::Platform::RUBY
+  s.authors     = ["OpenAPI-Generator"]
+  s.email       = [""]
+  s.homepage    = "https://openapi-generator.tech"
+  s.summary     = "OpenAPI Extension generating aliases to maps and arrays as models Ruby Gem"
+  s.description = "This specification shows how to generate aliases to maps and arrays as models."
+  s.license     = "Unlicense"
+  s.required_ruby_version = ">= 1.9"
+
+  s.add_runtime_dependency 'typhoeus', '~> 1.0', '>= 1.0.1'
+
+  s.add_development_dependency 'rspec', '~> 3.6', '>= 3.6.0'
+
+  s.files         = `find *`.split("\n").uniq.sort.select { |f| !f.empty? }
+  s.test_files    = `find spec/*`.split("\n")
+  s.executables   = []
+  s.require_paths = ["lib"]
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/api/usage_api_spec.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/api/usage_api_spec.rb
new file mode 100644
index 00000000000..66607732925
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/api/usage_api_spec.rb
@@ -0,0 +1,59 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+require 'spec_helper'
+require 'json'
+
+# Unit tests for Petstore::UsageApi
+# Automatically generated by openapi-generator (https://openapi-generator.tech)
+# Please update as you see appropriate
+describe 'UsageApi' do
+  before do
+    # run before each test
+    @api_instance = Petstore::UsageApi.new
+  end
+
+  after do
+    # run after each test
+  end
+
+  describe 'test an instance of UsageApi' do
+    it 'should create an instance of UsageApi' do
+      expect(@api_instance).to be_instance_of(Petstore::UsageApi)
+    end
+  end
+
+  # unit tests for array
+  # Use alias to array
+  # Use alias to array
+  # @param [Hash] opts the optional parameters
+  # @option opts [ArrayAlias] :array_alias 
+  # @return [Object]
+  describe 'array test' do
+    it 'should work' do
+      # assertion here. ref: https://www.relishapp.com/rspec/rspec-expectations/docs/built-in-matchers
+    end
+  end
+
+  # unit tests for map
+  # Use alias to map
+  # Use alias to map
+  # @param [Hash] opts the optional parameters
+  # @option opts [MapAlias] :map_alias 
+  # @return [Object]
+  describe 'map test' do
+    it 'should work' do
+      # assertion here. ref: https://www.relishapp.com/rspec/rspec-expectations/docs/built-in-matchers
+    end
+  end
+
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/api_client_spec.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/api_client_spec.rb
new file mode 100644
index 00000000000..565a3e74df0
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/api_client_spec.rb
@@ -0,0 +1,226 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+require 'spec_helper'
+
+describe Petstore::ApiClient do
+  context 'initialization' do
+    context 'URL stuff' do
+      context 'host' do
+        it 'removes http from host' do
+          Petstore.configure { |c| c.host = 'http://example.com' }
+          expect(Petstore::Configuration.default.host).to eq('example.com')
+        end
+
+        it 'removes https from host' do
+          Petstore.configure { |c| c.host = 'https://wookiee.com' }
+          expect(Petstore::ApiClient.default.config.host).to eq('wookiee.com')
+        end
+
+        it 'removes trailing path from host' do
+          Petstore.configure { |c| c.host = 'hobo.com/v4' }
+          expect(Petstore::Configuration.default.host).to eq('hobo.com')
+        end
+      end
+
+      context 'base_path' do
+        it "prepends a slash to base_path" do
+          Petstore.configure { |c| c.base_path = 'v4/dog' }
+          expect(Petstore::Configuration.default.base_path).to eq('/v4/dog')
+        end
+
+        it "doesn't prepend a slash if one is already there" do
+          Petstore.configure { |c| c.base_path = '/v4/dog' }
+          expect(Petstore::Configuration.default.base_path).to eq('/v4/dog')
+        end
+
+        it "ends up as a blank string if nil" do
+          Petstore.configure { |c| c.base_path = nil }
+          expect(Petstore::Configuration.default.base_path).to eq('')
+        end
+      end
+    end
+  end
+
+  describe 'params_encoding in #build_request' do
+    let(:config) { Petstore::Configuration.new }
+    let(:api_client) { Petstore::ApiClient.new(config) }
+
+    it 'defaults to nil' do
+      expect(Petstore::Configuration.default.params_encoding).to eq(nil)
+      expect(config.params_encoding).to eq(nil)
+
+      request = api_client.build_request(:get, '/test')
+      expect(request.options[:params_encoding]).to eq(nil)
+    end
+
+    it 'can be customized' do
+      config.params_encoding = :multi
+      request = api_client.build_request(:get, '/test')
+      expect(request.options[:params_encoding]).to eq(:multi)
+    end
+  end
+
+  describe 'timeout in #build_request' do
+    let(:config) { Petstore::Configuration.new }
