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