Add new tests

PS/_Tests/Identity/Group/GetTfsGroupMember.Tests.ps1

@@ -2,7 +2,40 @@
 
 Describe (($MyInvocation.MyCommand.Name -split '\.')[-3]) {
 
-    Context 'Integration Tests' {
-        Write-Warning "$(Split-Path $PSCommandPath -Leaf): Test not implemented"
+    BeforeAll {
+        $collectionName = (Get-TfsTeamProjectCollection -Current).Name
+    }
+
+    Context '__AllParameterSets' {
+        # Get-TfsGroupMember
+        # [-Group] <Object>
+        # [[-Member] <string>]
+        # [-Recurse]
+        # [-Collection <Object>]
+        # [-Server <Object>] [<CommonParameters>]
+
+        It 'Should get all members of a server-level group' {
+            $members = Get-TfsGroupMember -Group '[TEAM FOUNDATION]\Enterprise Service Accounts' 
+            $members | Should -BeOfType [Microsoft.VisualStudio.Services.Identity.Identity]
+            $members.AccountName | Should -Be 'TeamFoundationService (TEAM FOUNDATION)'
+        }
+
+        It 'Should get all members of a collection-level group' {
+            $members = Get-TfsGroupMember -Group "[$collectionName]\Project Collection Service Accounts" 
+            $members | Should -BeOfType [Microsoft.VisualStudio.Services.Identity.Identity]
+            $members.AccountName | Should -Be 'Enterprise Service Accounts'
+        }
+
+        It 'Should get all members of a project-level group' {
+            $members = Get-TfsGroupMember -Group "[$tfsProject]\Endpoint Administrators"
+            $members | Should -BeOfType [Microsoft.VisualStudio.Services.Identity.Identity]
+            $members.AccountName | Should -Be 'Project Administrators'
+        }
+
+        It 'Should get all members of a group recursively' {
+            $members = Get-TfsGroupMember -Group "[$tfsProject]\Endpoint Administrators" -Recurse
+            $members | Should -BeOfType [Microsoft.VisualStudio.Services.Identity.Identity]
+            $members.AccountName | Sort-Object | Should -Be @('[email protected]', 'Project Administrators')
+        }
     } 
 }