toBeCallable(); expect(null)->not->toBeCallable(); }); test('failures', function () { $hello = 5; expect($hello)->toBeCallable(); })->throws(ExpectationFailedException::class); test('failures with custom message', function () { $hello = 5; expect($hello)->toBeCallable('oh no!'); })->throws(ExpectationFailedException::class, 'oh no!'); test('not failures', function () { expect(function () { return 42; })->not->toBeCallable(); })->throws(ExpectationFailedException::class);