[PowerShell] add more tests to powershell client (#12057)

* add more tests to powershell client

* update spec

* update method name

* add new file

samples/client/petstore/powershell/tests/Model/ArrayTest.Tests.ps1

@@ -0,0 +1,17 @@
+#
+# OpenAPI Petstore
+# This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: "" \
+# Version: 1.0.0
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+
+Describe -tag 'PSPetstore' -name 'PSArrayTest' {
+    Context 'PSArrayTest' {
+        It 'Initialize-PSArrayTest' {
+            # a simple test to create an object
+            #$NewObject = Initialize-PSArrayTest -ArrayOfString "TEST_VALUE" -ArrayArrayOfInteger "TEST_VALUE" -ArrayArrayOfModel "TEST_VALUE"
+            #$NewObject | Should -BeOfType ArrayTest
+            #$NewObject.property | Should -Be 0
+        }
+    }
+}