diff --git a/builtin/providers/docker/resource_docker_image_test.go b/builtin/providers/docker/resource_docker_image_test.go
index 81c508742..67c5317c2 100644
--- a/builtin/providers/docker/resource_docker_image_test.go
+++ b/builtin/providers/docker/resource_docker_image_test.go
@@ -7,6 +7,8 @@ import (
 	"github.com/hashicorp/terraform/helper/resource"
 )
 
+var contentDigestRegexp = regexp.MustCompile(`\A[A-Za-z0-9_\+\.-]+:[A-Fa-f0-9]+\z`)
+
 func TestAccDockerImage_basic(t *testing.T) {
 	resource.Test(t, resource.TestCase{
 		PreCheck:  func() { testAccPreCheck(t) },
@@ -15,7 +17,7 @@ func TestAccDockerImage_basic(t *testing.T) {
 			resource.TestStep{
 				Config: testAccDockerImageConfig,
 				Check: resource.ComposeTestCheckFunc(
-					resource.TestMatchResourceAttr("docker_image.foo", "latest", regexp.MustCompile(`\A[a-f0-9]{64}\z`)),
+					resource.TestMatchResourceAttr("docker_image.foo", "latest", contentDigestRegexp),
 				),
 			},
 		},
@@ -30,7 +32,7 @@ func TestAccDockerImage_private(t *testing.T) {
 			resource.TestStep{
 				Config: testAddDockerPrivateImageConfig,
 				Check: resource.ComposeTestCheckFunc(
-					resource.TestMatchResourceAttr("docker_image.foobar", "latest", regexp.MustCompile(`\A[a-f0-9]{64}\z`)),
+					resource.TestMatchResourceAttr("docker_image.foobar", "latest", contentDigestRegexp),
 				),
 			},
 		},