refactor: remove unittest.assertCountEqual

Another step toward removing unittest.TestCase.

11 files changed, 56 insertions, 62 deletions

diff --git a/coverage/backunittest.py b/coverage/backunittest.py
deleted file mode 100644
index 8b66c0f1..00000000
--- a/coverage/backunittest.py
+++ /dev/null
@@ -1,25 +0,0 @@
-# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
-# For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt
-
-"""Implementations of unittest features from the future."""
-
-import unittest
-
-
-def unittest_has(method):
-    """Does `unittest.TestCase` have `method` defined?"""
-    return hasattr(unittest.TestCase, method)
-
-
-class TestCase(unittest.TestCase):
-    """Just like unittest.TestCase, but with assert methods added.
-
-    Designed to be compatible with 3.1 unittest.  Methods are only defined if
-    `unittest` doesn't have them.
-
-    """
-    # pylint: disable=signature-differs
-
-    if not unittest_has('assertCountEqual'):
-        def assertCountEqual(self, *args, **kwargs):
-            return self.assertItemsEqual(*args, **kwargs)
diff --git a/tests/conftest.py b/tests/conftest.py
index c2e0a893..0ce494c8 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -19,6 +19,7 @@ from coverage import env
 # Pytest will rewrite assertions in test modules, but not elsewhere.
 # This tells pytest to also rewrite assertions in coveragetest.py.
 pytest.register_assert_rewrite("tests.coveragetest")
+pytest.register_assert_rewrite("tests.helpers")
 
 # Pytest can take additional options:
 # $set_env.py: PYTEST_ADDOPTS - Extra arguments to pytest.
diff --git a/tests/coveragetest.py b/tests/coveragetest.py
index 71f4e2c8..69dbb7cf 100644
--- a/tests/coveragetest.py
+++ b/tests/coveragetest.py
@@ -13,17 +13,17 @@ import random
 import re
 import shlex
 import sys
+import unittest
 
 import pytest
 from unittest_mixins import EnvironmentAwareMixin, TempDirMixin
 
 import coverage
 from coverage import env
-from coverage.backunittest import TestCase
 from coverage.backward import StringIO, import_local_file, string_class, shlex_quote
 from coverage.cmdline import CoverageScript
 
-from tests.helpers import arcs_to_arcz_repr, arcz_to_arcs
+from tests.helpers import arcs_to_arcz_repr, arcz_to_arcs, assert_count_equal
 from tests.helpers import run_command, SuperModuleCleaner
 from tests.mixins import StdStreamCapturingMixin, StopEverythingMixin
 
@@ -40,7 +40,7 @@ class CoverageTest(
     StdStreamCapturingMixin,
     TempDirMixin,
     StopEverythingMixin,
-    TestCase,
+    unittest.TestCase,
 ):
     """A base class for coverage.py test cases."""
 
@@ -283,7 +283,7 @@ class CoverageTest(
         """Assert that `flist1` and `flist2` are the same set of file names."""
         flist1_nice = [self.nice_file(f) for f in flist1]
         flist2_nice = [self.nice_file(f) for f in flist2]
-        self.assertCountEqual(flist1_nice, flist2_nice)
+        assert_count_equal(flist1_nice, flist2_nice)
 
     def assert_exists(self, fname):
         """Assert that `fname` is a file that exists."""
diff --git a/tests/helpers.py b/tests/helpers.py
index 0621d7a9..1348aad6 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -3,6 +3,7 @@
 
 """Helpers for coverage.py tests."""
 
+import collections
 import glob
 import os
 import re
@@ -222,3 +223,13 @@ def without_module(using_module, missing_module_name):
 
     """
     return mock.patch.object(using_module, missing_module_name, None)
+
+
+def assert_count_equal(a, b):
+    """
+    A pytest-friendly implementation of assertCountEqual.
+
+    Assert that `a` and `b` have the same elements, but maybe in different order.
+    This only works for hashable elements.
+    """
+    assert collections.Counter(list(a)) == collections.Counter(list(b))
diff --git a/tests/mixins.py b/tests/mixins.py
index ab0623c0..9d096d4d 100644
--- a/tests/mixins.py
+++ b/tests/mixins.py
@@ -9,10 +9,10 @@ Some of these are transitional while working toward pure-pytest style.
 
