launcher: Add --dump-on-failure switch

When the test fails, it can be useful to have the log files dumped
to stdout.

https://bugzilla.gnome.org/show_bug.cgi?id=741092

validate/launcher/baseclasses.py

@@ -410,6 +410,19 @@ class Test(Loggable):
         self.last_change_ts = time.time()
         self.start_ts = time.time()
 
+    def _dump_log_file(self, logfile):
+        message = "Dumping contents of %s\n" % logfile
+        printc(message, Colors.FAIL)
+
+        with open(logfile, 'r') as fin:
+            print fin.read()
+
+    def _dump_log_files(self):
+        printc("Dumping log files on failure\n", Colors.FAIL)
+        self._dump_log_file(self.logfile)
+        for logfile in self.extra_logfiles:
+            self._dump_log_file(logfile)
+
     def test_end(self):
         self.kill_subprocess()
         self.thread.join()
@@ -421,6 +434,10 @@ class Test(Loggable):
 
         self.close_logfile()
 
+        if self.options.dump_on_failure:
+            if self.result is not Result.PASSED:
+                self._dump_log_files()
+
         return self.result
 
 

validate/launcher/main.py

@@ -422,6 +422,9 @@ Note that all testsuite should be inside python modules, so the directory should
                         action='store',
                         help="Defines the limit for which a test is considered as long (in seconds)."
                              " Note that 0 will enable all tests", type=int),
+    parser.add_argument("--dump-on-failure", dest="dump_on_failure",
+                        action="store_true", default=False,
+                        help="Dump logs to stdout when a test fails")
     parser.add_argument("-c", "--config", dest="config",
                         help="This is DEPRECATED, prefer using the testsuite format"
                         " to configure testsuites")