helper/resource: pass config when testing import

Previously having a config was mutually exclusive with running an import,
but we need to provide a config so that the provider is declared, or else
we can't actually complete the import in the future world where providers
are installed dynamically based on their declarations.

helper/resource/testing.go

@@ -400,15 +400,18 @@ func Test(t TestT, c TestCase) {
 		var err error
 		log.Printf("[WARN] Test: Executing step %d", i)
 
-		// Determine the test mode to execute
-		if step.Config != "" {
-			state, err = testStepConfig(opts, state, step)
-		} else if step.ImportState {
-			state, err = testStepImportState(opts, state, step)
-		} else {
+		if step.Config == "" && !step.ImportState {
 			err = fmt.Errorf(
 				"unknown test mode for step. Please see TestStep docs\n\n%#v",
 				step)
+		} else {
+			if step.ImportState {
+				// Can optionally set step.Config in addition to
+				// step.ImportState, to provide config for the import.
+				state, err = testStepImportState(opts, state, step)
+			} else {
+				state, err = testStepConfig(opts, state, step)
+			}
 		}
 
 		// If there was an error, exit

helper/resource/testing_import_state_test.go

@@ -40,6 +40,7 @@ func TestTest_importState(t *testing.T) {
 
 		Steps: []TestStep{
 			TestStep{
+				Config:           testConfigStrProvider,
 				ResourceName:     "test_instance.foo",
 				ImportState:      true,
 				ImportStateId:    "foo",
@@ -89,6 +90,7 @@ func TestTest_importStateFail(t *testing.T) {
 
 		Steps: []TestStep{
 			TestStep{
+				Config:           testConfigStrProvider,
 				ResourceName:     "test_instance.foo",
 				ImportState:      true,
 				ImportStateId:    "foo",
@@ -163,6 +165,7 @@ func TestTest_importStateDetectId(t *testing.T) {
 				Config: testConfigStr,
 			},
 			TestStep{
+				Config:           testConfigStr,
 				ResourceName:     "test_instance.foo",
 				ImportState:      true,
 				ImportStateCheck: checkFn,
@@ -236,6 +239,7 @@ func TestTest_importStateIdPrefix(t *testing.T) {
 				Config: testConfigStr,
 			},
 			{
+				Config:              testConfigStr,
 				ResourceName:        "test_instance.foo",
 				ImportState:         true,
 				ImportStateCheck:    checkFn,
@@ -309,6 +313,7 @@ func TestTest_importStateVerify(t *testing.T) {
 				Config: testConfigStr,
 			},
 			TestStep{
+				Config:            testConfigStr,
 				ResourceName:      "test_instance.foo",
 				ImportState:       true,
 				ImportStateVerify: true,
@@ -371,6 +376,7 @@ func TestTest_importStateVerifyFail(t *testing.T) {
 				Config: testConfigStr,
 			},
 			TestStep{
+				Config:            testConfigStr,
 				ResourceName:      "test_instance.foo",
 				ImportState:       true,
 				ImportStateVerify: true,

helper/resource/testing_test.go

@@ -619,10 +619,6 @@ func testProvider() *terraform.MockResourceProvider {
 	return mp
 }
 
-const testConfigStr = `
-resource "test_instance" "foo" {}
-`
-
 func TestTest_Main(t *testing.T) {
 	flag.Parse()
 	if *flagSweep == "" {
@@ -777,3 +773,11 @@ func TestTest_Main(t *testing.T) {
 func mockSweeperFunc(s string) error {
 	return nil
 }
+
+const testConfigStr = `
+resource "test_instance" "foo" {}
+`
+
+const testConfigStrProvider = `
+provider "test" {}
+`