bonobomock

Troubleshooting

My test code doesn’t compile

• Incorrect explicit mock type — if you are not using auto, ensure the GMock<signature> type matches the function signature. For member functions, the first parameter is void* (non-const) or const void* (const). See Explicit Mock Object Types.

My test compiles but the mock doesn’t work

There are several common causes:

1. The function is inlined or optimized away

The compiler inlined the target function, so there is no entry point for BonoboMock to patch. The mock is installed without error but the original code still runs. See Limitations: Function inlining for details on why this happens and the available mitigations.

• Ensure you are using cmake-bonobomock-helper to build your test target — it sets compiler flags (e.g., -fno-inline) that reduce inlining.
• Apply bonobomock-optimization-macros around the function definition and add the source file to FILES_TO_RECOMPILE in your CMakeLists.txt.
• If optimization macros don’t help, move the test source to NON_PROD_ONLY_TEST_FILES in the call to the cmake-bonobomock-helper.

2. The wrong overload is being mocked

If the function you are mocking is overloaded, &Class::method may be selecting the wrong overload. You need to cast the function pointer to the specific signature you want to mock. See Mock Overloaded Functions for how to disambiguate.

3. Using BONOBO_MOCK on a virtual function (SunPro / C++03 only)

On SunPro or C++03, if the function you are mocking is virtual, you must use BONOBO_MOCK_VIRTUAL instead of BONOBO_MOCK. The two macros resolve the function’s address in memory differently — BONOBO_MOCK uses the function pointer directly, while BONOBO_MOCK_VIRTUAL resolves the actual implementation address through the vtable. Using the wrong macro may patch the wrong location, causing the mock to have no effect. See Mock Virtual Functions for details.

On Itanium ABI compilers (GCC, Clang) with C++11 or later, BONOBO_MOCK auto-detects virtual functions and resolves their addresses correctly, so this is not a concern.

My test works in low-optimization builds but not in optimized builds

This is almost always caused by function inlining. When building without optimization (e.g., -O0, as in CMake’s Debug build type), the compiler does not inline functions, so BonoboMock can patch every entry point. In optimized builds (e.g., -O2, as in CMake’s RelWithDebInfo or Release build types), the compiler may inline the function you are trying to mock — the mock is installed without error, but calls that were inlined at compile time bypass the patch entirely.

See section 1 above for how to resolve this.

bonobomock make current page writable error

This is a fatal runtime error from mprotect() failing inside BonoboMock’s patching logic. BonoboMock needs to make code pages writable to overwrite function entry points (see Internals), and the OS refused.

On SunPro or C++03, the most common cause is using BONOBO_MOCK on a virtual function instead of BONOBO_MOCK_VIRTUAL. When BONOBO_MOCK is used on a virtual function on these compilers, it may resolve to an invalid address (e.g., a vtable offset rather than an actual code address), and attempting to make that memory writable fails. Use BONOBO_MOCK_VIRTUAL instead — see Mock Virtual Functions. On Itanium ABI compilers (GCC, Clang) with C++11, BONOBO_MOCK handles virtual functions correctly and this error has a different cause — check that the function address is valid and that the binary has not been stripped.

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