Add support for rt, rt+, wt, wt+, at, at+ methods (#342)

* Update README.rst

* Update README.rst

* Update README.rst

* Implement seek over HTTPS

* Add 'rt' mode in API and test this mode.

* Add test api_rt_plus

* Add new mode for function 'open'.

* Revert "Merge remote-tracking branch 'remotes/upstream/master'"

This reverts commit ebeab51, reversing
changes made to 0f17449.

* Add test for binary mode:
- a
- a+
- at
- at+

* Update smart_open/tests/test_smart_open.py

Co-Authored-By: Michael Penkov <[email protected]>

* Add tempfile in tests.

* Add new mode function 'open'

* API test names updated.

* Delete "delete mode" in temp file

Co-Authored-By: Michael Penkov <[email protected]>

* Update smart_open/tests/test_smart_open.py

Co-Authored-By: Michael Penkov <[email protected]>

* Update smart_open/tests/test_smart_open.py

Co-Authored-By: Michael Penkov <[email protected]>

* Update test_read_str_from_bytes_api_a_plus
- read text

* Update tests api: when the text is compared, the text stream opens.

* Update tests api: update docstrings.

* remove unused variable buffer

* refactor unit tests

move tests that touch the file system to a separate fixture

* rename buffer to buf, avoid keyword as variable name

* add explicit rt and wt tests

* minor unit test improvements

smart_open/smart_open_lib.py

@@ -341,8 +341,11 @@ def open(
     #
     try:
         binary_mode = {'r': 'rb', 'r+': 'rb+',
+                       'rt': 'rb', 'rt+': 'rb+',
                        'w': 'wb', 'w+': 'wb+',
-                       'a': 'ab', 'a+': 'ab+'}[mode]
+                       'wt': 'wb', "wt+": 'wb+',
+                       'a': 'ab', 'a+': 'ab+',
+                       'at': 'ab', 'at+': 'ab+'}[mode]
     except KeyError:
         binary_mode = mode
     binary, filename = _open_binary_stream(uri, binary_mode, transport_params)

smart_open/tests/test_smart_open.py

@@ -263,10 +263,10 @@ def test_http_pass(self):
     def _test_compressed_http(self, suffix, query):
         """Can open <suffix> via http?"""
         raw_data = b'Hello World Compressed.' * 10000
-        buffer = make_buffer(name='data' + suffix)
-        with smart_open.smart_open(buffer, 'wb') as outfile:
+        buf = make_buffer(name='data' + suffix)
+        with smart_open.smart_open(buf, 'wb') as outfile:
             outfile.write(raw_data)
-        compressed_data = buffer.getvalue()
+        compressed_data = buf.getvalue()
         # check that the string was actually compressed
         self.assertNotEqual(compressed_data, raw_data)
 
@@ -296,13 +296,14 @@ def test_http_bz2_query(self):
         self._test_compressed_http(".bz2", True)
 
 
-def make_buffer(cls=six.BytesIO, initial_value=None, name=None):
+def make_buffer(cls=six.BytesIO, initial_value=None, name=None, noclose=False):
     """
-    Construct a new in-memory file object aka "buffer".
+    Construct a new in-memory file object aka "buf".
 
     :param cls: Class of the file object. Meaningful values are BytesIO and StringIO.
     :param initial_value: Passed directly to the constructor, this is the content of the returned buffer.
     :param name: Associated file path. Not assigned if is None (default).
+    :param noclose: If True, disables the .close function.
     :return: Instance of `cls`.
     """
     buf = cls(initial_value) if initial_value else cls()
@@ -311,71 +312,163 @@ def make_buffer(cls=six.BytesIO, initial_value=None, name=None):
     if six.PY2:
         buf.__enter__ = lambda: buf
         buf.__exit__ = lambda exc_type, exc_val, exc_tb: None
+    if noclose:
+        buf.close = lambda: None
     return buf
 
