test: Create migration test for the mongodbatlas_cloud_user_team_assignment resource migration path. (#3553)

* Added migration test

* Fixed migration test

* Empty commit

* Changed usernames

* Changed usernames

* Fix

* Fix

* Enhanced test

* Comments

---------

Co-authored-by: Cristina Sánchez Sánchez <[email protected]>

Author: csanx

.github/workflows/acceptance-tests-runner.yml

@@ -616,6 +616,7 @@ jobs:
           MONGODB_ATLAS_TEAMS_IDS: ${{ inputs.mongodb_atlas_teams_ids }}
           MONGODB_ATLAS_PROJECT_OWNER_ID: ${{ inputs.mongodb_atlas_project_owner_id }}
           MONGODB_ATLAS_ORG_ID: ${{ inputs.mongodb_atlas_org_id }}
+          MONGODB_ATLAS_USERNAME: ${{ vars.MONGODB_ATLAS_USERNAME }}
           ACCTEST_PACKAGES: |
             ./internal/service/clouduserorgassignment
             ./internal/service/clouduserteamassignment

internal/service/clouduserteamassignment/resource_migration_test.go

@@ -1,12 +1,95 @@
 package clouduserteamassignment_test
 
 import (
+	"fmt"
+	"os"
 	"testing"
 
+	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
+	"github.com/mongodb/terraform-provider-mongodbatlas/internal/testutil/acc"
 	"github.com/mongodb/terraform-provider-mongodbatlas/internal/testutil/mig"
 )
 
+const (
+	resourceTeamName           = "mongodbatlas_team.test"
+	resourceTeamAssignmentName = "mongodbatlas_cloud_user_team_assignment.test"
+)
+
 func TestMigCloudUserTeamAssignmentRS_basic(t *testing.T) {
 	mig.SkipIfVersionBelow(t, "2.0.0") // when resource 1st released
 	mig.CreateAndRunTest(t, basicTestCase(t))
 }
+
+func TestMigCloudUserTeamAssignmentRS_migrationJourney(t *testing.T) {
+	var (
+		orgID    = os.Getenv("MONGODB_ATLAS_ORG_ID")
+		teamName = fmt.Sprintf("team-test-%s", acc.RandomName())
+		username = os.Getenv("MONGODB_ATLAS_USERNAME")
+	)
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:     func() { acc.PreCheckBasic(t); acc.PreCheckAtlasUsername(t) },
+		CheckDestroy: checkDestroy,
+		Steps: []resource.TestStep{
+			{
+				// NOTE: 'usernames' attribute (available v1.39.0, deprecated in v2.0.0) is used in this test in team resource,
+				// which may be removed in future versions. This could cause the test to break - keep for version tracking.
+				ExternalProviders: mig.ExternalProviders(),
+				Config:            configTeamWithUsernamesFirst(orgID, teamName, username),
+			},
+			{
+				ProtoV6ProviderFactories: acc.TestAccProviderV6Factories,
+				Config:                   configWithTeamAssignmentsSecond(orgID, teamName, username), // expected to see 1 import in the plan
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr(resourceTeamName, "name", teamName),
+
+					resource.TestCheckResourceAttrSet(resourceTeamAssignmentName, "user_id"),
+					resource.TestCheckResourceAttr(resourceTeamAssignmentName, "username", username),
+				),
+			},
+			mig.TestStepCheckEmptyPlan(configWithTeamAssignmentsSecond(orgID, teamName, username)),
+		},
+	})
+}
+
+// Step 1: Original configuration with usernames attribute
+func configTeamWithUsernamesFirst(orgID, teamName, username string) string {
+	return fmt.Sprintf(`
+	resource "mongodbatlas_team" "test" {
+		org_id    = %[2]q
+		name      = %[3]q
+		usernames = [%[1]q]
+	}
+	`, username, orgID, teamName)
+}
+
+// Step 2: Configuration with team assignments using import blocks
+
+// NOTE: Using static resource assignment instead of for_each with multiple usernames
+// due to a known limitation in Terraform's acceptance testing framework with indexed resources.
+// The actual migration using for_each works correctly (verified locally).
+func configWithTeamAssignmentsSecond(orgID, teamName, username string) string {
+	return fmt.Sprintf(`
+	resource "mongodbatlas_team" "test" {
+		org_id    = %[1]q
+		name      = %[2]q
+	}
+
+	data "mongodbatlas_team" "test" {
+		org_id = %[1]q
+		team_id = mongodbatlas_team.test.team_id
+	}
+ 
+	resource "mongodbatlas_cloud_user_team_assignment" "test" {
+		org_id   = %[1]q
+		team_id  = mongodbatlas_team.test.team_id
+		user_id  = data.mongodbatlas_team.test.users[0].id
+	}
+
+	import {
+		to = mongodbatlas_cloud_user_team_assignment.test
+		id = "%[1]s/${mongodbatlas_team.test.team_id}/${data.mongodbatlas_team.test.users[0].id}"
+	}
+
+	`, orgID, teamName)
+}