+    let(:api_client) { Petstore::ApiClient.new(config) }
+
+    it 'defaults to 0' do
+      expect(Petstore::Configuration.default.timeout).to eq(0)
+      expect(config.timeout).to eq(0)
+
+      request = api_client.build_request(:get, '/test')
+      expect(request.options[:timeout]).to eq(0)
+    end
+
+    it 'can be customized' do
+      config.timeout = 100
+      request = api_client.build_request(:get, '/test')
+      expect(request.options[:timeout]).to eq(100)
+    end
+  end
+
+  describe '#deserialize' do
+    it "handles Array<Integer>" do
+      api_client = Petstore::ApiClient.new
+      headers = { 'Content-Type' => 'application/json' }
+      response = double('response', headers: headers, body: '[12, 34]')
+      data = api_client.deserialize(response, 'Array<Integer>')
+      expect(data).to be_instance_of(Array)
+      expect(data).to eq([12, 34])
+    end
+
+    it 'handles Array<Array<Integer>>' do
+      api_client = Petstore::ApiClient.new
+      headers = { 'Content-Type' => 'application/json' }
+      response = double('response', headers: headers, body: '[[12, 34], [56]]')
+      data = api_client.deserialize(response, 'Array<Array<Integer>>')
+      expect(data).to be_instance_of(Array)
+      expect(data).to eq([[12, 34], [56]])
+    end
+
+    it 'handles Hash<String, String>' do
+      api_client = Petstore::ApiClient.new
+      headers = { 'Content-Type' => 'application/json' }
+      response = double('response', headers: headers, body: '{"message": "Hello"}')
+      data = api_client.deserialize(response, 'Hash<String, String>')
+      expect(data).to be_instance_of(Hash)
+      expect(data).to eq(:message => 'Hello')
+    end
+  end
+
+  describe "#object_to_hash" do
+    it 'ignores nils and includes empty arrays' do
+      # uncomment below to test object_to_hash for model
+      # api_client = Petstore::ApiClient.new
+      # _model = Petstore::ModelName.new
+      # update the model attribute below
+      # _model.id = 1
+      # update the expected value (hash) below
+      # expected = {id: 1, name: '', tags: []}
+      # expect(api_client.object_to_hash(_model)).to eq(expected)
+    end
+  end
+
+  describe '#build_collection_param' do
+    let(:param) { ['aa', 'bb', 'cc'] }
+    let(:api_client) { Petstore::ApiClient.new }
+
+    it 'works for csv' do
+      expect(api_client.build_collection_param(param, :csv)).to eq('aa,bb,cc')
+    end
+
+    it 'works for ssv' do
+      expect(api_client.build_collection_param(param, :ssv)).to eq('aa bb cc')
+    end
+
+    it 'works for tsv' do
+      expect(api_client.build_collection_param(param, :tsv)).to eq("aa\tbb\tcc")
+    end
+
+    it 'works for pipes' do
+      expect(api_client.build_collection_param(param, :pipes)).to eq('aa|bb|cc')
+    end
+
+    it 'works for multi' do
+      expect(api_client.build_collection_param(param, :multi)).to eq(['aa', 'bb', 'cc'])
+    end
+
+    it 'fails for invalid collection format' do
+      expect { api_client.build_collection_param(param, :INVALID) }.to raise_error(RuntimeError, 'unknown collection format: :INVALID')
+    end
+  end
+
+  describe '#json_mime?' do
+    let(:api_client) { Petstore::ApiClient.new }
+
+    it 'works' do
+      expect(api_client.json_mime?(nil)).to eq false
+      expect(api_client.json_mime?('')).to eq false
+
+      expect(api_client.json_mime?('application/json')).to eq true
+      expect(api_client.json_mime?('application/json; charset=UTF8')).to eq true
+      expect(api_client.json_mime?('APPLICATION/JSON')).to eq true
+
+      expect(api_client.json_mime?('application/xml')).to eq false
+      expect(api_client.json_mime?('text/plain')).to eq false
+      expect(api_client.json_mime?('application/jsonp')).to eq false
+    end
+  end
+
+  describe '#select_header_accept' do
+    let(:api_client) { Petstore::ApiClient.new }
+
+    it 'works' do
+      expect(api_client.select_header_accept(nil)).to be_nil
+      expect(api_client.select_header_accept([])).to be_nil
+
+      expect(api_client.select_header_accept(['application/json'])).to eq('application/json')
+      expect(api_client.select_header_accept(['application/xml', 'application/json; charset=UTF8'])).to eq('application/json; charset=UTF8')
+      expect(api_client.select_header_accept(['APPLICATION/JSON', 'text/html'])).to eq('APPLICATION/JSON')
+
+      expect(api_client.select_header_accept(['application/xml'])).to eq('application/xml')
+      expect(api_client.select_header_accept(['text/html', 'application/xml'])).to eq('text/html,application/xml')
+    end
+  end
+
+  describe '#select_header_content_type' do
+    let(:api_client) { Petstore::ApiClient.new }
+
+    it 'works' do
+      expect(api_client.select_header_content_type(nil)).to eq('application/json')
+      expect(api_client.select_header_content_type([])).to eq('application/json')
+
