Add a test to check that suffixes aren't applied

IPython/nbconvert/tests/test_nbconvertapp.py

@@ -210,3 +210,25 b' class TestNbConvertApp(TestsBase):'
             self.create_empty_notebook(u'empty.ipynb')
             self.call('nbconvert empty --to html --NbConvertApp.writer_class=\'hello.HelloWriter\'')
             assert os.path.isfile(u'hello.txt')
+
+    def test_output_suffix(self):
+        """
+        Verify that the output suffix is applied
+        """
+        with self.create_temp_cwd():
+            self.create_empty_notebook('empty.ipynb')
+            self.call('nbconvert empty.ipynb --to notebook')
+            assert os.path.isfile('empty.nbconvert.ipynb')
+
+    def test_no_output_suffix(self):
+        """
+        Verify that the output suffix is not applied
+        """
+        with self.create_temp_cwd():
+            self.create_empty_notebook('empty.ipynb')
+            os.mkdir('output')
+            self.call(
+                'nbconvert empty.ipynb --to notebook '
+                '--FilesWriter.build_directory=output '
+                '--no-output-suffix')
+            assert os.path.isfile('output/empty.ipynb')