r/aws_rds_cluster_instance: Set db_subnet_group_name in state on read if available

[bflad]

Closes #2594

Previously, when checking instance db_subnet_group_name attribute when only set in cluster configuration or similarly for instance import:

make testacc TEST=./aws TESTARGS='-run=TestAccAWSRDSClusterInstance_namePrefix'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./aws -v -run=TestAccAWSRDSClusterInstance_namePrefix -timeout 120m
=== RUN   TestAccAWSRDSClusterInstance_namePrefix
--- FAIL: TestAccAWSRDSClusterInstance_namePrefix (644.43s)
	testing.go:503: Step 0 error: Check failed: Check 3/4 error: aws_rds_cluster_instance.test: Attribute 'db_subnet_group_name' not found
FAIL
exit status 1
FAIL	github.com/terraform-providers/terraform-provider-aws/aws	644.461s
make: *** [testacc] Error 1

Now:

make testacc TEST=./aws TESTARGS='-run=TestAccAWSRDSClusterInstance_namePrefix'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./aws -v -run=TestAccAWSRDSClusterInstance_namePrefix -timeout 120m
=== RUN   TestAccAWSRDSClusterInstance_namePrefix
--- PASS: TestAccAWSRDSClusterInstance_namePrefix (636.21s)
PASS
ok  	github.com/terraform-providers/terraform-provider-aws/aws	636.242s

[Ninir]

Hey @bflad

Thanks for the work! :)

$ make testacc TEST=./aws TESTARGS='-run=TestAccAWSRDSClusterInstance_'   

==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./aws -v -run=TestAccAWSRDSClusterInstance_ -timeout 120m
=== RUN   TestAccAWSRDSClusterInstance_importBasic
--- PASS: TestAccAWSRDSClusterInstance_importBasic (891.84s)
=== RUN   TestAccAWSRDSClusterInstance_basic
--- PASS: TestAccAWSRDSClusterInstance_basic (1645.59s)
=== RUN   TestAccAWSRDSClusterInstance_namePrefix
--- PASS: TestAccAWSRDSClusterInstance_namePrefix (904.81s)
=== RUN   TestAccAWSRDSClusterInstance_generatedName
--- PASS: TestAccAWSRDSClusterInstance_generatedName (679.15s)
=== RUN   TestAccAWSRDSClusterInstance_kmsKey
--- PASS: TestAccAWSRDSClusterInstance_kmsKey (776.97s)
=== RUN   TestAccAWSRDSClusterInstance_disappears
--- PASS: TestAccAWSRDSClusterInstance_disappears (721.54s)
=== RUN   TestAccAWSRDSClusterInstance_withInstanceEnhancedMonitor
--- PASS: TestAccAWSRDSClusterInstance_withInstanceEnhancedMonitor (794.71s)
PASS
ok  	github.com/terraform-providers/terraform-provider-aws/aws	6414.668s

[bflad]

This has been released in terraform-provider-aws version 1.7.0. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!