pytest: fix comparing asserts

[ikonst]

The plugin adapts pytest's output of (in)equality assertions to the format expected by PyCharm's comparison tool. However it gets truncated values from pytest which makes the comparison mostly useless. This fix overrides the truncation(s), and further improves the comparison by making it multiline (for comparing complex structures).

• override pytest_assertrepr_compare to work around pytest's SafeRepr truncation
• enable verbose mode to disable pytest's truncation of lines
• reverse pytest's escaping of newlines (to enable multiline comparison in PyCharm)

[ikonst]

[ikonst]

(yay, didn't realize there's tests — will review the failures and fix)

[ikonst]

ping @shalupov

[shalupov]

service messages are limited in length. I'll ask TeamCity whats the current limitation.

[ikonst]

I was relying on this for local pytest invocations in PyCharm. If TeamCity imposes stricter limitations than local invocations, can they be told apart?

[shalupov]

I've checked, currently there are no known limits. Thanks for the PR