+      expect(api_client.select_header_content_type(['application/json'])).to eq('application/json')
+      expect(api_client.select_header_content_type(['application/xml', 'application/json; charset=UTF8'])).to eq('application/json; charset=UTF8')
+      expect(api_client.select_header_content_type(['APPLICATION/JSON', 'text/html'])).to eq('APPLICATION/JSON')
+      expect(api_client.select_header_content_type(['application/xml'])).to eq('application/xml')
+      expect(api_client.select_header_content_type(['text/plain', 'application/xml'])).to eq('text/plain')
+    end
+  end
+
+  describe '#sanitize_filename' do
+    let(:api_client) { Petstore::ApiClient.new }
+
+    it 'works' do
+      expect(api_client.sanitize_filename('sun')).to eq('sun')
+      expect(api_client.sanitize_filename('sun.gif')).to eq('sun.gif')
+      expect(api_client.sanitize_filename('../sun.gif')).to eq('sun.gif')
+      expect(api_client.sanitize_filename('/var/tmp/sun.gif')).to eq('sun.gif')
+      expect(api_client.sanitize_filename('./sun.gif')).to eq('sun.gif')
+      expect(api_client.sanitize_filename('..\sun.gif')).to eq('sun.gif')
+      expect(api_client.sanitize_filename('\var\tmp\sun.gif')).to eq('sun.gif')
+      expect(api_client.sanitize_filename('c:\var\tmp\sun.gif')).to eq('sun.gif')
+      expect(api_client.sanitize_filename('.\sun.gif')).to eq('sun.gif')
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/configuration_spec.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/configuration_spec.rb
new file mode 100644
index 00000000000..cdbd1001691
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/configuration_spec.rb
@@ -0,0 +1,42 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+require 'spec_helper'
+
+describe Petstore::Configuration do
+  let(:config) { Petstore::Configuration.default }
+
+  before(:each) do
+    # uncomment below to setup host and base_path
+    # require 'URI'
+    # uri = URI.parse("http://petstore.swagger.io/v2")
+    # Petstore.configure do |c|
+    #   c.host = uri.host
+    #   c.base_path = uri.path
+    # end
+  end
+
+  describe '#base_url' do
+    it 'should have the default value' do
+      # uncomment below to test default value of the base path
+      # expect(config.base_url).to eq("http://petstore.swagger.io/v2")
+    end
+
+    it 'should remove trailing slashes' do
+      [nil, '', '/', '//'].each do |base_path|
+        config.base_path = base_path
+        # uncomment below to test trailing slashes
+        # expect(config.base_url).to eq("http://petstore.swagger.io/v2")
+      end
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/models/array_alias_spec.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/models/array_alias_spec.rb
new file mode 100644
index 00000000000..39af6c1c60e
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/models/array_alias_spec.rb
@@ -0,0 +1,35 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+require 'spec_helper'
+require 'json'
+require 'date'
+
+# Unit tests for Petstore::ArrayAlias
+# Automatically generated by openapi-generator (https://openapi-generator.tech)
+# Please update as you see appropriate
+describe 'ArrayAlias' do
+  before do
+    # run before each test
+    @instance = Petstore::ArrayAlias.new
+  end
+
+  after do
+    # run after each test
+  end
+
+  describe 'test an instance of ArrayAlias' do
+    it 'should create an instance of ArrayAlias' do
+      expect(@instance).to be_instance_of(Petstore::ArrayAlias)
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/models/map_alias_spec.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/models/map_alias_spec.rb
new file mode 100644
index 00000000000..bb64ef4a24f
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/models/map_alias_spec.rb
@@ -0,0 +1,35 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+require 'spec_helper'
+require 'json'
+require 'date'
+
+# Unit tests for Petstore::MapAlias
+# Automatically generated by openapi-generator (https://openapi-generator.tech)
+# Please update as you see appropriate
+describe 'MapAlias' do
+  before do
+    # run before each test
+    @instance = Petstore::MapAlias.new
+  end
+
+  after do
+    # run after each test
+  end
+
+  describe 'test an instance of MapAlias' do
+    it 'should create an instance of MapAlias' do
+      expect(@instance).to be_instance_of(Petstore::MapAlias)
+    end
+  end
+end
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/spec_helper.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/spec_helper.rb
new file mode 100644
index 00000000000..6af194706df
--- /dev/null
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/spec/spec_helper.rb
@@ -0,0 +1,111 @@
+=begin
+#OpenAPI Extension generating aliases to maps and arrays as models
+
+#This specification shows how to generate aliases to maps and arrays as models.
