Merge pull request #6071 from blueyed/tests-doctest-mock

Tests: approx: mock doctest runner's pdb usage

testing/python/approx.py

@@ -1,4 +1,3 @@
-import doctest
 import operator
 from decimal import Decimal
 from fractions import Fraction
@@ -11,10 +10,26 @@ from pytest import approx
 inf, nan = float("inf"), float("nan")
 
 
-class MyDocTestRunner(doctest.DocTestRunner):
+@pytest.fixture
-    def __init__(self):
+def mocked_doctest_runner(monkeypatch):
-        doctest.DocTestRunner.__init__(self)
+    import doctest
 
+    class MockedPdb:
+        def __init__(self, out):
+            pass
+
+        def set_trace(self):
+            raise NotImplementedError("not used")
+
+        def reset(self):
+            pass
+
+        def set_continue(self):
+            pass
+
+    monkeypatch.setattr("doctest._OutputRedirectingPdb", MockedPdb)
+
+    class MyDocTestRunner(doctest.DocTestRunner):
         def report_failure(self, out, test, example, got):
             raise AssertionError(
                 "'{}' evaluates to '{}', not '{}'".format(
@@ -22,6 +37,8 @@ class MyDocTestRunner(doctest.DocTestRunner):
                 )
             )
 
+    return MyDocTestRunner()
+
 
 class TestApprox:
     def test_repr_string(self):
@@ -411,13 +428,14 @@ class TestApprox:
         assert a12 != approx(a21)
         assert a21 != approx(a12)
 
-    def test_doctests(self):
+    def test_doctests(self, mocked_doctest_runner):
+        import doctest
+
         parser = doctest.DocTestParser()
         test = parser.get_doctest(
             approx.__doc__, {"approx": approx}, approx.__name__, None, None
         )
-        runner = MyDocTestRunner()
+        mocked_doctest_runner.run(test)
-        runner.run(test)
 
     def test_unicode_plus_minus(self, testdir):
         """