run-tests: add missing life-cycle methods on the example custom test result

A previous commit introduced `onStart` and `onEnd` methods on test result but
the one used in tests lacked those two methods. Fix it and add some output to
be sure they are called.

Differential Revision: https://phab.mercurial-scm.org/D3899

tests/basic_test_result.py

@@ -1,4 +1,4 b''
-from __future__ import print_function
+from __future__ import absolute_import, print_function
 
 import unittest
 
@@ -39,6 +39,12 b' class TestResult(unittest._TextTestResul'
     def addIgnore(self, test, reason):
         print("IGNORE!", test, reason)
 
+    def onStart(self, test):
+        print("ON_START!", test)
+
+    def onEnd(self):
+        print("ON_END!")
+
     def addOutputMismatch(self, test, ret, got, expected):
         return False
 

tests/test-run-tests.t

@@ -1252,8 +1252,10 b' Add support for external test formatter'
   $ CUSTOM_TEST_RESULT=basic_test_result $PYTHON $TESTDIR/run-tests.py --with-hg=`which hg` "$@" test-success.t test-failure.t
   
   # Ran 2 tests, 0 skipped, 0 failed.
+  ON_START! <__main__.TestSuite tests=[<__main__.TTest testMethod=test-failure.t>, <__main__.TTest testMethod=test-success.t>]>
   FAILURE! test-failure.t output changed
   SUCCESS! test-success.t
+  ON_END!
 
 Test reusability for third party tools
 ======================================