bitbake: COW: migrate test suite into tests/cow

Convert the test suite that was in COW.py into something that
will actually run as part of bitbake-selftest. This is in
preparation for some cleanups I plan in COW.py.

(Bitbake rev: a73d45cb6010e14bf93fec857303bc7ff321066f)

Signed-off-by: Chris Laplante <chris.laplante@agilent.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 206 insertions, 134 deletions

diff --git a/bitbake/lib/bb/COW.py b/bitbake/lib/bb/COW.py
index 3785a8b03e..23c22b65ef 100644
--- a/bitbake/lib/bb/COW.py
+++ b/bitbake/lib/bb/COW.py
@@ -193,125 +193,3 @@ class COWDictBase(metaclass=COWDictMeta):
 
 class COWSetBase(metaclass=COWSetMeta):
     __count__ = 0
-
-if __name__ == "__main__":
-    import sys
-    COWDictBase.__warn__ = sys.stderr
-    a = COWDictBase()
-    print("a", a)
-
-    a['a'] = 'a'
-    a['b'] = 'b'
-    a['dict'] = {}
-
-    b = a.copy()
-    print("b", b)
-    b['c'] = 'b'
-
-    print()
-
-    print("a", a)
-    for x in a.iteritems():
-        print(x)
-    print("--")
-    print("b", b)
-    for x in b.iteritems():
-        print(x)
-    print()
-
-    b['dict']['a'] = 'b'
-    b['a'] = 'c'
-
-    print("a", a)
-    for x in a.iteritems():
-        print(x)
-    print("--")
-    print("b", b)
-    for x in b.iteritems():
-        print(x)
-    print()
-
-    try:
-        b['dict2']
-    except KeyError as e:
-        print("Okay!")
-
-    a['set'] = COWSetBase()
-    a['set'].add("o1")
-    a['set'].add("o1")
-    a['set'].add("o2")
-
-    print("a", a)
-    for x in a['set'].itervalues():
-        print(x)
-    print("--")
-    print("b", b)
-    for x in b['set'].itervalues():
-        print(x)
-    print()
-
-    b['set'].add('o3')
-
-    print("a", a)
-    for x in a['set'].itervalues():
-        print(x)
-    print("--")
-    print("b", b)
-    for x in b['set'].itervalues():
-        print(x)
-    print()
-
-    a['set2'] = set()
-    a['set2'].add("o1")
-    a['set2'].add("o1")
-    a['set2'].add("o2")
-
-    print("a", a)
-    for x in a.iteritems():
-        print(x)
-    print("--")
-    print("b", b)
-    for x in b.iteritems(readonly=True):
-        print(x)
-    print()
-
-    del b['b']
-    try:
-        print(b['b'])
-    except KeyError:
-        print("Yay! deleted key raises error")
-
-    if 'b' in b:
-        print("Boo!")
-    else:
-        print("Yay - has_key with delete works!")
-
-    print("a", a)
-    for x in a.iteritems():
-        print(x)
-    print("--")
-    print("b", b)
-    for x in b.iteritems(readonly=True):
-        print(x)
-    print()
-
-    b.__revertitem__('b')
-
-    print("a", a)
-    for x in a.iteritems():
-        print(x)
-    print("--")
-    print("b", b)
-    for x in b.iteritems(readonly=True):
-        print(x)
-    print()
-
-    b.__revertitem__('dict')
-    print("a", a)
-    for x in a.iteritems():
-        print(x)
-    print("--")
-    print("b", b)
-    for x in b.iteritems(readonly=True):
-        print(x)
-    print()
diff --git a/bitbake/lib/bb/tests/cow.py b/bitbake/lib/bb/tests/cow.py
index bf6e79fcee..75142649c4 100644
--- a/bitbake/lib/bb/tests/cow.py
+++ b/bitbake/lib/bb/tests/cow.py
@@ -4,9 +4,17 @@
 # SPDX-License-Identifier: GPL-2.0-only
 #
 # Copyright 2006 Holger Freyther <freyther@handhelds.org>
+# Copyright (C) 2020  Agilent Technologies, Inc.
 #
 
+import io
+import re
+import sys
 import unittest
+import contextlib
+import collections
+
+from bb.COW import COWDictBase, COWSetBase, COWDictMeta, COWSetMeta
 
 
 class COWTestCase(unittest.TestCase):
@@ -14,11 +22,61 @@ class COWTestCase(unittest.TestCase):
     Test case for the COW module from mithro
     """
 
