Add AadToken tests

Author: cmbrose

tests/Get-AadToken.Tests.ps1

@@ -0,0 +1,67 @@
+Get-Module cosmos-db | Remove-Module -Force
+Import-Module $PSScriptRoot\..\cosmos-db\cosmos-db.psm1 -Force
+
+InModuleScope cosmos-db {
+    Describe "Get-AadToken" {                    
+        BeforeAll {
+            $MOCK_TOKEN = @{
+                accessToken = "MOCK_TOKEN"
+                expires_on  = [System.DateTimeOffset]::UtcNow.AddHours(1).ToUnixTimeSeconds()
+            }
+
+            Mock Get-AadTokenWithoutCaching {
+                return $MOCK_TOKEN
+            }
+        }
+
+        BeforeEach {
+            # This is defined in the main module
+            $AAD_TOKEN_CACHE = @{}
+        }
+
+        It "Only calls the core logic once with caching enabled" {
+            Use-CosmosDbInternalFlag -EnableCaching $true
+
+            $key = Get-AadToken
+            $key | Should -Be $MOCK_TOKEN.accessToken | Out-Null
+
+            $key = Get-AadToken
+            $key | Should -Be $MOCK_TOKEN.accessToken | Out-Null
+
+            Assert-MockCalled Get-AadTokenWithoutCaching -Times 1 -Exactly
+        }
+
+        It "Calls the core logic for each call with caching disabled" {  
+            Use-CosmosDbInternalFlag -EnableCaching $false
+
+            $key1 = Get-AadToken
+            $key1 | Should -Be $MOCK_TOKEN.accessToken | Out-Null
+
+            $key2 = Get-AadToken
+            $key2 | Should -Be $MOCK_TOKEN.accessToken | Out-Null
+
+            Assert-MockCalled Get-AadTokenWithoutCaching -Times 2 -Exactly
+        }
+
+        It "Respects token expiration" {
+            Use-CosmosDbInternalFlag -EnableCaching $true
+
+            $MOCK_TOKEN = @{
+                accessToken = "MOCK_TOKEN"
+                expires_on  = [System.DateTimeOffset]::UtcNow.ToUnixTimeSeconds()
+            }
+
+            Mock Get-AadTokenWithoutCaching {
+                return $MOCK_TOKEN
+            }
+
+            $key1 = Get-AadToken
+            $key1 | Should -Be $MOCK_TOKEN.accessToken | Out-Null
+
+            $key2 = Get-AadToken
+            $key2 | Should -Be $MOCK_TOKEN.accessToken | Out-Null
+
+            Assert-MockCalled Get-AadTokenWithoutCaching -Times 2 -Exactly
+        }
+    }
+}