 import functools
 import types
+import unittest
 
 import pytest
 
-from coverage.backunittest import unittest
 from coverage.misc import StopEverything
 
 
diff --git a/tests/test_api.py b/tests/test_api.py
index ea625ff1..0c1c9035 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -23,6 +23,7 @@ from coverage.files import abs_file, relative_filename
 from coverage.misc import CoverageException
 
 from tests.coveragetest import CoverageTest, StopEverythingMixin, TESTS_DIR, UsingModulesMixin
+from tests.helpers import assert_count_equal
 
 
 class ApiTest(CoverageTest):
@@ -43,7 +44,7 @@ class ApiTest(CoverageTest):
         """Assert that the files here are `files`, ignoring the usual junk."""
         here = os.listdir(".")
         here = self.clean_files(here, ["*.pyc", "__pycache__", "*$py.class"])
-        self.assertCountEqual(here, files)
+        assert_count_equal(here, files)
 
     def test_unexecuted_file(self):
         cov = coverage.Coverage()
diff --git a/tests/test_arcs.py b/tests/test_arcs.py
index 66777751..c6cf7952 100644
--- a/tests/test_arcs.py
+++ b/tests/test_arcs.py
@@ -6,6 +6,7 @@
 import pytest
 
 from tests.coveragetest import CoverageTest
+from tests.helpers import assert_count_equal
 
 import coverage
 from coverage import env
@@ -1732,4 +1733,4 @@ class LineDataTest(CoverageTest):
 
         data = cov.get_data()
         fun1_lines = data.lines(abs_file("fun1.py"))
-        self.assertCountEqual(fun1_lines, [1, 2, 5])
+        assert_count_equal(fun1_lines, [1, 2, 5])
diff --git a/tests/test_backward.py b/tests/test_backward.py
index 767a7ac8..d750022b 100644
--- a/tests/test_backward.py
+++ b/tests/test_backward.py
@@ -3,16 +3,19 @@
 
 """Tests that our version shims in backward.py are working."""
 
-from coverage.backunittest import TestCase
+import unittest
+
 from coverage.backward import iitems, binary_bytes, bytes_to_ints
 
-class BackwardTest(TestCase):
+from tests.helpers import assert_count_equal
+
+class BackwardTest(unittest.TestCase):
     """Tests of things from backward.py."""
 
     def test_iitems(self):
         d = {'a': 1, 'b': 2, 'c': 3}
         items = [('a', 1), ('b', 2), ('c', 3)]
-        self.assertCountEqual(list(iitems(d)), items)
+        assert_count_equal(list(iitems(d)), items)
 
     def test_binary_bytes(self):
         byte_values = [0, 255, 17, 23, 42, 57]
diff --git a/tests/test_context.py b/tests/test_context.py
index 418849d5..20b7a290 100644
--- a/tests/test_context.py
+++ b/tests/test_context.py
@@ -12,6 +12,7 @@ from coverage.context import qualname_from_frame
 from coverage.data import CoverageData
 
 from tests.coveragetest import CoverageTest
+from tests.helpers import assert_count_equal
 
 
 class StaticContextTest(CoverageTest):
@@ -22,14 +23,14 @@ class StaticContextTest(CoverageTest):
         cov = coverage.Coverage()
         self.start_import_stop(cov, "main")
         data = cov.get_data()
-        self.assertCountEqual(data.measured_contexts(), [""])
+        assert_count_equal(data.measured_contexts(), [""])
 
     def test_static_context(self):
         self.make_file("main.py", "a = 1")
         cov = coverage.Coverage(context="gooey")
         self.start_import_stop(cov, "main")
         data = cov.get_data()
-        self.assertCountEqual(data.measured_contexts(), ["gooey"])
+        assert_count_equal(data.measured_contexts(), ["gooey"])
 
     SOURCE = """\
         a = 1
@@ -67,7 +68,7 @@ class StaticContextTest(CoverageTest):
             assert combined.measured_contexts() == {'red', 'blue'}
 
             full_names = {os.path.basename(f): f for f in combined.measured_files()}
-            self.assertCountEqual(full_names, ['red.py', 'blue.py'])
+            assert_count_equal(full_names, ['red.py', 'blue.py'])
 
             fred = full_names['red.py']
             fblue = full_names['blue.py']
@@ -92,7 +93,7 @@ class StaticContextTest(CoverageTest):
             assert combined.measured_contexts() == {'red', 'blue'}
 
             full_names = {os.path.basename(f): f for f in combined.measured_files()}
-            self.assertCountEqual(full_names, ['red.py', 'blue.py'])
+            assert_count_equal(full_names, ['red.py', 'blue.py'])
 
             fred = full_names['red.py']
             fblue = full_names['blue.py']
@@ -157,13 +158,14 @@ class DynamicContextTest(CoverageTest):
 
         full_names = {os.path.basename(f): f for f in data.measured_files()}
         fname = full_names["two_tests.py"]
-        self.assertCountEqual(
+        assert_count_equal(
             data.measured_contexts(),
-            ["", "two_tests.test_one", "two_tests.test_two"])
+            ["", "two_tests.test_one", "two_tests.test_two"]
+        )
 
         def assert_context_lines(context, lines):
             data.set_query_context(context)
-            self.assertCountEqual(lines, data.lines(fname))
+            assert_count_equal(lines, data.lines(fname))
 
         assert_context_lines("", self.OUTER_LINES)
         assert_context_lines("two_tests.test_one", self.TEST_ONE_LINES)
@@ -178,13 +180,14 @@ class DynamicContextTest(CoverageTest):
 
