# Assert

In this section we verify that the [unit of code](https://blog.fiftywords.co/unit-of-code), effectively, produces the expected result for the simulated situation.

Only one [exit point](https://blog.fiftywords.co/exit-point) must be verified for each [unit test](https://blog.fiftywords.co/unit-test) and it's that [exit point](https://blog.fiftywords.co/exit-point) this section is focused on.

```ts
test("the airplane state should be FLYING after takeoff", () => {
  /// Arrange
  const fakeEngine: IEngine = new FakeEngine();
  const fakeFuelTank: ITank = new FakeTank();
  const airplane: Airplane = new Airplane(fakeEngine, fakeFuelTank);

  /// Act
  airplane.takeoff();

  /**
   * Notice that we clearly mark the Assert section
   * and we compare the test actual result with
   * the expected result
   */

  /// Assert
  assert(airplane.currentStatus, AirplaneStatus.FLYING);
});
```

[🇨🇴 Versión en Español](https://blog.cincuentapalabras.co/afirmar)