Consider introducing `statecheck` support for Import test mode

[austinvalle]

terraform-plugin-testing version

v1.9.0

Use cases

terraform-plugin-testing currently supports a new method of asserting values in Terraform state during Config mode with the statecheck package and the (TestStep).ConfigStateChecks field.

The Import mode for testing also has the (TestStep).ImportStateCheck field for performing state checks after, see:

terraform-plugin-testing/helper/resource/testing_new_import_state.go

Lines 152 to 177 in 9501a02

	if step.ImportStateCheck != nil {
	logging.HelperResourceTrace(ctx, "Using TestStep ImportStateCheck")
	var states []*terraform.InstanceState
	for address, r := range importState.RootModule().Resources {
	if strings.HasPrefix(address, "data.") {
	continue
	}
	if r.Primary == nil {
	continue
	}
	is := r.Primary.DeepCopy() //nolint:staticcheck // legacy usage
	is.Ephemeral.Type = r.Type // otherwise the check function cannot see the type
	states = append(states, is)
	}
	logging.HelperResourceDebug(ctx, "Calling TestStep ImportStateCheck")
	if err := step.ImportStateCheck(states); err != nil {
	t.Fatal(err)
	}
	logging.HelperResourceDebug(ctx, "Called TestStep ImportStateCheck")
	}

Proposal

We could introduce a similar state check implementation to ConfigStateChecks, with a new field (TestStep).ImportStateChecks. This implementation should be equivalent to the Config mode, since they both use terraform show to grab the JSON state representation.

We could also consider adjusting these tests and our documentation to use the import block, where we would then switch to using the plancheck package for checking values.

References

• The random provider has some tests that use this step to extract state values during import: testing: Update acceptance tests to use new statecheck package and value comparers terraform-provider-random#599