Take desktop screenshots after test failures in test_runner.py.

ios/build/bots/scripts/test_runner.py

Index: ios/build/bots/scripts/test_runner.py
diff --git a/ios/build/bots/scripts/test_runner.py b/ios/build/bots/scripts/test_runner.py
index 0449975a659e57736ed07c701bab49faf2e297c7..c356109fb1fc787885c5fbc74a439f7be463decf 100644
--- a/ios/build/bots/scripts/test_runner.py
+++ b/ios/build/bots/scripts/test_runner.py
@@ -288,6 +288,7 @@ class TestRunner(object):
         stderr=subprocess.STDOUT,
     )
 
+    failed_test_count = len(parser.FailedTests())
     while True:
       line = proc.stdout.readline()
       if not line:
@@ -297,6 +298,12 @@ class TestRunner(object):
       print line
       sys.stdout.flush()
 
+      # If there is a new test failure, take screenshot of desktop. This can
+      # help with debugging failures on the bots.
+      if len(parser.FailedTests()) > failed_test_count:
+        failed_test_count = len(parser.FailedTests())
+        self.screenshot_desktop()

[smut, 2017/03/22 22:46:54]

parser is reinitialized every time (lines 279-282) so on line 291
failed_test_count will always be zero. Line 301 can then be "if
parser.FailedTests():".

[baxley, 2017/03/22 23:24:39]

Done.

[baxley, 2017/03/23 13:54:19]

I don't think this works. parser is initialized outside of the while loop, so
once there is a test failure then a screenshot is taken for every line of
output. When running ios-simulator try job it fails due to not enough space. I
reverted to the mode where I count failures and only take a screenshot when it
increases.

Is the documents directory cleaned up after each suite on simulator (I thought
it was, but want to confirm). This will store on the order of 1MB per
screenshot.

+
     proc.wait()
     sys.stdout.flush()