add ruby httpx echo api tests (#16729)

samples/client/echo_api/ruby-httpx/openapi_client.gemspec

@@ -0,0 +1,38 @@
+# -*- encoding: utf-8 -*-
+
+=begin
+#Echo Server API
+
+#Echo Server API
+
+The version of the OpenAPI document: 0.1.0
+Contact: team@openapitools.org
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 7.1.0-SNAPSHOT
+
+=end
+
+$:.push File.expand_path("../lib", __FILE__)
+require "openapi_client/version"
+
+Gem::Specification.new do |s|
+  s.name        = "openapi_client"
+  s.version     = OpenapiClient::VERSION
+  s.platform    = Gem::Platform::RUBY
+  s.authors     = ["OpenAPI-Generator"]
+  s.email       = ["team@openapitools.org"]
+  s.homepage    = "https://openapi-generator.tech"
+  s.summary     = "Echo Server API Ruby Gem"
+  s.description = "Echo Server API"
+  s.license     = "Unlicense"
+  s.required_ruby_version = ">= 2.7"
+
+  s.add_runtime_dependency 'httpx', '~> 1.0', '>= 1.0.0'
+
+  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