This run_test helper sets up a convention that allows
us to give really short tracebacks for errors, and
eventually we can have more control over running
individual tests. (The latter goal has some
complications, since we often intentionally leak
setup in tests.)
This allows us to reliably parse the error in code, rather than
attempt to parse the error text. Because the error text gets
translated into the user's language, this error-handling path
wasn't functioning at all for users using Zulip in any of the
seven non-English languages for which we had a translation for
this string.
Together with 709c3b50f which fixed a similar issue in a
different error-handling path, this fixes#5598.
Steve Howell
Tim Abbott
Rohitt Vashishtha
Priyank
Greg Price
Steve Howell