ENH: add ParserKlass key to DTConfig; check xdoctest.DocTestParser

scipy_doctest/impl.py

@@ -103,10 +103,16 @@ class DTConfig:
         instance.
         This class will be instantiated by ``DTRunner``.
         Defaults to `DTChecker`.
+    ParserKlass : object, optional
+        The class for the Parser object. Must mimic the ``DTParser`` API:
+        subclass the `doctest.DocTestParser` and make the constructor signature
+        be ``__init__(self, config=None)``, where ``config`` is a ``DTConfig``
+        instance.
+        This class will be instantiated by ``DTRunner`` via ``DTFinder``.
+        Defaults to ``DTParser``.
 
     """
     def __init__(self, *, # DTChecker configuration
-                          CheckerKlass=None,
                           default_namespace=None,
                           check_namespace=None,
                           rndm_markers=None,
@@ -129,9 +135,11 @@ def __init__(self, *, # DTChecker configuration
                           pytest_extra_ignore=None,
                           pytest_extra_skip=None,
                           pytest_extra_xfail=None,
+                          # plug-and-play configuration
+                          CheckerKlass=None,
+                          ParserKlass=None,
     ):
         ### DTChecker configuration ###
-        self.CheckerKlass = CheckerKlass or DTChecker
 
         # The namespace to run examples in
         self.default_namespace = default_namespace or {}
@@ -217,6 +225,10 @@ def __init__(self, *, # DTChecker configuration
         self.pytest_extra_skip = pytest_extra_skip or {}
         self.pytest_extra_xfail = pytest_extra_xfail or {}
 
+        ### Plug-and-play: Checker/Parser classes
+        self.CheckerKlass = CheckerKlass or DTChecker
+        self.ParserKlass = ParserKlass or DTParser
+
 
 def try_convert_namedtuple(got):
     # suppose that "got" is smth like MoodResult(statistic=10, pvalue=0.1).
@@ -495,7 +507,7 @@ def __init__(self, verbose=None, parser=None, recurse=True,
             config = DTConfig()
         self.config = config
         if parser is None:
-            parser = DTParser(config)
+            parser = config.ParserKlass(config)
         verbose, dtverbose = util._map_verbosity(verbose)
         super().__init__(dtverbose, parser, recurse, exclude_empty)
 

scipy_doctest/tests/test_runner.py

@@ -1,9 +1,13 @@
 import io
-
 import doctest
-
 import pytest
 
+try:
+    import xdoctest
+    HAVE_XDOCTEST = True
+except ModuleNotFoundError:
+    HAVE_XDOCTEST = False
+
 from . import (failure_cases as module,
                finder_cases as finder_module,
                module_cases)
@@ -91,15 +95,71 @@ class VanillaOutputChecker(doctest.OutputChecker):
     def __init__(self, config):
         pass
 
+
 class TestCheckerDropIn:
     """Test DTChecker and vanilla doctest OutputChecker being drop-in replacements.
     """
     def test_vanilla_checker(self):
         config = DTConfig(CheckerKlass=VanillaOutputChecker)
         runner = DebugDTRunner(config=config)
-        tests = DTFinder().find(module_cases.func)
+        tests = DTFinder(config=config).find(module_cases.func)
 
         with pytest.raises(doctest.DocTestFailure):
             for t in tests:
                 runner.run(t)
 
+
+class VanillaParser(doctest.DocTestParser):
+    def __init__(self, config):
+        self.config = config
+        pass
+
+
+class XDParser(doctest.DocTestParser):
+    """ Wrap `xdoctest` parser.
+    """
+    def __init__(self, config):
+        self.config = config
+        self.xd = xdoctest.parser.DoctestParser()
+
+    def parse(self, string, name='<string>'):
+        return self.xd.parse(string)
+
+    def get_examples(self, string, name='<string>'):
+        """
+        Similar to doctest.DocTestParser.get_examples, only
+        account for the fact that individual examples
+        are instances of DoctestPart not doctest.Example
+        """
+        return [x for x in self.parse(string, name)
+                if isinstance(x, xdoctest.doctest_part.DoctestPart)]
+
+
+class TestParserDropIn:
+    """ Test an alternative DoctestParser
+    """
+    def test_vanilla_parser(self):
+        config = DTConfig(ParserKlass=VanillaParser)
+        runner = DebugDTRunner(config=config)
+        tests = DTFinder(config=config).find(module_cases.func3)
+
+        assert len(tests) == 1
+        assert len(tests[0].examples) == 3
+
+    @pytest.mark.skipif(not HAVE_XDOCTEST, reason="needs xdoctest")
+    def test_xdoctest_parser(self):
+        # Note that the # of examples differ from DTParser:
+        # - xdoctest groups doctest lines with no 'want' output into a single
+        #   example.
+        # - "examples" here are DoctestPart instances, which _almost_ quack
+        #    like `doctest.Example` but not completely.
+        config = DTConfig(ParserKlass=XDParser)
+        runner = DebugDTRunner(config=config)
+        tests = DTFinder(config=config).find(module_cases.func3)
+
+        assert len(tests) == 1
+        assert len(tests[0].examples) == 2
+        assert (tests[0].examples[0].source ==
+                'import numpy as np\na = np.array([1, 2, 3, 4]) / 3'
+        )
+        assert tests[0].examples[1].source == 'print(a)'