Fix utils.copy for copying files, add unit tests

`copy('', 'a/b.ext0', 'c/d.ext1')` is copying `a/b.ext0` into `c/d.ext1/b.ext0`
(creating folder `c/d.ext1` in the process) instead of `c/d.ext1`.
Bug introduced by e03cf3f517.

pelican/tests/test_utils.py

@@ -323,6 +323,99 @@ class TestUtils(LoggedTestCase):
         locale.setlocale(locale.LC_TIME, old_locale)
 
 
+class TestCopy(unittest.TestCase):
+    '''Tests the copy utility'''
+
+    def setUp(self):
+        self.root_dir = mkdtemp(prefix='pelicantests.')
+
+    def tearDown(self):
+        shutil.rmtree(self.root_dir)
+
+    def _create_file(self, *path):
+        with open(os.path.join(self.root_dir, *path), 'w') as f:
+            f.write('42\n')
+
+    def _create_dir(self, *path):
+        os.makedirs(os.path.join(self.root_dir, *path))
+
+    def _exist_file(self, *path):
+        path = os.path.join(self.root_dir, *path)
+        self.assertTrue(os.path.isfile(path), 'File does not exist: %s' % path)
+
+    def _exist_dir(self, *path):
+        path = os.path.join(self.root_dir, *path)
+        self.assertTrue(os.path.exists(path),
+                        'Directory does not exist: %s' % path)
+
+    def test_copy_file_same_path(self):
+        self._create_file('a.txt')
+        utils.copy('',
+                   os.path.join(self.root_dir, 'a.txt'),
+                   os.path.join(self.root_dir, 'b.txt')
+                   )
+        self._exist_file('b.txt')
+
+    def test_copy_file_different_path(self):
+        self._create_dir('a')
+        self._create_dir('b')
+        self._create_file('a', 'a.txt')
+        utils.copy('',
+                   os.path.join(self.root_dir, 'a', 'a.txt'),
+                   os.path.join(self.root_dir, 'b', 'b.txt')
+                   )
+        self._exist_dir('b')
+        self._exist_file('b', 'b.txt')
+
+    def test_copy_file_create_dirs(self):
+        self._create_file('a.txt')
+        utils.copy('',
+                   os.path.join(self.root_dir, 'a.txt'),
+                   os.path.join(self.root_dir, 'b0', 'b1', 'b2', 'b3', 'b.txt')
+                   )
+        self._exist_dir('b0')
+        self._exist_dir('b0', 'b1')
+        self._exist_dir('b0', 'b1', 'b2')
+        self._exist_dir('b0', 'b1', 'b2', 'b3')
+        self._exist_file('b0', 'b1', 'b2', 'b3', 'b.txt')
+
+    def test_copy_dir_same_path(self):
+        self._create_dir('a')
+        self._create_file('a', 'a.txt')
+        utils.copy('',
+                   os.path.join(self.root_dir, 'a'),
+                   os.path.join(self.root_dir, 'b')
+                   )
+        self._exist_dir('b')
+        self._exist_file('b', 'a.txt')
+
+    def test_copy_dir_different_path(self):
+        self._create_dir('a0')
+        self._create_dir('a0', 'a1')
+        self._create_file('a0', 'a1', 'a.txt')
+        self._create_dir('b0')
+        utils.copy('',
+                   os.path.join(self.root_dir, 'a0', 'a1'),
+                   os.path.join(self.root_dir, 'b0', 'b1')
+                   )
+        self._exist_dir('b0', 'b1')
+        self._exist_file('b0', 'b1', 'a.txt')
+
+    def test_copy_dir_create_dirs(self):
+        self._create_dir('a')
+        self._create_file('a', 'a.txt')
+        utils.copy('',
+                   os.path.join(self.root_dir, 'a'),
+                   os.path.join(self.root_dir, 'b0', 'b1', 'b2', 'b3', 'b')
+                   )
+        self._exist_dir('b0')
+        self._exist_dir('b0', 'b1')
+        self._exist_dir('b0', 'b1', 'b2')
+        self._exist_dir('b0', 'b1', 'b2', 'b3')
+        self._exist_dir('b0', 'b1', 'b2', 'b3', 'b')
+        self._exist_file('b0', 'b1', 'b2', 'b3', 'b', 'a.txt')
+
+
 class TestDateFormatter(unittest.TestCase):
     '''Tests that the output of DateFormatter jinja filter is same as
     utils.strftime'''

pelican/utils.py

@@ -273,7 +273,7 @@ def copy(path, source, destination, destination_path=None):
     destination_ = os.path.abspath(
         os.path.expanduser(os.path.join(destination, destination_path)))
 
-    if not os.path.exists(destination_):
+    if not os.path.exists(destination_) and not os.path.isfile(source_):
         os.makedirs(destination_)
 
     def recurse(source, destination):