diff --git a/android/register.go b/android/register.go
index d79982a..86943f2 100644
--- a/android/register.go
+++ b/android/register.go
@@ -114,3 +114,43 @@
 	}
 	return ret
 }
+
+// Interface for registering build components.
+//
+// Provided to allow registration of build components to be shared between the runtime
+// and test environments.
+type RegistrationContext interface {
+	RegisterModuleType(name string, factory ModuleFactory)
+	RegisterSingletonType(name string, factory SingletonFactory)
+}
+
+// Used to register build components from an init() method, e.g.
+//
+// init() {
+//   RegisterBuildComponents(android.InitRegistrationContext)
+// }
+//
+// func RegisterBuildComponents(ctx android.RegistrationContext) {
+//   ctx.RegisterModuleType(...)
+//   ...
+// }
+//
+// Extracting the actual registration into a separate RegisterBuildComponents(ctx) function
+// allows it to be used to initialize test context, e.g.
+//
+//   ctx := android.NewTestContext()
+//   RegisterBuildComponents(ctx)
+var InitRegistrationContext RegistrationContext = initRegistrationContext{}
+
+// Make sure the TestContext implements RegistrationContext.
+var _ RegistrationContext = (*TestContext)(nil)
+
+type initRegistrationContext struct{}
+
+func (ctx initRegistrationContext) RegisterModuleType(name string, factory ModuleFactory) {
+	RegisterModuleType(name, factory)
+}
+
+func (ctx initRegistrationContext) RegisterSingletonType(name string, factory SingletonFactory) {
+	RegisterSingletonType(name, factory)
+}
diff --git a/apex/apex_test.go b/apex/apex_test.go
index b2d891d..1840900 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -303,14 +303,10 @@
 	ctx.RegisterModuleType("toolchain_library", cc.ToolchainLibraryFactory)
 	ctx.RegisterModuleType("prebuilt_etc", android.PrebuiltEtcFactory)
 	ctx.RegisterModuleType("sh_binary", android.ShBinaryFactory)
-	ctx.RegisterModuleType("android_app_certificate", java.AndroidAppCertificateFactory)
 	ctx.RegisterModuleType("filegroup", android.FileGroupFactory)
-	ctx.RegisterModuleType("java_library", java.LibraryFactory)
-	ctx.RegisterModuleType("java_import", java.ImportFactory)
+	java.RegisterJavaBuildComponents(ctx)
 	ctx.RegisterModuleType("java_system_modules", java.SystemModulesFactory)
-	ctx.RegisterModuleType("android_app", java.AndroidAppFactory)
-	ctx.RegisterModuleType("android_app_import", java.AndroidAppImportFactory)
-	ctx.RegisterModuleType("override_android_app", java.OverrideAndroidAppModuleFactory)
+	java.RegisterAppBuildComponents(ctx)
 
 	ctx.PreArchMutators(android.RegisterDefaultsPreArchMutators)
 	ctx.PreArchMutators(func(ctx android.RegisterMutatorsContext) {
diff --git a/java/aar.go b/java/aar.go
index e0bea5d..201e590 100644
--- a/java/aar.go
+++ b/java/aar.go
@@ -34,8 +34,12 @@
 }
 
 func init() {
-	android.RegisterModuleType("android_library_import", AARImportFactory)
-	android.RegisterModuleType("android_library", AndroidLibraryFactory)
+	RegisterAARBuildComponents(android.InitRegistrationContext)
+}
+
+func RegisterAARBuildComponents(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("android_library_import", AARImportFactory)
+	ctx.RegisterModuleType("android_library", AndroidLibraryFactory)
 }
 
 //
diff --git a/java/app.go b/java/app.go
index ae637fd..94f6bb1 100755
--- a/java/app.go
+++ b/java/app.go
@@ -33,18 +33,22 @@
 var supportedDpis = []string{"ldpi", "mdpi", "hdpi", "xhdpi", "xxhdpi", "xxxhdpi"}
 
 func init() {
-	android.RegisterModuleType("android_app", AndroidAppFactory)
-	android.RegisterModuleType("android_test", AndroidTestFactory)
-	android.RegisterModuleType("android_test_helper_app", AndroidTestHelperAppFactory)
-	android.RegisterModuleType("android_app_certificate", AndroidAppCertificateFactory)
-	android.RegisterModuleType("override_android_app", OverrideAndroidAppModuleFactory)
-	android.RegisterModuleType("override_android_test", OverrideAndroidTestModuleFactory)
-	android.RegisterModuleType("android_app_import", AndroidAppImportFactory)
-	android.RegisterModuleType("android_test_import", AndroidTestImportFactory)
+	RegisterAppBuildComponents(android.InitRegistrationContext)
 
