Clean up test_shutil, to facilitate upcoming improvements (#12721).

The tests now have two convenience functions to wrap os.path.join, open
and read or write instead of four or six slightly different functions.
The new functions accept a tuple of path segments but not a list
anymore, as it makes no sense to use a list here; I have also removed
the default value for the contents in write_file, as I find it better to
have the contents at the call site.

For simple open then read/write calls, I have left the usual idiom (with
open + read/write), as it is short and readable enough.

I’ve also changed some convoluted cleanup code to just use rmtree, and
removed dubious LBYL os.path.exists checks.  The tests still pass on my
machine, and leave no file in $TMP.  test_shutil is not as clean as it
could be, but I’ll stop here.

Initial patch provided by Hynek Schlawack, in preparation for a new
feature with new tests in #12715.

1 files changed, 69 insertions, 96 deletions

diff --git a/Lib/test/test_shutil.py b/Lib/test/test_shutil.py
index b64cc3a..792b6cd 100644
--- a/Lib/test/test_shutil.py
+++ b/Lib/test/test_shutil.py
@@ -59,6 +59,31 @@ def mock_rename(func):
             os.rename = builtin_rename
     return wrap
 
+def write_file(path, content, binary=False):
+    """Write *content* to a file located at *path*.
+
+    If *path* is a tuple instead of a string, os.path.join will be used to
+    make a path.  If *binary* is true, the file will be opened in binary
+    mode.
+    """
+    if isinstance(path, tuple):
+        path = os.path.join(*path)
+    with open(path, 'wb' if binary else 'w') as fp:
+        fp.write(content)
+
+def read_file(path, binary=False):
+    """Return contents from a file located at *path*.
+
+    If *path* is a tuple instead of a string, os.path.join will be used to
+    make a path.  If *binary* is true, the file will be opened in binary
+    mode.
+    """
+    if isinstance(path, tuple):
+        path = os.path.join(*path)
+    with open(path, 'rb' if binary else 'r') as fp:
+        return fp.read()
+
+
 class TestShutil(unittest.TestCase):
 
     def setUp(self):
@@ -71,19 +96,6 @@ class TestShutil(unittest.TestCase):
             d = self.tempdirs.pop()
             shutil.rmtree(d, os.name in ('nt', 'cygwin'))
 
-    def write_file(self, path, content='xxx'):
-        """Writes a file in the given path.
-
-
-        path can be a string or a sequence.
-        """
-        if isinstance(path, (list, tuple)):
-            path = os.path.join(*path)
-        f = open(path, 'w')
-        try:
-            f.write(content)
-        finally:
-            f.close()
 
     def mkdtemp(self):
         """Create a temporary directory that will be cleaned up.
@@ -159,77 +171,42 @@ class TestShutil(unittest.TestCase):
         self.assertRaises(OSError, shutil.rmtree, path)
         os.remove(path)
 
-    def _write_data(self, path, data):
-        f = open(path, "w")
-        f.write(data)
-        f.close()
-
     def test_copytree_simple(self):
-
-        def read_data(path):
-            f = open(path)
-            data = f.read()
-            f.close()
-            return data
-
         src_dir = tempfile.mkdtemp()
         dst_dir = os.path.join(tempfile.mkdtemp(), 'destination')
-        self._write_data(os.path.join(src_dir, 'test.txt'), '123')
+        self.addCleanup(shutil.rmtree, src_dir)
+        self.addCleanup(shutil.rmtree, os.path.dirname(dst_dir))
+        write_file((src_dir, 'test.txt'), '123')
         os.mkdir(os.path.join(src_dir, 'test_dir'))
-        self._write_data(os.path.join(src_dir, 'test_dir', 'test.txt'), '456')
-
-        try:
-            shutil.copytree(src_dir, dst_dir)
-            self.assertTrue(os.path.isfile(os.path.join(dst_dir, 'test.txt')))
-            self.assertTrue(os.path.isdir(os.path.join(dst_dir, 'test_dir')))
-            self.assertTrue(os.path.isfile(os.path.join(dst_dir, 'test_dir',
-                                                        'test.txt')))
-            actual = read_data(os.path.join(dst_dir, 'test.txt'))
-            self.assertEqual(actual, '123')
-            actual = read_data(os.path.join(dst_dir, 'test_dir', 'test.txt'))
-            self.assertEqual(actual, '456')
-        finally:
-            for path in (
-                    os.path.join(src_dir, 'test.txt'),
-                    os.path.join(dst_dir, 'test.txt'),
-                    os.path.join(src_dir, 'test_dir', 'test.txt'),
-                    os.path.join(dst_dir, 'test_dir', 'test.txt'),
-                ):
-                if os.path.exists(path):
-                    os.remove(path)
-            for path in (src_dir,
-                    os.path.dirname(dst_dir)
-                ):
-                if os.path.exists(path):
-                    shutil.rmtree(path)
+        write_file((src_dir, 'test_dir', 'test.txt'), '456')
+
+        shutil.copytree(src_dir, dst_dir)
+        self.assertTrue(os.path.isfile(os.path.join(dst_dir, 'test.txt')))
+        self.assertTrue(os.path.isdir(os.path.join(dst_dir, 'test_dir')))
+        self.assertTrue(os.path.isfile(os.path.join(dst_dir, 'test_dir',
+                                                    'test.txt')))
+        actual = read_file((dst_dir, 'test.txt'))
+        self.assertEqual(actual, '123')
+        actual = read_file((dst_dir, 'test_dir', 'test.txt'))
+        self.assertEqual(actual, '456')
 