+    def setUp(self):
+        self._track_warnings = False
+        self._warning_file = io.StringIO()
+        self._unhandled_warnings = collections.deque()
+        COWDictBase.__warn__ = self._warning_file
+
+    def tearDown(self):
+        COWDictBase.__warn__ = sys.stderr
+        if self._track_warnings:
+            self._checkAllWarningsRead()
+
+    def trackWarnings(self):
+        self._track_warnings = True
+
+    def _collectWarnings(self):
+        self._warning_file.seek(0)
+        for warning in self._warning_file:
+            self._unhandled_warnings.append(warning.rstrip("\n"))
+        self._warning_file.truncate(0)
+        self._warning_file.seek(0)
+
+    def _checkAllWarningsRead(self):
+        self._collectWarnings()
+        self.assertSequenceEqual(self._unhandled_warnings, [])
+
+    @contextlib.contextmanager
+    def checkReportsWarning(self, expected_warning):
+        self._checkAllWarningsRead()
+        yield
+        self._collectWarnings()
+        warning = self._unhandled_warnings.popleft()
+        self.assertEqual(warning, expected_warning)
+
+    def checkStrOutput(self, obj, expected_levels, expected_keys):
+        if obj.__class__ is COWDictMeta:
+            expected_class_name = "COWDict"
+        elif obj.__class__ is COWSetMeta:
+            expected_class_name = "COWSet"
+        else:
+            self.fail("obj is of unknown type {0}".format(type(obj)))
+        s = str(obj)
+        regex = re.compile(r"<(\w+) Level: (\d+) Current Keys: (\d+)>")
+        match = regex.match(s)
+        self.assertIsNotNone(match, "bad str output: '{0}'".format(s))
+        class_name = match.group(1)
+        self.assertEqual(class_name, expected_class_name)
+        levels = int(match.group(2))
+        self.assertEqual(levels, expected_levels, "wrong # levels in str: '{0}'".format(s))
+        keys = int(match.group(3))
+        self.assertEqual(keys, expected_keys, "wrong # keys in str: '{0}'".format(s))
+
     def testGetSet(self):
         """
         Test and set
         """
-        from bb.COW import COWDictBase
         a = COWDictBase.copy()
 
         self.assertEqual(False, 'a' in a)
@@ -27,16 +85,14 @@ class COWTestCase(unittest.TestCase):
         a['b'] = 'b'
         self.assertEqual(True, 'a' in a)
         self.assertEqual(True, 'b' in a)
-        self.assertEqual('a', a['a'] )
-        self.assertEqual('b', a['b'] )
+        self.assertEqual('a', a['a'])
+        self.assertEqual('b', a['b'])
 
     def testCopyCopy(self):
         """
         Test the copy of copies
         """
 
-        from bb.COW import COWDictBase
-
         # create two COW dict 'instances'
         b = COWDictBase.copy()
         c = COWDictBase.copy()
@@ -94,30 +150,168 @@ class COWTestCase(unittest.TestCase):
         self.assertEqual(False, 'e' in b_2)
 
     def testCow(self):
-        from bb.COW import COWDictBase
+        self.trackWarnings()
+
         c = COWDictBase.copy()
         c['123'] = 1027
         c['other'] = 4711
-        c['d'] = { 'abc' : 10, 'bcd' : 20 }
+        c['d'] = {'abc': 10, 'bcd': 20}
 
         copy = c.copy()
 
         self.assertEqual(1027, c['123'])
         self.assertEqual(4711, c['other'])
-        self.assertEqual({'abc':10, 'bcd':20}, c['d'])
+        self.assertEqual({'abc': 10, 'bcd': 20}, c['d'])
         self.assertEqual(1027, copy['123'])
         self.assertEqual(4711, copy['other'])
-        self.assertEqual({'abc':10, 'bcd':20}, copy['d'])
+        with self.checkReportsWarning("Warning: Doing a copy because d is a mutable type."):
+            self.assertEqual({'abc': 10, 'bcd': 20}, copy['d'])
 
