testsuite: test for exceptions raised without messages

2 files changed, 35 insertions, 0 deletions

diff --git a/testsuite/ext/__init__.py b/testsuite/ext/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/testsuite/ext/__init__.py
diff --git a/testsuite/ext/exception_messages.py b/testsuite/ext/exception_messages.py
new file mode 100644
index 000000000..877ba42a1
--- /dev/null
+++ b/testsuite/ext/exception_messages.py
@@ -0,0 +1,35 @@
+from logilab import astng
+from pylint.interfaces import IASTNGChecker
+from pylint.checkers import BaseChecker
+from pylint.checkers.utils import safe_infer
+
+
+class ExceptionMessageChecker(BaseChecker):
+    __implements__ = IASTNGChecker
+
+    name = 'Exception Messages'
+    msgs = \
+        {'R9901': ('Exception raised without arguments',
+                   'Used when an exception is raised without any arguments')}
+    options = (
+        ('exceptions-without-args',
+         dict(default=('NotImplementedError',),
+              type='csv',
+              metavar='<exception names>',
+              help='List of exception names that may be raised without arguments')),)
+    # this is important so that your checker is executed before others
+    priority = -1
+
+    def visit_raise(self, node):
+        if node.exc is None:
+            return
+        if isinstance(node.exc, astng.Name):
+            raised = safe_infer(node.exc)
+            if (isinstance(raised, astng.Class) and
+                raised.name not in self.config.exceptions_without_args):
+                self.add_message('R9901', node=node.exc)
+
+
+def register(linter):
+    """required method to auto register this checker"""
+    linter.register_checker(ExceptionMessageChecker(linter))