[Python-checkins] bpo-32933: Implement __iter__ method on mock_open() (GH-5974)
Berker Peksag
webhook-mailer at python.org
Wed Sep 12 18:21:19 EDT 2018
https://github.com/python/cpython/commit/2087023fdec2c89070bd14f384a3c308c548a94a
commit: 2087023fdec2c89070bd14f384a3c308c548a94a
branch: master
author: Tony Flury <anthony.flury at btinternet.com>
committer: Berker Peksag <berker.peksag at gmail.com>
date: 2018-09-13T01:21:16+03:00
summary:
bpo-32933: Implement __iter__ method on mock_open() (GH-5974)
files:
A Misc/NEWS.d/next/Library/2018-04-30-22-43-31.bpo-32933.M3iI_y.rst
M Doc/library/unittest.mock.rst
M Lib/unittest/mock.py
M Lib/unittest/test/testmock/testmock.py
M Lib/unittest/test/testmock/testwith.py
diff --git a/Doc/library/unittest.mock.rst b/Doc/library/unittest.mock.rst
index fd4e067546e5..d1b18d08f797 100644
--- a/Doc/library/unittest.mock.rst
+++ b/Doc/library/unittest.mock.rst
@@ -2095,6 +2095,10 @@ mock_open
.. versionchanged:: 3.5
*read_data* is now reset on each call to the *mock*.
+ .. versionchanged:: 3.8
+ Added :meth:`__iter__` to implementation so that iteration (such as in for
+ loops) correctly consumes *read_data*.
+
Using :func:`open` as a context manager is a great way to ensure your file handles
are closed properly and is becoming common::
diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py
index db1e642c00b7..83026e6f3bd3 100644
--- a/Lib/unittest/mock.py
+++ b/Lib/unittest/mock.py
@@ -2358,14 +2358,16 @@ def _read_side_effect(*args, **kwargs):
return type(read_data)().join(_state[0])
def _readline_side_effect():
+ yield from _iter_side_effect()
+ while True:
+ yield type(read_data)()
+
+ def _iter_side_effect():
if handle.readline.return_value is not None:
while True:
yield handle.readline.return_value
for line in _state[0]:
yield line
- while True:
- yield type(read_data)()
-
global file_spec
if file_spec is None:
@@ -2389,6 +2391,7 @@ def _readline_side_effect():
_state[1] = _readline_side_effect()
handle.readline.side_effect = _state[1]
handle.readlines.side_effect = _readlines_side_effect
+ handle.__iter__.side_effect = _iter_side_effect
def reset_data(*args, **kwargs):
_state[0] = _iterate_read_data(read_data)
diff --git a/Lib/unittest/test/testmock/testmock.py b/Lib/unittest/test/testmock/testmock.py
index b64c8663d212..c7bfa277b511 100644
--- a/Lib/unittest/test/testmock/testmock.py
+++ b/Lib/unittest/test/testmock/testmock.py
@@ -1450,6 +1450,16 @@ def test_mock_open_reuse_issue_21750(self):
f2_data = f2.read()
self.assertEqual(f1_data, f2_data)
+ def test_mock_open_dunder_iter_issue(self):
+ # Test dunder_iter method generates the expected result and
+ # consumes the iterator.
+ mocked_open = mock.mock_open(read_data='Remarkable\nNorwegian Blue')
+ f1 = mocked_open('a-name')
+ lines = [line for line in f1]
+ self.assertEqual(lines[0], 'Remarkable\n')
+ self.assertEqual(lines[1], 'Norwegian Blue')
+ self.assertEqual(list(f1), [])
+
def test_mock_open_write(self):
# Test exception in file writing write()
mock_namedtemp = mock.mock_open(mock.MagicMock(name='JLV'))
diff --git a/Lib/unittest/test/testmock/testwith.py b/Lib/unittest/test/testmock/testwith.py
index a7bee7300301..43b36a119952 100644
--- a/Lib/unittest/test/testmock/testwith.py
+++ b/Lib/unittest/test/testmock/testwith.py
@@ -188,6 +188,7 @@ def test_read_data(self):
def test_readline_data(self):
# Check that readline will return all the lines from the fake file
+ # And that once fully consumed, readline will return an empty string.
mock = mock_open(read_data='foo\nbar\nbaz\n')
with patch('%s.open' % __name__, mock, create=True):
h = open('bar')
@@ -197,6 +198,7 @@ def test_readline_data(self):
self.assertEqual(line1, 'foo\n')
self.assertEqual(line2, 'bar\n')
self.assertEqual(line3, 'baz\n')
+ self.assertEqual(h.readline(), '')
# Check that we properly emulate a file that doesn't end in a newline
mock = mock_open(read_data='foo')
@@ -204,6 +206,19 @@ def test_readline_data(self):
h = open('bar')
result = h.readline()
self.assertEqual(result, 'foo')
+ self.assertEqual(h.readline(), '')
+
+
+ def test_dunder_iter_data(self):
+ # Check that dunder_iter will return all the lines from the fake file.
+ mock = mock_open(read_data='foo\nbar\nbaz\n')
+ with patch('%s.open' % __name__, mock, create=True):
+ h = open('bar')
+ lines = [l for l in h]
+ self.assertEqual(lines[0], 'foo\n')
+ self.assertEqual(lines[1], 'bar\n')
+ self.assertEqual(lines[2], 'baz\n')
+ self.assertEqual(h.readline(), '')
def test_readlines_data(self):
diff --git a/Misc/NEWS.d/next/Library/2018-04-30-22-43-31.bpo-32933.M3iI_y.rst b/Misc/NEWS.d/next/Library/2018-04-30-22-43-31.bpo-32933.M3iI_y.rst
new file mode 100644
index 000000000000..4de7a8f927d5
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-04-30-22-43-31.bpo-32933.M3iI_y.rst
@@ -0,0 +1,2 @@
+:func:`unittest.mock.mock_open` now supports iteration over the file
+contents. Patch by Tony Flury.
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