GoogleTest module is implicitly linked in Win64 Shipping runtime through RigLogic.uplugin

This came up as a EPS ticket where the user had conflicting GoogleTest version linked in (one from his library and one from UE).

This dependency on GoogleTest in shipping build is probably undesirable (also in development). This affecting Win64 and probably Mac & Linux. That the main reason for this bug report.  The test modules should probably be moved in separated plugin that are enabled on demand instead of being pulled in by default by other modules/plugins. Note that DNACalib.uplugin and GeneSplicer.uplugin also have the same dependencies on GoogleTest, but they are not included by default, so they are a bit less problematic, but their test should be moved in a test plugin too.

The module GoogleTest module in linked in the engine runtime through RigLogic.uplugin (module RigLogicLibTest). The RigLogic is pulled in by MetaHumanSDK.uplugin and this plugin is enabled by default, So the module GoogleTest is linked in when building Lyra/Win64 Shipping for example. Note also the Bridge.uplugin also add MetaHumanSDK.uplugin and Bridge is also enabled by default.

To verify, you can add the following snipped at the very bottom of E:\UE_5.7\Engine\Plugins\Animation\RigLogic\Source\RigLogicLibTest\Private\RigLogicLibTestSuite.cpp and build Lyra game in Win64/Shipping

#include "gtest/gtest.h"

//#error Included UNCOMMENT, IF THE CODE IS COMPILED, SHOULD GENERATE AN ERROR

class FSomeTest: public ::testing::EmptyTestEventListener
{
	virtual void OnTestStart(const ::testing::TestInfo& InTestInfo) override{}
	virtual void OnTestPartResult(const ::testing::TestPartResult& InTestPartResult) override{}
};

If you uncomment the #error, you will ensure the code is compile (it will trigger a build error) and if you comment it back, it will build and link, showing that GoogleTest is enabled.

Alternatively, you can add logs to  E:\UE_5.7\Engine\Source\ThirdParty\GoogleTest\GoogleTest.Build.cs to check when it adds GTest libraries to the build.