Added test: External link to Markdown file

Author: Laurent Seiler

tests/sphinx_generic/index.md

@@ -17,6 +17,8 @@ This is a [pending ref](index)
 
 [example]: http://example.com/foobar "Example"
 
+External link to Markdown file: [Readme](https://github.com/readthedocs/recommonmark/blob/master/README.md).
+
 Foo
 
 ----

tests/test_sphinx.py

@@ -125,6 +125,12 @@ def test_links(self):
              '</a>'),
             output
         )
+        self.assertIn(
+            ('External link to Markdown file: '
+             '<a class="reference external" '
+             'href="https://github.com/readthedocs/recommonmark/blob/master/README.md">Readme</a>.'),
+            output
+        )
 
     def test_image(self):
         output = self.read_file('index.html')