Use RegexEq in configtypes tests

This prevents the tests from failing if the regex cache overflows,
since re.compile objects compare by identitiy instead of patterns.

tests/unit/config/test_configtypes.py

@@ -69,6 +69,34 @@ class NetworkProxy(QNetworkProxy):
                               password=self.password())
 
 
+class RegexEq:
+
+    """A class to compare regex objects."""
+
+    def __init__(self, pattern, flags=0):
+        # We compile the regex because re.compile also adds flags defined in
+        # the pattern and implicit flags to it's .flags.
+        # See https://docs.python.org/3/library/re.html#re.regex.flags
+        compiled = re.compile(pattern, flags)
+        self.pattern = compiled.pattern
+        self.flags = compiled.flags
+        self._user_flags = flags
+
+    def __eq__(self, other):
+        try:
+            # Works for RegexEq objects and re.compile objects
+            return (self.pattern, self.flags) == (other.pattern, other.flags)
+        except AttributeError:
+            return NotImplemented
+
+    def __repr__(self):
+        if self._user_flags:
+            return "RegexEq({!r}, flags={})".format(self.pattern,
+                                                    self._user_flags)
+        else:
+            return "RegexEq({!r})".format(self.pattern)
+
+
 @pytest.fixture
 def os_mock(mocker):
     """Fixture that mocks and returns os from the configtypes module."""
@@ -1037,7 +1065,7 @@ class TestRegex:
             klass().validate(val)
 
     @pytest.mark.parametrize('val, expected', [
-        (r'foobar', re.compile(r'foobar')),
+        (r'foobar', RegexEq(r'foobar')),
         ('', None),
     ])
     def test_transform_empty(self, klass, val, expected):
@@ -1070,10 +1098,10 @@ class TestRegexList:
             klass().validate(val)
 
     @pytest.mark.parametrize('val, expected', [
-        ('foo', [re.compile('foo')]),
-        ('foo,bar,baz', [re.compile('foo'), re.compile('bar'),
-                         re.compile('baz')]),
-        ('foo,,bar', [re.compile('foo'), None, re.compile('bar')]),
+        ('foo', [RegexEq('foo')]),
+        ('foo,bar,baz', [RegexEq('foo'), RegexEq('bar'),
+                         RegexEq('baz')]),
+        ('foo,,bar', [RegexEq('foo'), None, RegexEq('bar')]),
         ('', None),
     ])
     def test_transform(self, klass, val, expected):