toHaveBeenNthCalledWith has a wrong test report when using objects #6614
Description
🐛 Bug Report
When used with objects or classes for parameters expectations, toHaveBeenNthCalledWith error messages report the wrong call argument. It reports the last call arguments as received arguments.
To Reproduce
This test using expect.toHaveBeenNthCalledWith with objects has a false failure report
class Bar {
constructor(toto) {
this.toto = toto;
}
}
function foo(mock) {
mock.titi(new Bar('a'));
mock.titi(new Bar('not b at all'));
mock.titi(new Bar('c'));
}
test('toHaveBeenNthCalledWith bad report', () => {
const mock = {
titi: jest.fn()
};
foo(mock);
expect(mock.titi).toHaveBeenNthCalledWith(1, new Bar('a'));
expect(mock.titi).toHaveBeenNthCalledWith(2, new Bar('b'));
expect(mock.titi).toHaveBeenNthCalledWith(3, new Bar('c'));
});The test fails because the second mock.titi call received new Bar('not b at all') instead of new Bar('b') as a parameter.
But the error messages says it was called with new Bar('c') which is the last call.
● toHaveBeenNthCalledWith bad report
expect(jest.fn()).toHaveBeenNthCalledWith(expected)
Expected mock function second call to have been called with:
{"toto": "b"}
as argument 1, but it was called with
{"toto": "c"}.
Difference:
- Expected
+ Received
Bar {
- "toto": "b",
+ "toto": "c",
}
18 |
19 | expect(mock.titi).toHaveBeenNthCalledWith(1, new Bar('a'));
> 20 | expect(mock.titi).toHaveBeenNthCalledWith(2, new Bar('b'));
| ^
21 | expect(mock.titi).toHaveBeenNthCalledWith(3, new Bar('c'));
22 | });
23 |
at Object.<anonymous>.test (src/report.test.js:20:21)
Expected behavior
I expect the test report to give the real argument the mock was called with.
Run npx envinfo --preset jest
npx envinfo --preset jest
npx: installed 1 in 1.606s
System:
OS: macOS High Sierra 10.13.4
CPU: x64 Intel(R) Core(TM) i5-7360U CPU @ 2.30GHz
Binaries:
Node: 8.10.0 - /usr/local/bin/node
Yarn: 1.5.1 - /opt/local/bin/yarn
npm: 6.1.0 - /usr/local/bin/npm
npmPackages:
jest: ^23.0.1 => 23.0.1