 	initAndroidAppImportVariantGroupTypes()
 }
 
+func RegisterAppBuildComponents(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("android_app", AndroidAppFactory)
+	ctx.RegisterModuleType("android_test", AndroidTestFactory)
+	ctx.RegisterModuleType("android_test_helper_app", AndroidTestHelperAppFactory)
+	ctx.RegisterModuleType("android_app_certificate", AndroidAppCertificateFactory)
+	ctx.RegisterModuleType("override_android_app", OverrideAndroidAppModuleFactory)
+	ctx.RegisterModuleType("override_android_test", OverrideAndroidTestModuleFactory)
+	ctx.RegisterModuleType("android_app_import", AndroidAppImportFactory)
+	ctx.RegisterModuleType("android_test_import", AndroidTestImportFactory)
+}
+
 // AndroidManifest.xml merging
 // package splits
 
diff --git a/java/java.go b/java/java.go
index 052e06f..4c80ba7 100644
--- a/java/java.go
+++ b/java/java.go
@@ -34,24 +34,7 @@
 )
 
 func init() {
-	android.RegisterModuleType("java_defaults", DefaultsFactory)
-
-	android.RegisterModuleType("java_library", LibraryFactory)
-	android.RegisterModuleType("java_library_static", LibraryStaticFactory)
-	android.RegisterModuleType("java_library_host", LibraryHostFactory)
-	android.RegisterModuleType("java_binary", BinaryFactory)
-	android.RegisterModuleType("java_binary_host", BinaryHostFactory)
-	android.RegisterModuleType("java_test", TestFactory)
-	android.RegisterModuleType("java_test_helper_library", TestHelperLibraryFactory)
-	android.RegisterModuleType("java_test_host", TestHostFactory)
-	android.RegisterModuleType("java_import", ImportFactory)
-	android.RegisterModuleType("java_import_host", ImportFactoryHost)
-	android.RegisterModuleType("java_device_for_host", DeviceForHostFactory)
-	android.RegisterModuleType("java_host_for_device", HostForDeviceFactory)
-	android.RegisterModuleType("dex_import", DexImportFactory)
-
-	android.RegisterSingletonType("logtags", LogtagsSingleton)
-	android.RegisterSingletonType("kythe_java_extract", kytheExtractJavaFactory)
+	RegisterJavaBuildComponents(android.InitRegistrationContext)
 
 	// Register sdk member types.
 	android.RegisterSdkMemberType(&headerLibrarySdkMemberType{
@@ -71,6 +54,27 @@
 	})
 }
 
+func RegisterJavaBuildComponents(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("java_defaults", DefaultsFactory)
+
+	ctx.RegisterModuleType("java_library", LibraryFactory)
+	ctx.RegisterModuleType("java_library_static", LibraryStaticFactory)
+	ctx.RegisterModuleType("java_library_host", LibraryHostFactory)
+	ctx.RegisterModuleType("java_binary", BinaryFactory)
+	ctx.RegisterModuleType("java_binary_host", BinaryHostFactory)
+	ctx.RegisterModuleType("java_test", TestFactory)
+	ctx.RegisterModuleType("java_test_helper_library", TestHelperLibraryFactory)
+	ctx.RegisterModuleType("java_test_host", TestHostFactory)
+	ctx.RegisterModuleType("java_import", ImportFactory)
+	ctx.RegisterModuleType("java_import_host", ImportFactoryHost)
+	ctx.RegisterModuleType("java_device_for_host", DeviceForHostFactory)
+	ctx.RegisterModuleType("java_host_for_device", HostForDeviceFactory)
+	ctx.RegisterModuleType("dex_import", DexImportFactory)
+
+	ctx.RegisterSingletonType("logtags", LogtagsSingleton)
+	ctx.RegisterSingletonType("kythe_java_extract", kytheExtractJavaFactory)
+}
+
 func (j *Module) checkSdkVersion(ctx android.ModuleContext) {
 	if j.SocSpecific() || j.DeviceSpecific() ||
 		(j.ProductSpecific() && ctx.Config().EnforceProductPartitionInterface()) {
diff --git a/java/java_test.go b/java/java_test.go
index 49838c7..3252736 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -63,27 +63,12 @@
 func testContext() *android.TestContext {
 
