Bug 1338534 - [mozlog] Log message and stack for failures when using pytest-mozlog with pytest-xdist. r=ahal

When using pytest-xdist to run tests in parallel, failures are serialised as strings. This means we're unable to reliably extract the message and line number, so instead we log the stack and the message as the serialised string result.

MozReview-Commit-ID: 6vrEjBtkXK8

--HG--
extra : rebase_source : f337653f90cbbe6b1972b7d1e5e1a222c0a4604f

testing/mozbase/mozlog/mozlog/pytest_mozlog/plugin.py

@@ -84,9 +84,13 @@ class MozLog(object):
                 status = 'FAIL'
         elif report.failed:
             status = 'FAIL' if report.when == 'call' else 'ERROR'
-            crash = report.longrepr.reprcrash  # here longrepr is a ReprExceptionInfo
-            message = "{0} (line {1})".format(crash.message, crash.lineno)
-            stack = report.longrepr.reprtraceback
+            try:
+                crash = report.longrepr.reprcrash  # here longrepr is a ReprExceptionInfo
+                message = "{0} (line {1})".format(crash.message, crash.lineno)
+                stack = report.longrepr.reprtraceback
+            except AttributeError:
+                # When using pytest-xdist, longrepr is serialised as a str
+                message = stack = report.longrepr
         elif report.skipped:  # indicates true skip
             status = expected = 'SKIP'
             message = report.longrepr[-1]  # here longrepr is a tuple (file, lineno, reason)