istanbuljs does not report the code coverage properly in case of callback function like in this example:
obj.removeEventListener('unload', () => this.dispose());
test case:
it('dispose call removeEventListener', async() => {
spyOn(obj, 'removeEventListener');
obj.dispose();
expect(obj['removeEventListener']).toHaveBeenCalledTimes(1);
expect(obj['removeEventListener']).toHaveBeenCalledWith('unload', jasmine.any(Function));
});
I just saved in a separated function the callback function to fix the istanbuljs code coverage report.
obj.callDispose = () => { this.dispose() }; // obj.dispose();
obj.removeEventListener('unload', this.callDispose); // obj.callDispose
test case:
it('dispose call removeEventListener', async() => {
spyOn(obj, 'removeEventListener');
obj.dispose();
expect(obj['removeEventListener']).toHaveBeenCalledTimes(1);
expect(obj['removeEventListener']).toHaveBeenCalledWith('unload', obj.callDispose);
});