provider/aws: fix CheckDestroy for main_route_table_association tests

builtin/providers/aws/resource_aws_main_route_table_association_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/hashicorp/terraform/helper/resource"
 	"github.com/hashicorp/terraform/terraform"
 )
@@ -39,8 +40,28 @@ func TestAccAWSMainRouteTableAssociation_basic(t *testing.T) {
 }
 
 func testAccCheckMainRouteTableAssociationDestroy(s *terraform.State) error {
-	if len(s.RootModule().Resources) > 0 {
+	conn := testAccProvider.Meta().(*AWSClient).ec2conn
-		return fmt.Errorf("Expected all resources to be gone, but found: %#v", s.RootModule().Resources)
+
+	for _, rs := range s.RootModule().Resources {
+		if rs.Type != "aws_main_route_table_association" {
+			continue
+		}
+
+		mainAssociation, err := findMainRouteTableAssociation(
+			conn,
+			rs.Primary.Attributes["vpc_id"],
+		)
+		if err != nil {
+			// Verify the error is what we want
+			if ae, ok := err.(awserr.Error); ok && ae.Code() == "ApplicationDoesNotExistException" {
+				continue
+			}
+			return err
+		}
+
+		if mainAssociation != nil {
+			return fmt.Errorf("still exists")
+		}
 	}
 
 	return nil