Change the way unittest.TestSuite use their tests to always access them...

Change the way unittest.TestSuite use their tests to always access them through iteration. Non behavior changing, this allows you to create custom subclasses that override __iter__.

Issue #5693

Lib/unittest.py

@@ -998,7 +998,7 @@ class TestSuite(object):
         self.addTests(tests)
 
     def __repr__(self):
-        return "<%s tests=%s>" % (_strclass(self.__class__), self._tests)
+        return "<%s tests=%s>" % (_strclass(self.__class__), list(self))
 
     def __eq__(self, other):
         if not isinstance(other, self.__class__):
@@ -1016,7 +1016,7 @@ class TestSuite(object):
 
     def countTestCases(self):
         cases = 0
-        for test in self._tests:
+        for test in self:
             cases += test.countTestCases()
         return cases
 
@@ -1036,7 +1036,7 @@ class TestSuite(object):
             self.addTest(test)
 
     def run(self, result):
-        for test in self._tests:
+        for test in self:
             if result.shouldStop:
                 break
             test(result)
@@ -1047,7 +1047,7 @@ class TestSuite(object):
 
     def debug(self):
         """Run the tests without collecting errors in a TestResult"""
-        for test in self._tests:
+        for test in self:
             test.debug()