Merge #15415 from 3.3

ncoghlan · ncoghlan · commit cf67b2a8916d · 2013-07-28T22:25:25.000+10:00
diff --git a/Doc/library/test.rst b/Doc/library/test.rst
@@ -387,18 +387,40 @@ The :mod:`test.support` module defines the following functions:
       self.assertEqual(captured, "hello")
 
 
-.. function:: temp_cwd(name='tempcwd', quiet=False, path=None)
+.. function:: temp_dir(path=None, quiet=False)
+
+   A context manager that creates a temporary directory at *path* and
+   yields the directory.
+
+   If *path* is None, the temporary directory is created using
+   :func:`tempfile.mkdtemp`.  If *quiet* is ``False``, the context manager
+   raises an exception on error.  Otherwise, if *path* is specified and
+   cannot be created, only a warning is issued.
+
+
+.. function:: change_cwd(path, quiet=False)
 
    A context manager that temporarily changes the current working
-   directory (CWD).
+   directory to *path* and yields the directory.
+
+   If *quiet* is ``False``, the context manager raises an exception
+   on error.  Otherwise, it issues only a warning and keeps the current
+   working directory the same.
+
+
+.. function:: temp_cwd(name='tempcwd', quiet=False)
+
+   A context manager that temporarily creates a new directory and
+   changes the current working directory (CWD).
 
-   An existing path may be provided as *path*, in which case this function
-   makes no changes to the file system.
+   The context manager creates a temporary directory in the current
+   directory with name *name* before temporarily changing the current
+   working directory.  If *name* is None, the temporary directory is
+   created using :func:`tempfile.mkdtemp`.
 
-   Otherwise, the new CWD is created in the current directory and it's named
-   *name*.  If *quiet* is ``False`` and it's not possible to create or
-   change the CWD, an error is raised.  If it's ``True``, only a warning
-   is raised and the original CWD is used.
+   If *quiet* is ``False`` and it is not possible to create or change
+   the CWD, an error is raised.  Otherwise, only a warning is raised
+   and the original CWD is used.
 
 
 .. function:: temp_umask(umask)
diff --git a/Lib/test/script_helper.py b/Lib/test/script_helper.py
@@ -13,7 +13,7 @@
 import zipfile
 
 from importlib.util import source_from_cache
-from test.support import make_legacy_pyc, strip_python_stderr
+from test.support import make_legacy_pyc, strip_python_stderr, temp_dir
 
 # Executing the interpreter in a subprocess
 def _assert_python(expected_success, *args, **env_vars):
@@ -77,16 +77,6 @@ def kill_python(p):
     subprocess._cleanup()
     return data
 
-# Script creation utilities
-@contextlib.contextmanager
-def temp_dir():
-    dirname = tempfile.mkdtemp()
-    dirname = os.path.realpath(dirname)
-    try:
-        yield dirname
-    finally:
-        shutil.rmtree(dirname)
-
 def make_script(script_dir, script_basename, source):
     script_filename = script_basename+os.extsep+'py'
     script_name = os.path.join(script_dir, script_filename)
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
@@ -740,45 +740,85 @@ def _is_ipv6_enabled():
 SAVEDCWD = os.getcwd()
 
 @contextlib.contextmanager
-def temp_cwd(name='tempcwd', quiet=False, path=None):
-    """
-    Context manager that temporarily changes the CWD.
+def temp_dir(path=None, quiet=False):
+    """Return a context manager that creates a temporary directory.
+
+    Arguments:
+
+      path: the directory to create temporarily.  If omitted or None,
+        defaults to creating a temporary directory using tempfile.mkdtemp.
 
-    An existing path may be provided as *path*, in which case this
-    function makes no changes to the file system.
+      quiet: if False (the default), the context manager raises an exception
+        on error.  Otherwise, if the path is specified and cannot be
+        created, only a warning is issued.
 
-    Otherwise, the new CWD is created in the current directory and it's
-    named *name*. If *quiet* is False (default) and it's not possible to
-    create or change the CWD, an error is raised.  If it's True, only a
-    warning is raised and the original CWD is used.
     """
-    saved_dir = os.getcwd()
-    is_temporary = False
+    dir_created = False
     if path is None:
-        path = name
+        path = tempfile.mkdtemp()
+        dir_created = True
+        path = os.path.realpath(path)
+    else:
         try:
-            os.mkdir(name)
-            is_temporary = True
+            os.mkdir(path)
+            dir_created = True
         except OSError:
             if not quiet:
                 raise
-            warnings.warn('tests may fail, unable to create temp CWD ' + name,
+            warnings.warn('tests may fail, unable to create temp dir: ' + path,
                           RuntimeWarning, stacklevel=3)
+    try:
+        yield path
+    finally:
+        if dir_created:
+            shutil.rmtree(path)
+
+@contextlib.contextmanager
+def change_cwd(path, quiet=False):
+    """Return a context manager that changes the current working directory.
+
+    Arguments:
+
+      path: the directory to use as the temporary current working directory.
+
+      quiet: if False (the default), the context manager raises an exception
+        on error.  Otherwise, it issues only a warning and keeps the current
+        working directory the same.
+
+    """
+    saved_dir = os.getcwd()
     try:
         os.chdir(path)
     except OSError:
         if not quiet:
             raise
-        warnings.warn('tests may fail, unable to change the CWD to ' + path,
+        warnings.warn('tests may fail, unable to change CWD to: ' + path,
                       RuntimeWarning, stacklevel=3)
     try:
         yield os.getcwd()
     finally:
         os.chdir(saved_dir)
-        if is_temporary:
-            rmtree(name)
 