         full_names = {os.path.basename(f): f for f in data.measured_files()}
         fname = full_names["two_tests.py"]
-        self.assertCountEqual(
+        assert_count_equal(
             data.measured_contexts(),
-            ["stat", "stat|two_tests.test_one", "stat|two_tests.test_two"])
+            ["stat", "stat|two_tests.test_one", "stat|two_tests.test_two"]
+        )
 
         def assert_context_lines(context, lines):
             data.set_query_context(context)
-            self.assertCountEqual(lines, data.lines(fname))
+            assert_count_equal(lines, data.lines(fname))
 
         assert_context_lines("stat", self.OUTER_LINES)
         assert_context_lines("stat|two_tests.test_one", self.TEST_ONE_LINES)
diff --git a/tests/test_data.py b/tests/test_data.py
index 789bdd5a..fe37bd9e 100644
--- a/tests/test_data.py
+++ b/tests/test_data.py
@@ -20,6 +20,7 @@ from coverage.files import PathAliases, canonical_filename
 from coverage.misc import CoverageException
 
 from tests.coveragetest import CoverageTest
+from tests.helpers import assert_count_equal
 
 
 LINES_1 = {
@@ -82,23 +83,23 @@ class DataTestHelpers(CoverageTest):
 
     def assert_measured_files(self, covdata, measured):
         """Check that `covdata`'s measured files are `measured`."""
-        self.assertCountEqual(covdata.measured_files(), measured)
+        assert_count_equal(covdata.measured_files(), measured)
 
     def assert_lines1_data(self, covdata):
         """Check that `covdata` has the data from LINES1."""
         self.assert_line_counts(covdata, SUMMARY_1)
         self.assert_measured_files(covdata, MEASURED_FILES_1)
-        self.assertCountEqual(covdata.lines("a.py"), A_PY_LINES_1)
+        assert_count_equal(covdata.lines("a.py"), A_PY_LINES_1)
         assert not covdata.has_arcs()
 
     def assert_arcs3_data(self, covdata):
         """Check that `covdata` has the data from ARCS3."""
         self.assert_line_counts(covdata, SUMMARY_3)
         self.assert_measured_files(covdata, MEASURED_FILES_3)
-        self.assertCountEqual(covdata.lines("x.py"), X_PY_LINES_3)
-        self.assertCountEqual(covdata.arcs("x.py"), X_PY_ARCS_3)
-        self.assertCountEqual(covdata.lines("y.py"), Y_PY_LINES_3)
-        self.assertCountEqual(covdata.arcs("y.py"), Y_PY_ARCS_3)
+        assert_count_equal(covdata.lines("x.py"), X_PY_LINES_3)
+        assert_count_equal(covdata.arcs("x.py"), X_PY_ARCS_3)
+        assert_count_equal(covdata.lines("y.py"), Y_PY_LINES_3)
+        assert_count_equal(covdata.arcs("y.py"), Y_PY_ARCS_3)
         assert covdata.has_arcs()
 
 
diff --git a/tests/test_testing.py b/tests/test_testing.py
index b6ffe1a0..67ec8dff 100644
--- a/tests/test_testing.py
+++ b/tests/test_testing.py
@@ -8,18 +8,18 @@ import datetime
 import os
 import re
 import sys
+import unittest
 
 import pytest
 
 import coverage
 from coverage import tomlconfig
-from coverage.backunittest import TestCase, unittest
 from coverage.files import actual_path
 from coverage.misc import StopEverything
 
 from tests.coveragetest import CoverageTest
 from tests.helpers import (
-    arcs_to_arcz_repr, arcz_to_arcs,
+    arcs_to_arcz_repr, arcz_to_arcs, assert_count_equal,
     CheckUniqueFilenames, re_lines, re_line, without_module,
 )
 from tests.mixins import convert_skip_exceptions
@@ -31,15 +31,13 @@ def test_xdist_sys_path_nuttiness_is_fixed():
     assert os.environ.get('PYTHONPATH') is None
 
 
-class TestingTest(TestCase):
-    """Tests of helper methods on `backunittest.TestCase`."""
-
-    def test_assert_count_equal(self):
-        self.assertCountEqual(set(), set())
-        with pytest.raises(AssertionError):
-            self.assertCountEqual({1,2,3}, set())
-        with pytest.raises(AssertionError):
-            self.assertCountEqual({1,2,3}, {4,5,6})
+def test_assert_count_equal():
+    assert_count_equal(set(), set())
+    assert_count_equal({"a": 1, "b": 2}, ["b", "a"])
+    with pytest.raises(AssertionError):
+        assert_count_equal({1,2,3}, set())
+    with pytest.raises(AssertionError):
+        assert_count_equal({1,2,3}, {4,5,6})
 
 
 class CoverageTestTest(CoverageTest):