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 5.0.0-SNAPSHOT
+
+=end
+
+# load the gem
+require 'petstore'
+
+# The following  was generated by the `rspec --init` command. Conventionally, all
+# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
+# The generated `.rspec` file contains `--require spec_helper` which will cause
+# this file to always be loaded, without a need to explicitly require it in any
+# files.
+#
+# Given that it is always loaded, you are encouraged to keep this file as
+# light-weight as possible. Requiring heavyweight dependencies from this file
+# will add to the boot time of your test suite on EVERY test run, even for an
+# individual file that may not need all of that loaded. Instead, consider making
+# a separate helper file that requires the additional dependencies and performs
+# the additional setup, and require it from the spec files that actually need
+# it.
+#
+# The `.rspec` file also contains a few flags that are not defaults but that
+# users commonly want.
+#
+# See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
+RSpec.configure do |config|
+  # rspec-expectations config goes here. You can use an alternate
+  # assertion/expectation library such as wrong or the stdlib/minitest
+  # assertions if you prefer.
+  config.expect_with :rspec do |expectations|
+    # This option will default to `true` in RSpec 4. It makes the `description`
+    # and `failure_message` of custom matchers include text for helper methods
+    # defined using `chain`, e.g.:
+    #     be_bigger_than(2).and_smaller_than(4).description
+    #     # => "be bigger than 2 and smaller than 4"
+    # ...rather than:
+    #     # => "be bigger than 2"
+    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
+  end
+
+  # rspec-mocks config goes here. You can use an alternate test double
+  # library (such as bogus or mocha) by changing the `mock_with` option here.
+  config.mock_with :rspec do |mocks|
+    # Prevents you from mocking or stubbing a method that does not exist on
+    # a real object. This is generally recommended, and will default to
+    # `true` in RSpec 4.
+    mocks.verify_partial_doubles = true
+  end
+
+# The settings below are suggested to provide a good initial experience
+# with RSpec, but feel free to customize to your heart's content.
+=begin
+  # These two settings work together to allow you to limit a spec run
+  # to individual examples or groups you care about by tagging them with
+  # `:focus` metadata. When nothing is tagged with `:focus`, all examples
+  # get run.
+  config.filter_run :focus
+  config.run_all_when_everything_filtered = true
+
+  # Allows RSpec to persist some state between runs in order to support
+  # the `--only-failures` and `--next-failure` CLI options. We recommend
+  # you configure your source control system to ignore this file.
+  config.example_status_persistence_file_path = "spec/examples.txt"
+
+  # Limits the available syntax to the non-monkey patched syntax that is
+  # recommended. For more details, see:
+  #   - http://rspec.info/blog/2012/06/rspecs-new-expectation-syntax/
+  #   - http://www.teaisaweso.me/blog/2013/05/27/rspecs-new-message-expectation-syntax/
+  #   - http://rspec.info/blog/2014/05/notable-changes-in-rspec-3/#zero-monkey-patching-mode
+  config.disable_monkey_patching!
+
+  # This setting enables warnings. It's recommended, but in some cases may
+  # be too noisy due to issues in dependencies.
+  config.warnings = true
+
+  # Many RSpec users commonly either run the entire suite or an individual
+  # file, and it's useful to allow more verbose output when running an
+  # individual spec file.
+  if config.files_to_run.one?
+    # Use the documentation formatter for detailed output,
+    # unless a formatter has already been configured
+    # (e.g. via a command-line flag).
+    config.default_formatter = 'doc'
+  end
+
+  # Print the 10 slowest examples and example groups at the
+  # end of the spec run, to help surface which specs are running
+  # particularly slow.
+  config.profile_examples = 10
+
+  # Run specs in random order to surface order dependencies. If you find an
+  # order dependency and want to debug it, you can fix the order by providing
+  # the seed, which is printed after each run.
+  #     --seed 1234
+  config.order = :random
+
+  # Seed global randomization in this process using the `--seed` CLI option.
+  # Setting this allows you to use `--seed` to deterministically reproduce
+  # test failures related to randomization by passing the same `--seed` value
+  # as the one that triggered the failure.
+  Kernel.srand config.seed
+=end
+end