[lit] Fail testing if a googletest executable crashes during test discovery

googletest formatted tests are discovered by running the test executable. 
Previously testing would silently succeed if the test executable crashed 
during the discovery process. Now testing fails with "error: unable to 
discover google-tests ..." if the test executable exits with a non-zero status.

llvm-svn: 280455

utils/lit/lit/formats/googletest.py

@@ -35,7 +35,8 @@ class GoogleTest(TestFormat):
               lines = lines.replace('\r', '')
             lines = lines.split('\n')
         except:
-            litConfig.error("unable to discover google-tests in %r" % path)
+            litConfig.error("unable to discover google-tests in %r: %s"
+                            % (path, sys.exc_info()[1]))
             raise StopIteration
 
         nested_tests = []

utils/lit/lit/util.py

@@ -65,10 +65,13 @@ def mkdir_p(path):
 
 def capture(args, env=None):
     """capture(command) - Run the given command (or argv list) in a shell and
-    return the standard output."""
+    return the standard output. Raises a CalledProcessError if the command
+    exits with a non-zero status."""
     p = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                          env=env)
     out,_ = p.communicate()
+    if p.returncode != 0:
+        raise subprocess.CalledProcessError(cmd=args, returncode=p.returncode)
     return convert_string(out)
 
 def which(command, paths = None):