RST306 test case

Author: peterjc

tests/RST306/unknown_target.py

@@ -0,0 +1,19 @@
+"""Print 'Hello world' to the terminal.
+
+Here's where the hyperlink-name_ is used, the target definition
+is next.
+
+.. _hyperlink-name: Here's where the hyperlink target is defined.
+
+So far so good, but what if the definition is not in the same
+docstring fragment - it could be in an included footer?
+
+Here a missing-link_ hyperlink is used, so this docstring in
+isolation should fail validation::
+
+    $ flake8 --select RST  RST306/unknown_target.py 
+    RST306/unknown_target.py:12:1: RST306 Unknown target name: "missing-link".
+
+"""
+
+print("Hello world")