1 files changed, 50 insertions, 0 deletions
diff --git a/pylint/testutils/checker_test_case.py b/pylint/testutils/checker_test_case.py
new file mode 100644
index 000000000..9b8281513
--- /dev/null
+++ b/pylint/testutils/checker_test_case.py
@@ -0,0 +1,50 @@
+# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+# For details: https://github.com/PyCQA/pylint/blob/master/COPYING
+
+import contextlib
+
+from pylint.testutils.global_test_linter import linter
+from pylint.testutils.unittest_linter import UnittestLinter
+from pylint.utils import ASTWalker
+
+
+class CheckerTestCase:
+    """A base testcase class for unit testing individual checker classes."""
+
+    CHECKER_CLASS = None
+    CONFIG = {}
+
+    def setup_method(self):
+        self.linter = UnittestLinter()
+        self.checker = self.CHECKER_CLASS(self.linter)  # pylint: disable=not-callable
+        for key, value in self.CONFIG.items():
+            setattr(self.checker.config, key, value)
+        self.checker.open()
+
+    @contextlib.contextmanager
+    def assertNoMessages(self):
+        """Assert that no messages are added by the given method."""
+        with self.assertAddsMessages():
+            yield
+
+    @contextlib.contextmanager
+    def assertAddsMessages(self, *messages):
+        """Assert that exactly the given method adds the given messages.
+
+        The list of messages must exactly match *all* the messages added by the
+        method. Additionally, we check to see whether the args in each message can
+        actually be substituted into the message string.
+        """
+        yield
+        got = self.linter.release_messages()
+        msg = "Expected messages did not match actual.\n" "Expected:\n%s\nGot:\n%s" % (
+            "\n".join(repr(m) for m in messages),
+            "\n".join(repr(m) for m in got),
+        )
+        assert list(messages) == got, msg
+
+    def walk(self, node):
+        """recursive walk on the given node"""
+        walker = ASTWalker(linter)
+        walker.add_checker(self.checker)
+        walker.walk(node)