 	ctx := android.NewTestArchContext()
-	ctx.RegisterModuleType("android_app", AndroidAppFactory)
-	ctx.RegisterModuleType("android_app_certificate", AndroidAppCertificateFactory)
-	ctx.RegisterModuleType("android_app_import", AndroidAppImportFactory)
-	ctx.RegisterModuleType("android_library", AndroidLibraryFactory)
-	ctx.RegisterModuleType("android_test", AndroidTestFactory)
-	ctx.RegisterModuleType("android_test_helper_app", AndroidTestHelperAppFactory)
-	ctx.RegisterModuleType("android_test_import", AndroidTestImportFactory)
-	ctx.RegisterModuleType("java_binary", BinaryFactory)
-	ctx.RegisterModuleType("java_binary_host", BinaryHostFactory)
-	ctx.RegisterModuleType("java_device_for_host", DeviceForHostFactory)
-	ctx.RegisterModuleType("java_host_for_device", HostForDeviceFactory)
-	ctx.RegisterModuleType("java_library", LibraryFactory)
-	ctx.RegisterModuleType("java_library_host", LibraryHostFactory)
-	ctx.RegisterModuleType("java_test", TestFactory)
-	ctx.RegisterModuleType("java_import", ImportFactory)
-	ctx.RegisterModuleType("java_import_host", ImportFactoryHost)
-	ctx.RegisterModuleType("java_defaults", DefaultsFactory)
+	RegisterJavaBuildComponents(ctx)
+	RegisterAppBuildComponents(ctx)
+	RegisterAARBuildComponents(ctx)
 	ctx.RegisterModuleType("java_system_modules", SystemModulesFactory)
 	ctx.RegisterModuleType("java_genrule", genRuleFactory)
 	ctx.RegisterModuleType("java_plugin", PluginFactory)
-	ctx.RegisterModuleType("dex_import", DexImportFactory)
 	ctx.RegisterModuleType("filegroup", android.FileGroupFactory)
 	ctx.RegisterModuleType("genrule", genrule.GenRuleFactory)
 	ctx.RegisterModuleType("droiddoc", DroiddocFactory)
@@ -92,8 +77,6 @@
 	ctx.RegisterModuleType("prebuilt_stubs_sources", PrebuiltStubsSourcesFactory)
 	ctx.RegisterModuleType("java_sdk_library", SdkLibraryFactory)
 	ctx.RegisterModuleType("java_sdk_library_import", sdkLibraryImportFactory)
-	ctx.RegisterModuleType("override_android_app", OverrideAndroidAppModuleFactory)
-	ctx.RegisterModuleType("override_android_test", OverrideAndroidTestModuleFactory)
 	ctx.RegisterModuleType("prebuilt_apis", PrebuiltApisFactory)
 	ctx.PreArchMutators(android.RegisterPrebuiltsPreArchMutators)
 	ctx.PreArchMutators(android.RegisterPrebuiltsPostDepsMutators)
diff --git a/sdk/testing.go b/sdk/testing.go
index 77ba2e6..3dc88c1 100644
--- a/sdk/testing.go
+++ b/sdk/testing.go
@@ -78,10 +78,8 @@
 	ctx.RegisterModuleType("package", android.PackageFactory)
 
 	// from java package
-	ctx.RegisterModuleType("android_app_certificate", java.AndroidAppCertificateFactory)
-	ctx.RegisterModuleType("java_defaults", java.DefaultsFactory)
-	ctx.RegisterModuleType("java_library", java.LibraryFactory)
-	ctx.RegisterModuleType("java_import", java.ImportFactory)
+	java.RegisterJavaBuildComponents(ctx)
+	java.RegisterAppBuildComponents(ctx)
 	ctx.RegisterModuleType("droidstubs", java.DroidstubsFactory)
 	ctx.RegisterModuleType("prebuilt_stubs_sources", java.PrebuiltStubsSourcesFactory)
 
diff --git a/sysprop/sysprop_test.go b/sysprop/sysprop_test.go
index 6ac3f4c..d44f4cf 100644
--- a/sysprop/sysprop_test.go
+++ b/sysprop/sysprop_test.go
@@ -56,8 +56,8 @@
 func testContext(config android.Config) *android.TestContext {
 
 	ctx := android.NewTestArchContext()
-	ctx.RegisterModuleType("android_app", java.AndroidAppFactory)
-	ctx.RegisterModuleType("java_library", java.LibraryFactory)
+	java.RegisterJavaBuildComponents(ctx)
+	java.RegisterAppBuildComponents(ctx)
 	ctx.RegisterModuleType("java_system_modules", java.SystemModulesFactory)
 	ctx.PreArchMutators(android.RegisterPrebuiltsPreArchMutators)
 	ctx.PreArchMutators(android.RegisterPrebuiltsPostDepsMutators)