--- a/tests/run-tests.py	Tue Sep 02 12:11:36 2014 +0200
+++ b/tests/run-tests.py	Mon Sep 08 16:41:00 2014 +0200
@@ -60,6 +60,14 @@
 from xml.dom import minidom
 import unittest
 
+try:
+    if sys.version_info < (2, 7):
+        import simplejson as json
+    else:
+        import json
+except ImportError:
+    json = None
+
 processlock = threading.Lock()
 
 # subprocess._cleanup can race with any Popen.wait or Popen.poll on py24
@@ -186,6 +194,8 @@
              " (default: $%s or %d)" % defaults['timeout'])
     parser.add_option("--time", action="store_true",
         help="time how long each test takes")
+    parser.add_option("--json", action="store_true",
+                      help="store test result data in 'report.json' file")
     parser.add_option("--tmpdir", type="string",
         help="run tests in the given temporary directory"
              " (implies --keep-tmpdir)")
@@ -1419,6 +1429,37 @@
             finally:
                 xuf.close()
 
+        if self._runner.options.json:
+            if json is None:
+                raise ImportError("json module not installed")
+            jsonpath = os.path.join(self._runner._testdir, 'report.json')
+            fp = open(jsonpath, 'w')
+            try:
+                timesd = {}
+                for test, cuser, csys, real in result.times:
+                    timesd[test] = real
+
+                outcome = {}
+                for tc in result.successes:
+                    testresult = {'result': 'success',
+                                  'time': ('%0.3f' % timesd[tc.name])}
+                    outcome[tc.name] = testresult
+
+                for tc, err in sorted(result.faildata.iteritems()):
+                    testresult = {'result': 'failure',
+                                  'time': ('%0.3f' % timesd[tc])}
+                    outcome[tc] = testresult
+
+                for tc, reason in result.skipped:
+                    testresult = {'result': 'skip',
+                                  'time': ('%0.3f' % timesd[tc.name])}
+                    outcome[tc.name] = testresult
+
+                jsonout = json.dumps(outcome, sort_keys=True, indent=4)
+                fp.writelines(("testreport =", jsonout))
+            finally:
+                fp.close()
+
         self._runner._checkhglib('Tested')
 
         self.stream.writeln('# Ran %d tests, %d skipped, %d warned, %d failed.'

--- a/tests/test-run-tests.t	Tue Sep 02 12:11:36 2014 +0200
+++ b/tests/test-run-tests.t	Mon Sep 08 16:41:00 2014 +0200
@@ -369,3 +369,40 @@
   Skipped test-failure.t: blacklisted
   # Ran 0 tests, 2 skipped, 0 warned, 0 failed.
 
+test for --json
+==================
+
+  $ $TESTDIR/run-tests.py --with-hg=`which hg` --json
+  
+  --- $TESTTMP/test-failure.t
+  +++ $TESTTMP/test-failure.t.err
+  @@ -1,4 +1,4 @@
+     $ echo babar
+  -  rataxes
+  +  babar
+   This is a noop statement so that
+   this test is still more bytes than success.
+  
+  ERROR: test-failure.t output changed
+  !.s
+  Skipped test-skip.t: skipped
+  Failed test-failure.t: output changed
+  # Ran 2 tests, 1 skipped, 0 warned, 1 failed.
+  python hash seed: * (glob)
+  [1]
+
+  $ cat report.json
+  testreport ={
+      "test-failure.t": [\{] (re)
+          "result": "failure", 
+          "time": "\s*[\d\.]{5}" (re)
+      }, 
+      "test-skip.t": {
+          "result": "skip", 
+          "time": "\s*[\d\.]{5}" (re)
+      }, 
+      "test-success.t": [\{] (re)
+          "result": "success", 
+          "time": "\s*[\d\.]{5}" (re)
+      }
+  } (no-eol)