run-tests: refactor filtering logic for --retest flag

How I got to this:
While re-running failed tests using --retest I noticed that the output:
	"running x tests using y parallel processes".
was not actually correct, because x was the total number of tests present
in the directory, but it should be the number of failed tests. Although
it would run only the failed tests and later will say that remaining tests
were skipped.
Changes in test files reflect the fixed behaviour.

This patch change and move the logic for filtering failed test for
--retest option and make sure that we create instances of
class Test only for the tests we need to run.

As mentioned in the deleted text (in this patch itself) the logic
for --retest should be outside of TestSuite.

Differential Revision: https://phab.mercurial-scm.org/D8938

tests/run-tests.py

@@ -2336,7 +2336,6 b' class TestSuite(unittest.TestSuite):'
         jobs=1,
         whitelist=None,
         blacklist=None,
-        retest=False,
         keywords=None,
         loop=False,
         runs_per_test=1,
@@ -2364,9 +2363,6 b' class TestSuite(unittest.TestSuite):'
         backwards compatible behavior which reports skipped tests as part
         of the results.
 
-        retest denotes whether to retest failed tests. This arguably belongs
-        outside of TestSuite.
-
         keywords denotes key words that will be used to filter which tests
         to execute. This arguably belongs outside of TestSuite.
 
@@ -2377,7 +2373,6 b' class TestSuite(unittest.TestSuite):'
         self._jobs = jobs
         self._whitelist = whitelist
         self._blacklist = blacklist
-        self._retest = retest
         self._keywords = keywords
         self._loop = loop
         self._runs_per_test = runs_per_test
@@ -2407,10 +2402,6 b' class TestSuite(unittest.TestSuite):'
                     result.addSkip(test, 'blacklisted')
                     continue
 
-                if self._retest and not os.path.exists(test.errpath):
-                    result.addIgnore(test, 'not retesting')
-                    continue
-
                 if self._keywords:
                     with open(test.path, 'rb') as f:
                         t = f.read().lower() + test.bname.lower()
@@ -3253,6 +3244,22 b' class TestRunner(object):'
                     tests.append({'path': t})
             else:
                 tests.append({'path': t})
+
+        if self.options.retest:
+            retest_args = []
+            for test in tests:
+                if 'case' in test:
+                    # for multiple dimensions test cases
+                    casestr = b'#'.join(test['case'])
+                    errpath = b'%s#%s.err' % (test['path'], casestr)
+                else:
+                    errpath = b'%s.err' % test['path']
+                if self.options.outputdir:
+                    errpath = os.path.join(self.options.outputdir, errpath)
+
+                if os.path.exists(errpath):
+                    retest_args.append(test)
+            tests = retest_args
         return tests
 
     def _runtests(self, testdescs):
@@ -3298,7 +3305,6 b' class TestRunner(object):'
                 jobs=jobs,
                 whitelist=self.options.whitelisted,
                 blacklist=self.options.blacklist,
-                retest=self.options.retest,
                 keywords=kws,
                 loop=self.options.loop,
                 runs_per_test=self.options.runs_per_test,

tests/test-run-tests.t

@@ -497,7 +497,7 b' test for --retest'
 ====================
 
   $ rt --retest
-  running 2 tests using 1 parallel processes 
+  running 1 tests using 1 parallel processes 
   
   --- $TESTTMP/test-failure.t
   +++ $TESTTMP/test-failure.t.err
@@ -512,7 +512,7 b' test for --retest'
   ERROR: test-failure.t output changed
   !
   Failed test-failure.t: output changed
-  # Ran 2 tests, 1 skipped, 1 failed.
+  # Ran 1 tests, 0 skipped, 1 failed.
   python hash seed: * (glob)
   [1]
 
@@ -521,7 +521,7 b' test for --retest'
   $ mkdir output
   $ mv test-failure.t.err output
   $ rt --retest --outputdir output
-  running 2 tests using 1 parallel processes 
+  running 1 tests using 1 parallel processes 
   
   --- $TESTTMP/test-failure.t
   +++ $TESTTMP/output/test-failure.t.err
@@ -536,7 +536,7 b' test for --retest'
   ERROR: test-failure.t output changed
   !
   Failed test-failure.t: output changed
-  # Ran 2 tests, 1 skipped, 1 failed.
+  # Ran 1 tests, 0 skipped, 1 failed.
   python hash seed: * (glob)
   [1]
 
@@ -975,7 +975,7 b' When using multiple dimensions of "#test'
   [1]
 
   $ rt --retest
-  running 5 tests using 1 parallel processes 
+  running 1 tests using 1 parallel processes 
   
   --- $TESTTMP/test-cases.t
   +++ $TESTTMP/test-cases.t#b#c.err
@@ -990,7 +990,7 b' When using multiple dimensions of "#test'
   ERROR: test-cases.t#b#c output changed
   !
   Failed test-cases.t#b#c: output changed
-  # Ran 5 tests, 4 skipped, 1 failed.
+  # Ran 1 tests, 0 skipped, 1 failed.
   python hash seed: * (glob)
   [1]
   $ rm test-cases.t#b#c.err