     def test_copytree_with_exclude(self):
-
-        def read_data(path):
-            f = open(path)
-            data = f.read()
-            f.close()
-            return data
-
         # creating data
         join = os.path.join
         exists = os.path.exists
         src_dir = tempfile.mkdtemp()
         try:
             dst_dir = join(tempfile.mkdtemp(), 'destination')
-            self._write_data(join(src_dir, 'test.txt'), '123')
-            self._write_data(join(src_dir, 'test.tmp'), '123')
+            write_file((src_dir, 'test.txt'), '123')
+            write_file((src_dir, 'test.tmp'), '123')
             os.mkdir(join(src_dir, 'test_dir'))
-            self._write_data(join(src_dir, 'test_dir', 'test.txt'), '456')
+            write_file((src_dir, 'test_dir', 'test.txt'), '456')
             os.mkdir(join(src_dir, 'test_dir2'))
-            self._write_data(join(src_dir, 'test_dir2', 'test.txt'), '456')
+            write_file((src_dir, 'test_dir2', 'test.txt'), '456')
             os.mkdir(join(src_dir, 'test_dir2', 'subdir'))
             os.mkdir(join(src_dir, 'test_dir2', 'subdir2'))
-            self._write_data(join(src_dir, 'test_dir2', 'subdir', 'test.txt'),
-                             '456')
-            self._write_data(join(src_dir, 'test_dir2', 'subdir2', 'test.py'),
-                             '456')
-
+            write_file((src_dir, 'test_dir2', 'subdir', 'test.txt'), '456')
+            write_file((src_dir, 'test_dir2', 'subdir2', 'test.py'), '456')
 
             # testing glob-like patterns
             try:
@@ -237,21 +214,19 @@ class TestShutil(unittest.TestCase):
                 shutil.copytree(src_dir, dst_dir, ignore=patterns)
                 # checking the result: some elements should not be copied
                 self.assertTrue(exists(join(dst_dir, 'test.txt')))
-                self.assertTrue(not exists(join(dst_dir, 'test.tmp')))
-                self.assertTrue(not exists(join(dst_dir, 'test_dir2')))
+                self.assertFalse(exists(join(dst_dir, 'test.tmp')))
+                self.assertFalse(exists(join(dst_dir, 'test_dir2')))
             finally:
-                if os.path.exists(dst_dir):
-                    shutil.rmtree(dst_dir)
+                shutil.rmtree(dst_dir)
             try:
                 patterns = shutil.ignore_patterns('*.tmp', 'subdir*')
                 shutil.copytree(src_dir, dst_dir, ignore=patterns)
                 # checking the result: some elements should not be copied
-                self.assertTrue(not exists(join(dst_dir, 'test.tmp')))
-                self.assertTrue(not exists(join(dst_dir, 'test_dir2', 'subdir2')))
-                self.assertTrue(not exists(join(dst_dir, 'test_dir2', 'subdir')))
+                self.assertFalse(exists(join(dst_dir, 'test.tmp')))
+                self.assertFalse(exists(join(dst_dir, 'test_dir2', 'subdir2')))
+                self.assertFalse(exists(join(dst_dir, 'test_dir2', 'subdir')))
             finally:
-                if os.path.exists(dst_dir):
-                    shutil.rmtree(dst_dir)
+                shutil.rmtree(dst_dir)
 
             # testing callable-style
             try:
@@ -270,13 +245,12 @@ class TestShutil(unittest.TestCase):
                 shutil.copytree(src_dir, dst_dir, ignore=_filter)
 
