fix zone expand

google/resource_composer_environment.go

@@ -663,6 +663,9 @@ func expandComposerEnvironmentServiceAccount(v interface{}, d *schema.ResourceDa
 
 func expandComposerEnvironmentZone(v interface{}, d *schema.ResourceData, config *Config) (string, error) {
 	zone := v.(string)
+	if len(zone) == 0 {
+		return zone, nil
+	}
 	if !strings.Contains(zone, "/") {
 		project, err := getProject(d, config)
 		if err != nil {

google/resource_composer_environment_test.go

@@ -469,11 +469,11 @@ func testSweepComposerEnvironmentBuckets(config *Config) error {
 // but will not remove them when the Environment is deleted.
 //
 // Destroy test step for config with a network will fail unless we clean up the firewalls before.
-func testAccCheckClearComposerEnvironmentFirewalls(network string) resource.TestCheckFunc {
+func testAccCheckClearComposerEnvironmentFirewalls(networkName string) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		config := testAccProvider.Meta().(*Config)
 		config.Project = getTestProjectFromEnv()
-		network, err := config.clientCompute.Networks.Get(getTestProjectFromEnv(), network).Do()
+		network, err := config.clientCompute.Networks.Get(getTestProjectFromEnv(), networkName).Do()
 		if err != nil {
 			return err
 		}
@@ -486,6 +486,7 @@ func testAccCheckClearComposerEnvironmentFirewalls(network string) resource.Test
 
 		var allErrors error
 		for _, firewall := range foundFirewalls.Items {
+			log.Printf("[DEBUG] Deleting firewall %q for test-resource network %q", firewall.Name, network.Name)
 			op, err := config.clientCompute.Firewalls.Delete(config.Project, firewall.Name).Do()
 			if err != nil {
 				allErrors = multierror.Append(allErrors,