Assertions

With assertions you can verify that your application behaves like you expect.

exists and absent

We've already met exists, which checks that an element exists on the page. An assertion with exists passes if there is at least one element which matches.

Exists has a cousin absent, which does the opposite, checking that there is no matching element.

await Button('Submit').absent();

note

These assertion methods are equivalents of Jest's expect and Cypress' should. When refactoring your test with Interactors, you would replace those constructs with the interactors' assertion methods.

has and is

You can use has to check if a filter defined by the interactor matches. For example, the TextField interactor has a value filter which returns the current value of the text field. So to check that the value of the 'Username' field is 'Taylor', we could do somthing like this:

await TextField('Username').has({ value: 'Taylor' });

This first finds the username field, and then checks that its value is 'Taylor'. Just like with actions, if there are multiple 'Username' fields this will throw an error.

We could have written an assertion using exists as well:

await TextField('Username', { value: 'Taylor' }).exists();

But this is slightly different! If there were multiple 'Username' fields, one of which has the value 'Taylor', then has would throw an error, but exists would not!

Whether you use exists or has depends on the situation. Use has when you know that an element exists, and you want to make an assertion about it. Checking the value of a text field is a good example for when to use has. Use exists when you want to assert that an element exists.

The is() method is an alias of has(). There is absolutely no difference in the way it works, but you can use it to make your code more readable.

For instance, if we wanted to test if a text field is visible, has() would work perfectly fine; but writing the test using is() would read more like a sentence:

await TextField('Username').is({ visible: true });

Waiting

Just like with actions, assertions are always retried for a period of time. This ensures that we don't get random failures due to timing.

For example, if we're checking that a button is absent, we might write something like this:

await Button('Submit').absent();

If the button is still there, but it will disappear after a short period of time, the interactor will keep searching to check if the button is still there for a while. As soon as it disappears, the assertion passes. If the button does not disappear, then our assertion will eventually time out, and it will fail.