                 # checking the result: some elements should not be copied
-                self.assertTrue(not exists(join(dst_dir, 'test_dir2', 'subdir2',
-                                        'test.py')))
-                self.assertTrue(not exists(join(dst_dir, 'test_dir2', 'subdir')))
+                self.assertFalse(exists(join(dst_dir, 'test_dir2', 'subdir2',
+                                             'test.py')))
+                self.assertFalse(exists(join(dst_dir, 'test_dir2', 'subdir')))
 
             finally:
-                if os.path.exists(dst_dir):
-                    shutil.rmtree(dst_dir)
+                shutil.rmtree(dst_dir)
         finally:
             shutil.rmtree(src_dir)
             shutil.rmtree(os.path.dirname(dst_dir))
@@ -371,9 +345,9 @@ class TestShutil(unittest.TestCase):
 
         src_dir = self.mkdtemp()
         dst_dir = os.path.join(self.mkdtemp(), 'destination')
-        self._write_data(os.path.join(src_dir, 'test.txt'), '123')
+        write_file((src_dir, 'test.txt'), '123')
         os.mkdir(os.path.join(src_dir, 'test_dir'))
-        self._write_data(os.path.join(src_dir, 'test_dir', 'test.txt'), '456')
+        write_file((src_dir, 'test_dir', 'test.txt'), '456')
 
         copied = []
         def _copy(src, dst):
@@ -390,7 +364,7 @@ class TestShutil(unittest.TestCase):
         dst_dir = os.path.join(self.mkdtemp(), 'destination')
         os.symlink('IDONTEXIST', os.path.join(src_dir, 'test.txt'))
         os.mkdir(os.path.join(src_dir, 'test_dir'))
-        self._write_data(os.path.join(src_dir, 'test_dir', 'test.txt'), '456')
+        write_file((src_dir, 'test_dir', 'test.txt'), '456')
         self.assertRaises(Error, shutil.copytree, src_dir, dst_dir)
 
         # a dangling symlink is ignored with the proper flag
@@ -406,7 +380,7 @@ class TestShutil(unittest.TestCase):
     def _copy_file(self, method):
         fname = 'test.txt'
         tmpdir = self.mkdtemp()
-        self.write_file([tmpdir, fname])
+        write_file((tmpdir, fname), 'xxx')
         file1 = os.path.join(tmpdir, fname)
         tmpdir2 = self.mkdtemp()
         method(file1, tmpdir2)
@@ -442,10 +416,10 @@ class TestShutil(unittest.TestCase):
     def test_make_tarball(self):
         # creating something to tar
         tmpdir = self.mkdtemp()
-        self.write_file([tmpdir, 'file1'], 'xxx')
-        self.write_file([tmpdir, 'file2'], 'xxx')
+        write_file((tmpdir, 'file1'), 'xxx')
+        write_file((tmpdir, 'file2'), 'xxx')
         os.mkdir(os.path.join(tmpdir, 'sub'))
-        self.write_file([tmpdir, 'sub', 'file3'], 'xxx')
+        write_file((tmpdir, 'sub', 'file3'), 'xxx')
 
         tmpdir2 = self.mkdtemp()
         # force shutil to create the directory
@@ -492,10 +466,10 @@ class TestShutil(unittest.TestCase):
         tmpdir = self.mkdtemp()
         dist = os.path.join(tmpdir, 'dist')
         os.mkdir(dist)
-        self.write_file([dist, 'file1'], 'xxx')
-        self.write_file([dist, 'file2'], 'xxx')
+        write_file((dist, 'file1'), 'xxx')
+        write_file((dist, 'file2'), 'xxx')
         os.mkdir(os.path.join(dist, 'sub'))
-        self.write_file([dist, 'sub', 'file3'], 'xxx')
+        write_file((dist, 'sub', 'file3'), 'xxx')
         os.mkdir(os.path.join(dist, 'sub2'))
         tmpdir2 = self.mkdtemp()
         base_name = os.path.join(tmpdir2, 'archive')
@@ -561,8 +535,8 @@ class TestShutil(unittest.TestCase):
     def test_make_zipfile(self):
         # creating something to tar
         tmpdir = self.mkdtemp()
-        self.write_file([tmpdir, 'file1'], 'xxx')
-        self.write_file([tmpdir, 'file2'], 'xxx')
+        write_file((tmpdir, 'file1'), 'xxx')
+        write_file((tmpdir, 'file2'), 'xxx')
 
         tmpdir2 = self.mkdtemp()
         # force shutil to create the directory
@@ -969,8 +943,7 @@ class TestCopyFile(unittest.TestCase):
             shutil.move(self.src_dir, dst_dir)
             self.assertTrue(os.path.isdir(dst_dir))
         finally:
-            if os.path.exists(dst_dir):
-                os.rmdir(dst_dir)
+            os.rmdir(dst_dir)