Merge pull request #170 from scipy/may_vary_at_source

ENH: allow `# may vary` at both source and `want`

Author: ev-br

README.md

@@ -48,8 +48,8 @@ Its main features are
   >>> np.random.randint(100)
   42     # may vary
   ```
-Note that the markers (by default, `"# may vary"` and `"# random"`) are applied
-to an example's output, not its source.
+Note that the markers (by default, `"# may vary"` and `"# random"`) can be applied
+to either an example's output, or its source.
 
 Also note a difference with respect to the standard `# doctest: +SKIP`: the latter
 skips the example entirely, while these additional markers only skip checking

scipy_doctest/impl.py

@@ -514,6 +514,7 @@ def get_examples(self, string, name='<string>'):
         """
         stopwords = self.config.stopwords
         pseudocode = self.config.pseudocode
+        rndm_markers = self.config.rndm_markers
 
         SKIP = doctest.OPTIONFLAGS_BY_NAME['SKIP']
         keep_skipping_this_block = False
@@ -537,6 +538,11 @@ def get_examples(self, string, name='<string>'):
                 # NB: Could have just skipped it via `continue`.
                 example.options[SKIP] = True
 
+            if any(word in example.source for word in rndm_markers):
+                # Found a `# may vary`. Do not check the output (but do check
+                # that the source is valid python).
+                example.want += "  # _ignore\n"
+
             if any(word in example.source for word in stopwords):
                 # Found a stopword. Do not check the output (but do check
                 # that the source is valid python).

scipy_doctest/tests/test_skipmarkers.py

@@ -161,8 +161,25 @@ def test_may_vary_source(self):
                                   filename='none', lineno=0)
 
         runner = DebugDTRunner()
-        with pytest.raises(doctest.DocTestFailure):
+        runner.run(test)
+
+        # one example tried, of which zero failed
+        assert runner.get_history() == {'may_vary_source': (0, 1)}
+
+    def test_may_vary_syntax_error(self):
+        # `# may vary` markers do not mask syntax errors, unlike `# doctest: +SKIP`
+        string = ">>> 1 += 2    # may vary\n"
+        string += "42\n"
+
+        parser = DTParser()
+        test = parser.get_doctest(string, globs={},
+                                  name='may_vary_err',
+                                  filename='none', lineno=0)
+
+        runner = DebugDTRunner()
+        with pytest.raises(Exception) as exc_info:
             runner.run(test)
+        assert exc_info.type == doctest.UnexpectedException
 
 
 string='''\