Add main site navigation tests for desktop and mobile views

[davehunt]

This replaces the following tests from https://github.com/mozilla/mcom-tests:

• test_about > test_navbar_links_are_visible
• test_about > test_navbar_link_destinations_are_correct
• test_about > test_navbar_link_urls_are_valid
• test_mozillabased > test_navbar_links_are_visible

The main differences are:

• These tests check the main navigation links from the home page instead of the about and mozilla-based pages. We could easily parameterise these tests if we wanted to run them from multiple initial pages.
• The tests these replace were checking the links were visible, destination URLs were correct, and destination URLs responded with an OK response code. The new tests click the links (would throw if they were not visible), and check the destination URL is accurate for the expected page.
• The new tests also check the navigation for small screens by restricting the viewport.

[davehunt]

@alexgibson r?

[alexgibson]

Is there a reason we need to check the height of the menu here? Technically this could change depending on the string/translation.

[davehunt]

Ah, yes! I'd love to have a better indication that the menu is showing. I can't use is_displayed because then it tries clicking while it's still animating. I could wait for the height to stop changing, but ideally I'd wait for something more concrete. Do you have any suggestions?

[alexgibson]

Looking at the code, we add aria-expanded="true" to the _toggle_locator element once the menu opens. Perhaps we could use this?

[davehunt]

It looks like this attribute is added before the menu is open, as this is failing for me in 2/5 tests.

[alexgibson]

I wonder if we can adjust the code here to make testing easier, I'll take a look

[alexgibson]

Opened a PR which should hopefully make things easier: #3577

[alexgibson]

@davehunt - re: sanity tests, given that these take some time to complete (and one link is also external), perhaps it would be better to have a single santity test that just opens/closes the mobile menu, but doesn't traverse all the links. Thoughts?

[davehunt]

re: sanity tests, given that these take some time to complete (and one link is also external), perhaps it would be better to have a single santity test that just opens/closes the mobile menu, but doesn't traverse all the links. Thoughts?

I agree that we should probably avoid depending on an external site for our sanity tests. Do we even need to check the donate menu item given that we're planning to introduce a much more thorough link checker in the near future? I'd suggest dropping the donate check from both tests, and marking just the mobile test as sanity.

[alexgibson]

I agree that we should probably avoid depending on an external site for our sanity tests. Do we even need to check the donate menu item given that we're planning to introduce a much more thorough link checker in the near future? I'd suggest dropping the donate check from both tests, and marking just the mobile test as sanity.

Ok, sounds reasonable to me 👍

[davehunt]

Rebased and ready for review again. Note that we need #3577 to land before we merge this, but after review I can squash and prepare for the merge.

[alexgibson]

LGTM r+ pending #3577

Let's squash & wait for the other PR to merge. Will give these tests a final run once that's in master 👍

[davehunt]

Squashed and rebased!

[alexgibson]

r+ 🍟