`Tools/TestWebKitAPI/Tests/WebKit/WKWebView/glib/TestInputMethodContext.cpp` has a mock `WebKitInputMethodContext` that all the input method API tests use. It presents the following gaps: 1. The mock does not implement the `notify_cursor_area` virtual function, so tests can't check what cursor area the input method is given, or whether it is given one at all. 2. The mock always reports the preedit caret at the end of the preedit. No test can exercise a caret inside the preedit, which is where several code paths differ. 3. The mock does not count notifications. A test can check that a notification arrived with the right values, but not that one failed to arrive. Missing notifications are a common failure mode for input methods.