refactor: our own change_dir context manager

We don't need to use the one from unittest_mixins.

4 files changed, 20 insertions, 4 deletions

diff --git a/tests/helpers.py b/tests/helpers.py
index a96b793e..195fefde 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -4,6 +4,7 @@
 """Helpers for coverage.py tests."""
 
 import collections
+import contextlib
 import glob
 import os
 import re
@@ -207,6 +208,22 @@ def arcs_to_arcz_repr(arcs):
     return "\n".join(repr_list) + "\n"
 
 
+@contextlib.contextmanager
+def change_dir(new_dir):
+    """Change directory, and then change back.
+
+    Use as a context manager, it will return to the original
+    directory at the end of the block.
+
+    """
+    old_dir = os.getcwd()
+    os.chdir(new_dir)
+    try:
+        yield
+    finally:
+        os.chdir(old_dir)
+
+
 def without_module(using_module, missing_module_name):
     """
     Hide a module for testing.
diff --git a/tests/test_api.py b/tests/test_api.py
index 3a5c86ac..93b14c58 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -13,7 +13,6 @@ import sys
 import textwrap
 
 import pytest
-from unittest_mixins import change_dir
 
 import coverage
 from coverage import env
@@ -23,7 +22,7 @@ from coverage.files import abs_file, relative_filename
 from coverage.misc import CoverageException
 
 from tests.coveragetest import CoverageTest, TESTS_DIR, UsingModulesMixin
-from tests.helpers import assert_count_equal
+from tests.helpers import assert_count_equal, change_dir
 
 
 class ApiTest(CoverageTest):
diff --git a/tests/test_html.py b/tests/test_html.py
index 1015b7d6..5b0e0345 100644
--- a/tests/test_html.py
+++ b/tests/test_html.py
@@ -14,7 +14,6 @@ import sys
 
 import mock
 import pytest
-from unittest_mixins import change_dir
 
 import coverage
 from coverage.backward import unicode_class
@@ -27,6 +26,7 @@ from coverage.report import get_analysis_to_report
 from tests.coveragetest import CoverageTest, TESTS_DIR
 from tests.goldtest import gold_path
 from tests.goldtest import compare, contains, doesnt_contain, contains_any
+from tests.helpers import change_dir
 
 
 class HtmlTestHelpers(CoverageTest):
diff --git a/tests/test_xml.py b/tests/test_xml.py
index 13e015d6..94669cdc 100644
--- a/tests/test_xml.py
+++ b/tests/test_xml.py
@@ -10,7 +10,6 @@ import re
 from xml.etree import ElementTree
 
 import pytest
-from unittest_mixins import change_dir
 
 import coverage
 from coverage.backward import import_local_file
@@ -18,6 +17,7 @@ from coverage.files import abs_file
 
 from tests.coveragetest import CoverageTest
 from tests.goldtest import compare, gold_path
+from tests.helpers import change_dir
 
 
 class XmlTestHelpers(CoverageTest):