Add java.RegisterRequiredBuildComponentsForTest function

Insulate tests that exercise code in the java package from having to
register the build components provided by the java package by providing
a single function that registers them all. This follows the pattern
currently used in the cc and rust packages.

This change is in preparation for switching the dex_bootjars singleton
from a singleton, which does not require a module definition in order
to be instantiated, to a singleton module which does. That will require
adding a module definition into java.GatherRequiredDepsForTest() and
this change ensures that the required components will have been
registered in every test.

Bug: 177892522
Test: m nothing
Change-Id: I6475db8240894947dd07c89a940a3e4f201aa598

java/dexpreopt_bootjars_test.go

@@ -52,7 +52,6 @@ func testDexpreoptBoot(t *testing.T, ruleFile string, expectedInputs, expectedOu
 	dexpreopt.SetTestGlobalConfig(config, dexpreoptConfig)
 
 	ctx := testContext(config)
-	RegisterDexpreoptBootJarsComponents(ctx)
 	run(t, ctx, config)
 
 	dexpreoptBootJars := ctx.SingletonForTests("dex_bootjars")

java/java_test.go

@@ -73,21 +73,10 @@ func testConfig(env map[string]string, bp string, fs map[string][]byte) android.
 func testContext(config android.Config) *android.TestContext {
 
 	ctx := android.NewTestArchContext(config)
-	RegisterJavaBuildComponents(ctx)
-	RegisterAppBuildComponents(ctx)
-	RegisterAppImportBuildComponents(ctx)
-	RegisterAppSetBuildComponents(ctx)
-	RegisterAARBuildComponents(ctx)
-	RegisterGenRuleBuildComponents(ctx)
-	RegisterRuntimeResourceOverlayBuildComponents(ctx)
-	RegisterSystemModulesBuildComponents(ctx)
+	RegisterRequiredBuildComponentsForTest(ctx)
 	ctx.RegisterModuleType("java_plugin", PluginFactory)
 	ctx.RegisterModuleType("filegroup", android.FileGroupFactory)
 	ctx.RegisterModuleType("python_binary_host", python.PythonBinaryHostFactory)
-	RegisterDocsBuildComponents(ctx)
-	RegisterStubsBuildComponents(ctx)
-	RegisterPrebuiltApisBuildComponents(ctx)
-	RegisterSdkLibraryBuildComponents(ctx)
 	ctx.PreArchMutators(android.RegisterDefaultsPreArchMutators)
 	ctx.PreArchMutators(android.RegisterComponentsMutator)
 

java/testing.go

@@ -95,6 +95,29 @@ func prebuiltApisFilesForLibs(apiLevels []string, sdkLibs []string) map[string][
 	return fs
 }
 
+// Register build components provided by this package that are needed by tests.
+//
+// In particular this must register all the components that are used in the `Android.bp` snippet
+// returned by GatherRequiredDepsForTest()
+func RegisterRequiredBuildComponentsForTest(ctx android.RegistrationContext) {
+	RegisterAARBuildComponents(ctx)
+	RegisterAppBuildComponents(ctx)
+	RegisterAppImportBuildComponents(ctx)
+	RegisterAppSetBuildComponents(ctx)
+	RegisterDexpreoptBootJarsComponents(ctx)
+	RegisterDocsBuildComponents(ctx)
+	RegisterGenRuleBuildComponents(ctx)
+	RegisterJavaBuildComponents(ctx)
+	RegisterPrebuiltApisBuildComponents(ctx)
+	RegisterRuntimeResourceOverlayBuildComponents(ctx)
+	RegisterSdkLibraryBuildComponents(ctx)
+	RegisterStubsBuildComponents(ctx)
+	RegisterSystemModulesBuildComponents(ctx)
+}
+
+// Gather the module definitions needed by tests that depend upon code from this package.
+//
+// Returns an `Android.bp` snippet that defines the modules that are needed by this package.
 func GatherRequiredDepsForTest() string {
 	var bp string