Fixed an issue where xByText would call toString() on objects and only match on [object Object]

[Vannevelj]

Summary

This fixes the problem as described in testing-library/native-testing-library#121. In short, getByText and queryByText would not find a match when the <Text> component has a nested component inside of it. This was caused by calling toString() on all components it found, meaning something like an <Image> would result in [object Object].

A workaround would be to use a regex match for your text instead so you could decide that that is better than this proposed fix, although I would recommend detailing that somewhere as this isn't easy to debug.

Test plan

I've provided a few unit tests and made sure the code supports a scenario in an existing unit test. That being said, I'm not 100% confident that this change will behave as intended for all scenarios (i.e. we now explicitly take care of string and number -- are there other data types that should be included)?

[thymikee]

Is this anyhow related to #275?

[Vannevelj]

It's related but not the same. The issue I describe here works on a single level, the direct children: with this fix, the Text node and it's siblings are getting an improved string representation.

The issue described there works on descendants. If you want to fix that, you'd need to go down in the component tree and form a string representation of all components in it.

The big difference is that I consider a nested component as an empty string whereas in order to fix that issue, you would need to go into the nested component (recursively) and build up a string representation.

I thought it best to keep the change contained to one issue at first but it shouldn't be terribly hard to expand for his scenario. I wasn't quite sure either what the desired functionality was there so I didn't attempt to fix it.