helper/resource: make id-only check opt-in

As I've been working through the resources, I'm finding that a lot are
going to need some serious work. Given we have hundreds, I think it
might be prudent to make this opt-in for now and we can revisit
automatic/opt-out at some future point.

Importability will likely be opt-in it appears so this will match up
with that.

helper/resource/testing.go

@@ -66,15 +66,12 @@ type TestCase struct {
 	// refreshed with only an ID to result in the same attributes.
 	// This validates completeness of Refresh.
 	//
-	// DisableIDRefresh, if true, willl not do the id-only refresh test.
-	//
 	// IDRefreshName is the name of the resource to check. This will
 	// default to the first non-nil primary resource in the state.
 	//
 	// IDRefreshIgnore is a list of configuration keys that will be ignored.
-	DisableIDRefresh bool
+	IDRefreshName   string
-	IDRefreshName    string
+	IDRefreshIgnore []string
-	IDRefreshIgnore  []string
 }
 
 // TestStep is a single apply sequence of a test, done within the
@@ -163,6 +160,7 @@ func Test(t TestT, c TestCase) {
 
 	// Go through each step and run it
 	var idRefreshCheck *terraform.ResourceState
+	idRefresh := c.IDRefreshName != ""
 	errored := false
 	for i, step := range c.Steps {
 		var err error
@@ -177,24 +175,15 @@ func Test(t TestT, c TestCase) {
 
 		// If we've never checked an id-only refresh and our state isn't
 		// empty, find the first resource and test it.
-		if !c.DisableIDRefresh && idRefreshCheck == nil && !state.Empty() {
+		if idRefresh && idRefreshCheck == nil && !state.Empty() {
 			// Find the first non-nil resource in the state
 			for _, m := range state.Modules {
 				if len(m.Resources) > 0 {
-					if c.IDRefreshName != "" {
+					if v, ok := m.Resources[c.IDRefreshName]; ok {
-						if v, ok := m.Resources[c.IDRefreshName]; ok {
+						idRefreshCheck = v
-							idRefreshCheck = v
-						}
-
-						break
 					}
 
-					for _, v := range m.Resources {
+					break
-						if v != nil && v.Primary != nil {
-							idRefreshCheck = v
-							break
-						}
-					}
 				}
 			}
 
@@ -219,7 +208,7 @@ func Test(t TestT, c TestCase) {
 	}
 
 	// If we never checked an id-only refresh, it is a failure.
-	if !c.DisableIDRefresh {
+	if idRefresh {
 		if !errored && len(c.Steps) > 0 && idRefreshCheck == nil {
 			t.Error("ID-only refresh check never ran.")
 		}

helper/resource/testing_test.go

@@ -125,6 +125,7 @@ func TestTest_idRefresh(t *testing.T) {
 
 	mt := new(mockT)
 	Test(mt, TestCase{
+		IDRefreshName: "test_instance.foo",
 		Providers: map[string]terraform.ResourceProvider{
 			"test": mp,
 		},
@@ -197,47 +198,6 @@ func TestTest_idRefreshCustomName(t *testing.T) {
 	}
 }
 
-func TestTest_idRefreshDisable(t *testing.T) {
-	mp := testProvider()
-	mp.DiffReturn = nil
-
-	mp.ApplyFn = func(
-		info *terraform.InstanceInfo,
-		state *terraform.InstanceState,
-		diff *terraform.InstanceDiff) (*terraform.InstanceState, error) {
-		if !diff.Destroy {
-			return &terraform.InstanceState{
-				ID: "foo",
-			}, nil
-		}
-
-		return nil, nil
-	}
-
-	var refreshCount int32
-	mp.RefreshFn = func(*terraform.InstanceInfo, *terraform.InstanceState) (*terraform.InstanceState, error) {
-		atomic.AddInt32(&refreshCount, 1)
-		return &terraform.InstanceState{ID: "foo"}, nil
-	}
-
-	mt := new(mockT)
-	Test(mt, TestCase{
-		DisableIDRefresh: true,
-		Providers: map[string]terraform.ResourceProvider{
-			"test": mp,
-		},
-		Steps: []TestStep{
-			TestStep{
-				Config: testConfigStr,
-			},
-		},
-	})
-
-	if mt.failed() {
-		t.Fatal("test failed")
-	}
-}
-
 func TestTest_idRefreshFail(t *testing.T) {
 	// Refresh count should be 3:
 	//   1.) initial Ref/Plan/Apply
@@ -278,6 +238,7 @@ func TestTest_idRefreshFail(t *testing.T) {
 
 	mt := new(mockT)
 	Test(mt, TestCase{
+		IDRefreshName: "test_instance.foo",
 		Providers: map[string]terraform.ResourceProvider{
 			"test": mp,
 		},