Fix web-platform-tests#10026: add test execution time to wptreport.js…

…on format

tools/wptrunner/wptrunner/formatters.py

@@ -33,6 +33,10 @@ def find_or_create_test(self, data):
             }
         return self.raw_results[test_name]
 
+    def test_start(self, data):
+        test = self.find_or_create_test(data)
+        test["start_time"] = data["time"]
+
     def create_subtest(self, data):
         test = self.find_or_create_test(data)
         subtest_name = data["subtest"]
@@ -54,6 +58,8 @@ def test_status(self, data):
 
     def test_end(self, data):
         test = self.find_or_create_test(data)
+        start_time = test.pop("start_time")
+        test["duration"] = data["time"] - start_time
         test["status"] = data["status"]
         if "message" in data:
             test["message"] = data["message"]

tools/wptrunner/wptrunner/tests/test_formatters.py

@@ -0,0 +1,39 @@
+import json
+import sys
+import time
+from os.path import dirname, join
+from StringIO import StringIO
+
+from mozlog import handlers, structuredlog
+
+sys.path.insert(0, join(dirname(__file__), "..", ".."))
+
+from wptrunner.formatters import WptreportFormatter
+
+
+def test_wptreport_runtime(capfd):
+    # setup the logger
+    output = StringIO()
+    logger = structuredlog.StructuredLogger("test_a")
+    logger.add_handler(handlers.StreamHandler(output, WptreportFormatter()))
+
+    # output a bunch of stuff
+    logger.suite_start(["test-id-1"], run_info={})
+    logger.test_start("test-id-1")
+    time.sleep(0.125)
+    logger.test_end("test-id-1", "PASS")
+    logger.suite_end()
+
+    # check nothing got output to stdout/stderr
+    # (note that mozlog outputs exceptions during handling to stderr!)
+    captured = capfd.readouterr()
+    assert captured.out == ""
+    assert captured.err == ""
+
+    # check the actual output of the formatter
+    output.seek(0)
+    output_obj = json.load(output)
+    # be relatively lax in case of low resolution timers
+    # 62 is 0.125s = 125ms / 2 = 62ms (assuming int maths)
+    # this provides a margin of 62ms, sufficient for even DOS (55ms timer)
+    assert output_obj["results"][0]["duration"] >= 62