Add preparer for test to use AndroidMk

Bug: 181070625
Test: m nothing
Change-Id: I6b408d44e82d3bac6661bf6b54020c5c4051900e

android/androidmk.go

@@ -44,6 +44,14 @@ func RegisterAndroidMkBuildComponents(ctx RegistrationContext) {
 	ctx.RegisterSingletonType("androidmk", AndroidMkSingleton)
 }
 
+// Enable androidmk support.
+// * Register the singleton
+// * Configure that we are inside make
+var PrepareForTestWithAndroidMk = GroupFixturePreparers(
+	FixtureRegisterWithContext(RegisterAndroidMkBuildComponents),
+	FixtureModifyConfig(SetKatiEnabledForTests),
+)
+
 // Deprecated: Use AndroidMkEntriesProvider instead, especially if you're not going to use the
 // Custom function. It's easier to use and test.
 type AndroidMkDataProvider interface {