Use claim to simplify assertions

[Turbo87]

This PR introduces https://github.com/svartalf/rust-claim/ for our tests to replace our custom t!() macro and simplify/improve a few other assert!() usages.

t!() is certainly shorter than assert_ok!(), but I think the latter expresses the intent way better than the former. With t!() is was always thinking that this might have something to do with translations... 😅

r? @jtgeibel

[bors]

☔ The latest upstream changes (presumably #2954) made this pull request unmergeable. Please resolve the merge conflicts.

Note that reviewers usually do not review pull requests until merge conflicts are resolved! Once you resolve the conflicts, you should change the labels applied by bors to indicate that your PR is ready for review. Post this as a comment to change the labels:

@rustbot modify labels: +S-waiting-on-review -S-waiting-on-author

[bors]

☔ The latest upstream changes (presumably #2946) made this pull request unmergeable. Please resolve the merge conflicts.

Note that reviewers usually do not review pull requests until merge conflicts are resolved! Once you resolve the conflicts, you should change the labels applied by bors to indicate that your PR is ready for review. Post this as a comment to change the labels:

@rustbot modify labels: +S-waiting-on-review -S-waiting-on-author

[jtgeibel]

I especially like assert_some_eq!, LGTM!

@bors r+

[bors]

📌 Commit 03ad28b has been approved by jtgeibel

[bors]

⌛ Testing commit 03ad28b with merge 30bf5bd...

[bors]

☀️ Test successful - checks-travis
Approved by: jtgeibel
Pushing 30bf5bd to master...