         # cow it now
         copy['123'] = 1028
         copy['other'] = 4712
         copy['d']['abc'] = 20
 
-
         self.assertEqual(1027, c['123'])
         self.assertEqual(4711, c['other'])
-        self.assertEqual({'abc':10, 'bcd':20}, c['d'])
+        self.assertEqual({'abc': 10, 'bcd': 20}, c['d'])
         self.assertEqual(1028, copy['123'])
         self.assertEqual(4712, copy['other'])
-        self.assertEqual({'abc':20, 'bcd':20}, copy['d'])
+        self.assertEqual({'abc': 20, 'bcd': 20}, copy['d'])
+
+    def testOriginalTestSuite(self):
+        # This test suite is a port of the original one from COW.py
+        self.trackWarnings()
+
+        a = COWDictBase.copy()
+        self.checkStrOutput(a, 1, 0)
+
+        a['a'] = 'a'
+        a['b'] = 'b'
+        a['dict'] = {}
+        self.checkStrOutput(a, 1, 4)  # 4th member is dict__mutable__
+
+        b = a.copy()
+        self.checkStrOutput(b, 2, 0)
+        b['c'] = 'b'
+        self.checkStrOutput(b, 2, 1)
+
+        with self.checkReportsWarning("Warning: If you aren't going to change any of the values call with True."):
+            self.assertListEqual(list(a.iteritems()),
+                                 [('a', 'a'),
+                                  ('b', 'b'),
+                                  ('dict', {})
+                                  ])
+
+        with self.checkReportsWarning("Warning: If you aren't going to change any of the values call with True."):
+            b_gen = b.iteritems()
+        self.assertTupleEqual(next(b_gen), ('a', 'a'))
+        self.assertTupleEqual(next(b_gen), ('b', 'b'))
+        self.assertTupleEqual(next(b_gen), ('c', 'b'))
+        with self.checkReportsWarning("Warning: Doing a copy because dict is a mutable type."):
+            self.assertTupleEqual(next(b_gen), ('dict', {}))
+        with self.assertRaises(StopIteration):
+            next(b_gen)
+
+        b['dict']['a'] = 'b'
+        b['a'] = 'c'
+
+        self.checkStrOutput(a, 1, 4)
+        self.checkStrOutput(b, 2, 3)
+
+        with self.checkReportsWarning("Warning: If you aren't going to change any of the values call with True."):
+            self.assertListEqual(list(a.iteritems()),
+                                 [('a', 'a'),
+                                  ('b', 'b'),
+                                  ('dict', {})
+                                  ])
+
+        with self.checkReportsWarning("Warning: If you aren't going to change any of the values call with True."):
+            b_gen = b.iteritems()
+        self.assertTupleEqual(next(b_gen), ('a', 'c'))
+        self.assertTupleEqual(next(b_gen), ('b', 'b'))
+        self.assertTupleEqual(next(b_gen), ('c', 'b'))
+        self.assertTupleEqual(next(b_gen), ('dict', {'a': 'b'}))
+        with self.assertRaises(StopIteration):
+            next(b_gen)
+
+        with self.assertRaises(KeyError):
+            print(b["dict2"])
+
+        a['set'] = COWSetBase()
+        a['set'].add("o1")
+        a['set'].add("o1")
+        a['set'].add("o2")
+        self.assertSetEqual(set(a['set'].itervalues()), {"o1", "o2"})
+        self.assertSetEqual(set(b['set'].itervalues()), {"o1", "o2"})
+
+        b['set'].add('o3')
+        self.assertSetEqual(set(a['set'].itervalues()), {"o1", "o2"})
+        self.assertSetEqual(set(b['set'].itervalues()), {"o1", "o2", "o3"})
+
+        a['set2'] = set()
+        a['set2'].add("o1")
+        a['set2'].add("o1")
+        a['set2'].add("o2")
+
+        # We don't expect 'a' to change anymore
+        def check_a():
+            with self.checkReportsWarning("Warning: If you aren't going to change any of the values call with True."):
+                a_gen = a.iteritems()
+                self.assertTupleEqual(next(a_gen), ('a', 'a'))
+            self.assertTupleEqual(next(a_gen), ('b', 'b'))
+            self.assertTupleEqual(next(a_gen), ('dict', {}))
+            self.assertTupleEqual(next(a_gen), ('set2', {'o1', 'o2'}))
+            a_sub_set = next(a_gen)
+            self.assertEqual(a_sub_set[0], 'set')
+            self.checkStrOutput(a_sub_set[1], 1, 2)
+            self.assertSetEqual(set(a_sub_set[1].itervalues()), {'o1', 'o2'})
+
+        check_a()
+
+        b_gen = b.iteritems(readonly=True)
+        self.assertTupleEqual(next(b_gen), ('a', 'c'))
+        self.assertTupleEqual(next(b_gen), ('b', 'b'))
+        self.assertTupleEqual(next(b_gen), ('c', 'b'))
+        self.assertTupleEqual(next(b_gen), ('dict', {'a': 'b'}))
+        self.assertTupleEqual(next(b_gen), ('set2', {'o1', 'o2'}))
+        b_sub_set = next(b_gen)
+        self.assertEqual(b_sub_set[0], 'set')
+        self.checkStrOutput(b_sub_set[1], 2, 1)
+        self.assertSetEqual(set(b_sub_set[1].itervalues()), {'o1', 'o2', 'o3'})
+
+        del b['b']
+        with self.assertRaises(KeyError):
+            print(b['b'])
+        self.assertFalse('b' in b)
+
+        check_a()
+
+        b.__revertitem__('b')
+        check_a()
+        self.assertEqual(b['b'], 'b')
+        self.assertTrue('b' in b)
+
+        b.__revertitem__('dict')
+        check_a()
+
+        b_gen = b.iteritems(readonly=True)
+        self.assertTupleEqual(next(b_gen), ('a', 'c'))
+        self.assertTupleEqual(next(b_gen), ('b', 'b'))
+        self.assertTupleEqual(next(b_gen), ('c', 'b'))
+        self.assertTupleEqual(next(b_gen), ('dict', {}))
+        self.assertTupleEqual(next(b_gen), ('set2', {'o1', 'o2'}))
+        b_sub_set = next(b_gen)
+        self.assertEqual(b_sub_set[0], 'set')
+        self.checkStrOutput(b_sub_set[1], 2, 1)
+        self.assertSetEqual(set(b_sub_set[1].itervalues()), {'o1', 'o2', 'o3'})
+
+        self.checkStrOutput(a, 1, 6)
+        self.checkStrOutput(b, 2, 3)
+
+    def testSetMethods(self):
+        s = COWSetBase()
+        with self.assertRaises(TypeError):
+            print(s.iteritems())
+        with self.assertRaises(TypeError):
+            print(s.iterkeys())