Made junit coverage-dir take directory, not file.

build/android/pylib/junit/test_runner.py

Index: build/android/pylib/junit/test_runner.py
diff --git a/build/android/pylib/junit/test_runner.py b/build/android/pylib/junit/test_runner.py
index a97841264dfaf13e314bdd553e5dda3226cc610b..02dd405f7fcf0279a0cdb15231f16eb7eae5a27f 100644
--- a/build/android/pylib/junit/test_runner.py
+++ b/build/android/pylib/junit/test_runner.py
@@ -47,7 +47,10 @@ class JavaTestRunner(object):
       # Add JVM arguments.
       jvm_args = []
       if self._coverage_dir:
-        jvm_args.append('-Demma.coverage.out.file=%s' % self._coverage_dir)
+        if not os.path.isdir(self._coverage_dir):

[jbudorick, 2016/05/24 19:33:21]

nit: os.path.exists

although I'm not sure how either would work if coverage_dir exists but isn't a
directory

[BigBossZhiling, 2016/05/25 02:00:20]

I tested os.path.exists and os.path.isdir.
True
False
True

I guess here it should be isdir right?

[jbudorick, 2016/05/25 13:11:37]

Hah, yes, I know how they work in that sense.
To elaborate a bit:
 - I'm not sure how makedirs would react if self._coverage_dir exists but isn't
a directory. I suspect it'll throw an Exception of some kind. Your current
implementation will try that.
 - I'm not sure how emma would react if self._coverage_dir exists but isn't a
directory. I suspect it'll die, but again, I'm not sure.

This should probably do:

  if not os.path.exists(self._coverage_dir):
    os.makedirs(self._coverage_dir)
  elif not os.path.isdir(self._coverage_dir):
    # raise an Exception of some type
  jvm_args.append(...)

+          os.makedirs(self._coverage_dir)
+        jvm_args.append('-Demma.coverage.out.file=%s' % os.path.join(
+            self._coverage_dir, '%s.ec' % self._test_suite))
       if jvm_args:
         command.extend(['--jvm-args', '"%s"' % ' '.join(jvm_args)])