Added pyversion option for doctest (issue 3303)

Code, tests and documentation.

doc/ext/doctest.rst

@@ -63,7 +63,7 @@ a comma-separated list of group names.
    default set of flags is specified by the :confval:`doctest_default_flags`
    configuration variable.
 
-   This directive supports two options:
+   This directive supports three options:
 
    * ``hide``, a flag option, hides the doctest block in other builders.  By
      default it is shown as a highlighted doctest block.
@@ -73,6 +73,17 @@ a comma-separated list of group names.
      explicit flags per example, with doctest comments, but they will show up in
      other builders too.)
 
+   * ``pyversion``, a string option, can be used to specify the required Python
+     version for the example to be tested. For instance, in the following case
+     the example will be tested only for Python versions greather than 3.3::
+
+         .. doctest::
+            :pyversion: > 3.3
+             
+     The supported operands are ``<``, ``<=``, ``==``, ``>=``, and ``>``.
+     
+     .. versionadded:: 1.5
+
    Note that like with standard doctests, you have to use ``<BLANKLINE>`` to
    signal a blank line in the expected output.  The ``<BLANKLINE>`` is removed
    when building presentation output (HTML, LaTeX etc.).

sphinx/ext/doctest.py

@@ -133,7 +133,7 @@ class TestDirective(Directive):
         This function is meant to be used to evaluate the doctest :pyversion:
         option. For instance, if the doctest directive provides the option
         :pyversion: >= 3.3, then we have to check if the running Python version
-        is greather or equal to 3.3. In that case, operand will be the string
+        is greather or equal than 3.3. In that case, operand will be the string
         '>=' and version the string '3.3'. proper_pyversion() will return True
         if the running Python version is >= 3.3, False otherwise.
         """

tests/test_ext_doctest.py

@@ -28,9 +28,7 @@ def test_build(app, status, warning):
 
 
 def test_pyversion(monkeypatch):
-    def python_version():
-        return '3.3'
-    monkeypatch.setattr(platform, 'python_version', python_version)
+    monkeypatch.setattr(platform, 'python_version', lambda: '3.3')
     td = _TestDirective(*([None] * 9))
     assert td.proper_pyversion('<', '3.4') is True
     assert td.proper_pyversion('<', '3.2') is False