Start adding tests for image resolution.

Add tests that show what we want image input strings to resolve to, so
we can test that behaviour.

builtin/providers/google/image_test.go

@@ -0,0 +1,61 @@
+package google
+
+import (
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/resource"
+)
+
+func TestAccComputeImage_resolveImage(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckComputeImageDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccComputeImage_basedondisk,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckComputeImageExists(
+						"google_compute_image.foobar", &image),
+				),
+			},
+		},
+	})
+	images := map[string]string{
+		"family/debian-8":                                                                                     "projects/debian-cloud/global/images/family/debian-8-jessie",
+		"projects/debian-cloud/global/images/debian-8-jessie-v20170110":                                       "projects/debian-cloud/global/images/debian-8-jessie-v20170110",
+		"debian-8-jessie":                                                                                     "projects/debian-cloud/global/images/family/debian-8-jessie",
+		"debian-8-jessie-v20170110":                                                                           "projects/debian-cloud/global/images/debian-8-jessie-v20170110",
+		"https://www.googleapis.com/compute/v1/projects/debian-cloud/global/images/debian-8-jessie-v20170110": "https://www.googleapis.com/compute/v1/projects/debian-cloud/global/images/debian-8-jessie-v20170110",
+
+		// TODO(paddy): we need private images/families here to actually test this
+		"global/images/my-private-image":         "global/images/my-private-image",
+		"global/images/family/my-private-family": "global/images/family/my-private-family",
+		"my-private-image":                       "global/images/my-private-image",
+		"my-private-family":                      "global/images/family/my-private-family",
+		"my-project/my-private-image":            "projects/my-project/global/images/my-private-image",
+		"my-project/my-private-family":           "projects/my-project/global/images/family/my-private-family",
+		"insert-URL-here":                        "insert-URL-here",
+	}
+	config := &Config{
+		Credentials: credentials,
+		Project:     project,
+		Region:      region,
+	}
+
+	err := config.loadAndValidate()
+	if err != nil {
+		t.Fatalf("Error loading config: %s\n", err)
+	}
+	for input, expectation := range images {
+		result, err := resolveImage(config, input)
+		if err != nil {
+			t.Errorf("Error resolving input %s to image: %+v\n", input, err)
+			continue
+		}
+		if result != expectation {
+			t.Errorf("Expected input '%s' to resolve to '%s', it resolved to '%s' instead.\n", input, expectation, result)
+			continue
+		}
+	}
+}

builtin/providers/google/resource_compute_disk.go

@@ -112,6 +112,7 @@ func resourceComputeDiskCreate(d *schema.ResourceData, meta interface{}) error {
 		}
 
 		disk.SourceImage = imageUrl
+		log.Printf("[DEBUG] Image name resolved to: %s", imageUrl)
 	}
 
 	if v, ok := d.GetOk("type"); ok {