 
+class RealFileSystemTests(unittest.TestCase):
+    """Tests that touch the file system via temporary files."""
+
+    def setUp(self):
+        with tempfile.NamedTemporaryFile(prefix='test', delete=False) as fout:
+            fout.write(SAMPLE_BYTES)
+            self.temp_file = fout.name
+
+    def tearDown(self):
+        os.unlink(self.temp_file)
+
+    def test_rt(self):
+        with smart_open.smart_open(self.temp_file, 'rt') as fin:
+            data = fin.read()
+        self.assertEqual(data, SAMPLE_TEXT)
+
+    def test_wt(self):
+        #
+        # The file already contains SAMPLE_TEXT, so write something different.
+        #
+        text = 'nippon budokan'
+        with smart_open.smart_open(self.temp_file, 'wt') as fout:
+            fout.write(text)
+
+        with smart_open.smart_open(self.temp_file, 'rt') as fin:
+            data = fin.read()
+        self.assertEqual(data, text)
+
+    def test_ab(self):
+        with smart_open.smart_open(self.temp_file, 'ab') as fout:
+            fout.write(SAMPLE_BYTES)
+        with smart_open.smart_open(self.temp_file, 'rb') as fin:
+            data = fin.read()
+        self.assertEqual(data, SAMPLE_BYTES * 2)
+
+    def test_aplus(self):
+        with smart_open.smart_open(self.temp_file, 'a+') as fout:
+            fout.write(SAMPLE_TEXT)
+        with smart_open.smart_open(self.temp_file, 'rt') as fin:
+            text = fin.read()
+        self.assertEqual(text, SAMPLE_TEXT * 2)
+
+    def test_at(self):
+        with smart_open.smart_open(self.temp_file, 'at') as fout:
+            fout.write(SAMPLE_TEXT)
+        with smart_open.smart_open(self.temp_file, 'rt') as fin:
+            text = fin.read()
+        self.assertEqual(text, SAMPLE_TEXT * 2)
+
+    def test_atplus(self):
+        with smart_open.smart_open(self.temp_file, 'at+') as fout:
+            fout.write(SAMPLE_TEXT)
+        with smart_open.smart_open(self.temp_file, 'rt') as fin:
+            text = fin.read()
+        self.assertEqual(text, SAMPLE_TEXT * 2)
+
+
 class SmartOpenFileObjTest(unittest.TestCase):
     """
     Test passing raw file objects.
     """
 
     def test_read_bytes(self):
         """Can we read bytes from a byte stream?"""
-        buffer = make_buffer(initial_value=SAMPLE_BYTES)
-        with smart_open.smart_open(buffer, 'rb') as sf:
+        buf = make_buffer(initial_value=SAMPLE_BYTES)
+        with smart_open.smart_open(buf, 'rb') as sf:
             data = sf.read()
         self.assertEqual(data, SAMPLE_BYTES)
 
     def test_write_bytes(self):
         """Can we write bytes to a byte stream?"""
-        buffer = make_buffer()
-        with smart_open.smart_open(buffer, 'wb') as sf:
+        buf = make_buffer()
+        with smart_open.smart_open(buf, 'wb') as sf:
             sf.write(SAMPLE_BYTES)
-            self.assertEqual(buffer.getvalue(), SAMPLE_BYTES)
+            self.assertEqual(buf.getvalue(), SAMPLE_BYTES)
 
     @unittest.skipIf(six.PY2, "Python 2 does not differentiate between str and bytes")
     def test_read_text_stream_fails(self):
-        """Attempts to read directly from a text stream should fail."""
-        buffer = make_buffer(six.StringIO, initial_value=SAMPLE_TEXT)
-        with smart_open.smart_open(buffer, 'r') as sf:
+        """Attempts to read directly from a text stream should fail.
+
+        This is because smart_open.open expects a byte stream as input.
+        If you have a text stream, there's no point passing it to smart_open:
+        you can read from it directly.
+        """
+        buf = make_buffer(six.StringIO, initial_value=SAMPLE_TEXT)
+        with smart_open.smart_open(buf, 'r') as sf:
             self.assertRaises(TypeError, sf.read)  # we expect binary mode
 
