Various fixes for the fake docker client

* Properly return ImageNotFoundError
 * Support inject "Images" or "ImageInspects" and keep both in sync.
 * Remove the FakeDockerPuller and let FakeDockerClient subsumes its
   functinality. This reduces the overhead to maintain both objects.
 * Various small fixes and refactoring of the testing utils.

pkg/kubelet/dockershim/docker_container_test.go

@@ -23,6 +23,7 @@ import (
 	"testing"
 	"time"
 
+	dockertypes "github.com/docker/engine-api/types"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -102,14 +103,15 @@ func TestContainerStatus(t *testing.T) {
 	sConfig := makeSandboxConfig("foo", "bar", "1", 0)
 	labels := map[string]string{"abc.xyz": "foo"}
 	annotations := map[string]string{"foo.bar.baz": "abc"}
-	config := makeContainerConfig(sConfig, "pause", "iamimage", 0, labels, annotations)
+	imageName := "iamimage"
+	config := makeContainerConfig(sConfig, "pause", imageName, 0, labels, annotations)
 
 	var defaultTime time.Time
 	dt := defaultTime.UnixNano()
 	ct, st, ft := dt, dt, dt
 	state := runtimeapi.ContainerState_CONTAINER_CREATED
+	imageRef := DockerImageIDPrefix + imageName
 	// The following variables are not set in FakeDockerClient.
-	imageRef := DockerImageIDPrefix + ""
 	exitCode := int32(0)
 	var reason, message string
 
@@ -129,11 +131,14 @@ func TestContainerStatus(t *testing.T) {
 		Annotations: config.Annotations,
 	}
 
+	fDocker.InjectImages([]dockertypes.Image{{ID: imageName}})
+
 	// Create the container.
 	fClock.SetTime(time.Now().Add(-1 * time.Hour))
 	expected.CreatedAt = fClock.Now().UnixNano()
 	const sandboxId = "sandboxid"
 	id, err := ds.CreateContainer(sandboxId, config, sConfig)
+	assert.NoError(t, err)
 
 	// Check internal labels
 	c, err := fDocker.InspectContainer(id)