Add test cases for Docker image name parsing and cleanup

The tests for Docker image name parsing are repetitive and do not
cover enough test cases.

Refactor the tests to use table testing and add additional test cases.

pkg/kubelet/kubelet_test.go

@@ -1157,29 +1157,25 @@ func TestGetContainerInfoOnNonExistContainer(t *testing.T) {
 	mockCadvisor.AssertExpectations(t)
 }
 
+var parseImageNameTests = []struct {
+	imageName string
+	name      string
+	tag       string
+}{
+	{"ubuntu", "ubuntu", ""},
+	{"ubuntu:2342", "ubuntu", "2342"},
+	{"ubuntu:latest", "ubuntu", "latest"},
+	{"foo/bar:445566", "foo/bar", "445566"},
+	{"registry.example.com:5000/foobar", "registry.example.com:5000/foobar", ""},
+	{"registry.example.com:5000/foobar:5342", "registry.example.com:5000/foobar", "5342"},
+	{"registry.example.com:5000/foobar:latest", "registry.example.com:5000/foobar", "latest"},
+}
+
 func TestParseImageName(t *testing.T) {
-	name, tag := parseImageName("ubuntu")
+	for _, tt := range parseImageNameTests {
-	if name != "ubuntu" || tag != "" {
+		name, tag := parseImageName(tt.imageName)
-		t.Fatal("Unexpected name/tag: %s/%s", name, tag)
+		if name != tt.name || tag != tt.tag {
-	}
+			t.Errorf("Expected name/tag: %s/%s, got %s/%s", tt.name, tt.tag, name, tag)
-
+		}
-	name, tag = parseImageName("ubuntu:2342")
-	if name != "ubuntu" || tag != "2342" {
-		t.Fatal("Unexpected name/tag: %s/%s", name, tag)
-	}
-
-	name, tag = parseImageName("foo/bar:445566")
-	if name != "foo/bar" || tag != "445566" {
-		t.Fatal("Unexpected name/tag: %s/%s", name, tag)
-	}
-
-	name, tag = parseImageName("registry.example.com:5000/foobar")
-	if name != "registry.example.com:5000/foobar" || tag != "" {
-		t.Fatal("Unexpected name/tag: %s/%s", name, tag)
-	}
-
-	name, tag = parseImageName("registry.example.com:5000/foobar:5342")
-	if name != "registry.example.com:5000/foobar" || tag != "5342" {
-		t.Fatal("Unexpected name/tag: %s/%s", name, tag)
 	}
 }