 
+@contextlib.contextmanager
+def temp_cwd(name='tempcwd', quiet=False):
+    """
+    Context manager that temporarily creates and changes the CWD.
+
+    The function temporarily changes the current working directory
+    after creating a temporary directory in the current directory with
+    name *name*.  If *name* is None, the temporary directory is
+    created using tempfile.mkdtemp.
+
+    If *quiet* is False (default) and it is not possible to
+    create or change the CWD, an error is raised.  If *quiet* is True,
+    only a warning is raised and the original CWD is used.
+
+    """
+    with temp_dir(path=name, quiet=quiet) as temp_path:
+        with change_cwd(temp_path, quiet=quiet) as cwd_dir:
+            yield cwd_dir
+
 if hasattr(os, "umask"):
     @contextlib.contextmanager
     def temp_umask(umask):
diff --git a/Lib/test/test_cmd_line_script.py b/Lib/test/test_cmd_line_script.py
@@ -290,7 +290,7 @@ def test_issue8202(self):
         # Make sure package __init__ modules see "-m" in sys.argv0 while
         # searching for the module to execute
         with temp_dir() as script_dir:
-            with support.temp_cwd(path=script_dir):
+            with support.change_cwd(path=script_dir):
                 pkg_dir = os.path.join(script_dir, 'test_pkg')
                 make_pkg(pkg_dir, "import sys; print('init_argv0==%r' % sys.argv[0])")
                 script_name = _make_test_script(pkg_dir, 'script')
@@ -307,7 +307,7 @@ def test_issue8202_dash_c_file_ignored(self):
         # Make sure a "-c" file in the current directory
         # does not alter the value of sys.path[0]
         with temp_dir() as script_dir:
-            with support.temp_cwd(path=script_dir):
+            with support.change_cwd(path=script_dir):
                 with open("-c", "w") as f:
                     f.write("data")
                     rc, out, err = assert_python_ok('-c',
@@ -322,7 +322,7 @@ def test_issue8202_dash_m_file_ignored(self):
         # does not alter the value of sys.path[0]
         with temp_dir() as script_dir:
             script_name = _make_test_script(script_dir, 'other')
-            with support.temp_cwd(path=script_dir):
+            with support.change_cwd(path=script_dir):
                 with open("-m", "w") as f:
                     f.write("data")
                     rc, out, err = assert_python_ok('-m', 'other', *example_args)
@@ -335,7 +335,7 @@ def test_dash_m_error_code_is_one(self):
         # and results in an error that the return code to the
         # shell is '1'
         with temp_dir() as script_dir:
-            with support.temp_cwd(path=script_dir):
+            with support.change_cwd(path=script_dir):
                 pkg_dir = os.path.join(script_dir, 'test_pkg')
                 make_pkg(pkg_dir)
                 script_name = _make_test_script(pkg_dir, 'other',
diff --git a/Lib/test/test_shutil.py b/Lib/test/test_shutil.py
@@ -1318,18 +1318,18 @@ def test_relative_cmd(self):
         # that exists, it should be returned.
         base_dir, tail_dir = os.path.split(self.dir)
         relpath = os.path.join(tail_dir, self.file)
-        with support.temp_cwd(path=base_dir):
+        with support.change_cwd(path=base_dir):
             rv = shutil.which(relpath, path=self.temp_dir)
             self.assertEqual(rv, relpath)
         # But it shouldn't be searched in PATH directories (issue #16957).
-        with support.temp_cwd(path=self.dir):
+        with support.change_cwd(path=self.dir):
             rv = shutil.which(relpath, path=base_dir)
             self.assertIsNone(rv)
 
     def test_cwd(self):
         # Issue #16957
         base_dir = os.path.dirname(self.dir)
-        with support.temp_cwd(path=self.dir):
+        with support.change_cwd(path=self.dir):
             rv = shutil.which(self.file, path=base_dir)
             if sys.platform == "win32":
                 # Windows: current directory implicitly on PATH
@@ -1350,7 +1350,7 @@ def test_non_matching_mode(self):
 
     def test_relative_path(self):
         base_dir, tail_dir = os.path.split(self.dir)
-        with support.temp_cwd(path=base_dir):
+        with support.change_cwd(path=base_dir):
             rv = shutil.which(self.file, path=tail_dir)
             self.assertEqual(rv, os.path.join(tail_dir, self.file))
 
@@ -1375,7 +1375,7 @@ def test_environ_path(self):
 
     def test_empty_path(self):
         base_dir = os.path.dirname(self.dir)
-        with support.temp_cwd(path=self.dir), \
+        with support.change_cwd(path=self.dir), \
              support.EnvironmentVarGuard() as env:
             env['PATH'] = self.dir
             rv = shutil.which(self.file, path='')
diff --git a/Lib/test/test_support.py b/Lib/test/test_support.py
diff --git a/Misc/NEWS b/Misc/NEWS