     @unittest.skipIf(six.PY2, "Python 2 does not differentiate between str and bytes")
     def test_write_text_stream_fails(self):
         """Attempts to write directly to a text stream should fail."""
-        buffer = make_buffer(six.StringIO)
-        with smart_open.smart_open(buffer, 'w') as sf:
+        buf = make_buffer(six.StringIO)
+        with smart_open.smart_open(buf, 'w') as sf:
             self.assertRaises(TypeError, sf.write, SAMPLE_TEXT)  # we expect binary mode
 
-    def test_read_str_from_bytes(self):
-        """Can we read strings from a byte stream?"""
-        buffer = make_buffer(initial_value=SAMPLE_BYTES)
-        with smart_open.smart_open(buffer, 'r') as sf:
+    def test_read_text_from_bytestream(self):
+        buf = make_buffer(initial_value=SAMPLE_BYTES)
+        with smart_open.smart_open(buf, 'r') as sf:
+            data = sf.read()
+        self.assertEqual(data, SAMPLE_TEXT)
+
+    def test_read_text_from_bytestream_rt(self):
+        buf = make_buffer(initial_value=SAMPLE_BYTES)
+        with smart_open.smart_open(buf, 'rt') as sf:
             data = sf.read()
         self.assertEqual(data, SAMPLE_TEXT)
 
-    def test_write_str_to_bytes(self):
+    def test_read_text_from_bytestream_rtplus(self):
+        buf = make_buffer(initial_value=SAMPLE_BYTES)
+        with smart_open.smart_open(buf, 'rt+') as sf:
+            data = sf.read()
+        self.assertEqual(data, SAMPLE_TEXT)
+
+    def test_write_text_to_bytestream(self):
+        """Can we write strings to a byte stream?"""
+        buf = make_buffer(noclose=True)
+        with smart_open.smart_open(buf, 'w') as sf:
+            sf.write(SAMPLE_TEXT)
+
+        self.assertEqual(buf.getvalue(), SAMPLE_BYTES)
+
+    def test_write_text_to_bytestream_wt(self):
+        """Can we write strings to a byte stream?"""
+        buf = make_buffer(noclose=True)
+        with smart_open.smart_open(buf, 'wt') as sf:
+            sf.write(SAMPLE_TEXT)
+
+        self.assertEqual(buf.getvalue(), SAMPLE_BYTES)
+
+    def test_write_text_to_bytestream_wtplus(self):
         """Can we write strings to a byte stream?"""
-        buffer = make_buffer()
-        with smart_open.smart_open(buffer, 'w') as sf:
+        buf = make_buffer(noclose=True)
+        with smart_open.smart_open(buf, 'wt+') as sf:
             sf.write(SAMPLE_TEXT)
-            self.assertEqual(buffer.getvalue(), SAMPLE_BYTES)
+
+        self.assertEqual(buf.getvalue(), SAMPLE_BYTES)
 
     def test_name_read(self):
         """Can we use the "name" attribute to decompress on the fly?"""
         data = SAMPLE_BYTES * 1000
-        buffer = make_buffer(initial_value=bz2.compress(data), name='data.bz2')
-        with smart_open.smart_open(buffer, 'rb') as sf:
+        buf = make_buffer(initial_value=bz2.compress(data), name='data.bz2')
+        with smart_open.smart_open(buf, 'rb') as sf:
             data = sf.read()
         self.assertEqual(data, data)
 
     def test_name_write(self):
         """Can we use the "name" attribute to compress on the fly?"""
         data = SAMPLE_BYTES * 1000
-        buffer = make_buffer(name='data.bz2')
-        with smart_open.smart_open(buffer, 'wb') as sf:
+        buf = make_buffer(name='data.bz2')
+        with smart_open.smart_open(buf, 'wb') as sf:
             sf.write(data)
-        self.assertEqual(bz2.decompress(buffer.getvalue()), data)
+        self.assertEqual(bz2.decompress(buf.getvalue()), data)
 
     def test_open_side_effect(self):
         """