Enhance integration test setup and cleanup steps

Expanded the BeforeAll and AfterAll blocks in the integration test style guide to include detailed setup and cleanup procedures for availability groups and databases. Added comments for clarity and ensured proper handling of test artifacts and PowerShell parameter defaults.

Author: potatoqualitee

.aitools/prompts/style.md

@@ -32,12 +32,59 @@ Describe $CommandName -Tag UnitTests {
 
 Describe $CommandName -Tag IntegrationTests {
     BeforeAll {
-        $PSDefaultParameterValues["*-Dba*:EnableException"] = $true
+        # We want to run all commands in the BeforeAll block with EnableException to ensure that the test fails if the setup fails.
+        $PSDefaultParameterValues['*-Dba*:EnableException'] = $true
+
+        # For all the backups that we want to clean up after the test, we create a directory that we can delete at the end.
+        # Other files can be written there as well, maybe we change the name of that variable later. But for now we focus on backups.
+        $backupPath = "$($TestConfig.Temp)\$CommandName-$(Get-Random)"
+        $null = New-Item -Path $backupPath -ItemType Directory
+
+        # Explain what needs to be set up for the test:
+        # To add a database to an availablity group, we need an availability group and a database that has been backed up.
+        # For negative tests, we need a database without a backup and a non existing database.
+
+        # Set variables. They are available in all the It blocks.
+        $agName                  = "addagdb_group"
+        $existingDbWithBackup    = "dbWithBackup"
+        $existingDbWithoutBackup = "dbWithoutBackup"
+        $nonexistingDb           = "dbdoesnotexist"
+
+        # Create the objects.
+        $splat = @{
+            Primary      = $TestConfig.instance3
+            Name         = $agName
+            ClusterType  = "None"
+            FailoverMode = "Manual"
+            Certificate  = "dbatoolsci_AGCert"
+        }
+        $null = New-DbaAvailabilityGroup @splat
+
+        $null = New-DbaDatabase -SqlInstance $TestConfig.instance3 -Name $existingDbWithBackup
+        $null = Backup-DbaDatabase -SqlInstance $TestConfig.instance3 -Database $existingDbWithBackup -Path $backupPath
+
+        $null = New-DbaDatabase -SqlInstance $TestConfig.instance3 -Name $existingDbWithoutBackup
+
+        # We want to run all commands outside of the BeforeAll block without EnableException to be able to test for specific warnings.
+        $PSDefaultParameterValues.Remove('*-Dba*:EnableException')
     }
 
     AfterAll {
-        $PSDefaultParameterValues.Remove("*-Dba*:EnableException")
+        # We want to run all commands in the AfterAll block with EnableException to ensure that the test fails if the cleanup fails.
+        $PSDefaultParameterValues['*-Dba*:EnableException'] = $true
+
+        # Cleanup all created object.
+        $null = Remove-DbaAvailabilityGroup -SqlInstance $TestConfig.instance3 -AvailabilityGroup $agName
+        $null = Get-DbaEndpoint -SqlInstance $TestConfig.instance3 -Type DatabaseMirroring | Remove-DbaEndpoint
+        $null = Remove-DbaDatabase -SqlInstance $TestConfig.instance3 -Database $existingDbWithBackup, $existingDbWithoutBackup
+
+        # Remove the backup directory.
+        Remove-Item -Path $backupPath -Recurse
+
+        # As this is the last block we do not need to reset the $PSDefaultParameterValues.
     }
+
+    # Integration tests here
 }
 ```