SF: Fix sffakehwc_test setup

registerAsService requires TREBLE_TESTING_OVERRIDE to be set.

Bug: 123530318
Test: sffakehwc_test runs (though some test cases fail)
Change-Id: I3e88844f7590f7b65be7c85f6802cf7aa349243c
diff --git a/services/surfaceflinger/tests/fakehwc/FakeComposerUtils.cpp b/services/surfaceflinger/tests/fakehwc/FakeComposerUtils.cpp
index 51956ec..4d21468 100644
--- a/services/surfaceflinger/tests/fakehwc/FakeComposerUtils.cpp
+++ b/services/surfaceflinger/tests/fakehwc/FakeComposerUtils.cpp
@@ -167,7 +167,9 @@
     }
     // TODO: Try registering the mock as the default service instead.
     property_set("debug.sf.hwc_service_name", "mock");
-    // This allows the SurfaceFlinger to load a HIDL service not listed in manifest files.
+
+    // This allows tests/SF to register/load a HIDL service not listed in manifest files.
+    setenv("TREBLE_TESTING_OVERRIDE", "true", true);
     property_set("debug.sf.treble_testing_override", "true");
 }
 
diff --git a/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp b/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp
index 093bcf5..c949d7c 100644
--- a/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp
+++ b/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp
@@ -171,7 +171,7 @@
     mMockComposer = new MockComposerClient;
     sp<ComposerClient> client = new ComposerClient(mMockComposer);
     mFakeService = new FakeComposerService(client);
-    (void)mFakeService->registerAsService("mock");
+    ASSERT_EQ(android::OK, mFakeService->registerAsService("mock"));
 
     android::hardware::ProcessState::self()->startThreadPool();
     android::ProcessState::self()->startThreadPool();