Closes issue 17467. Add readline and readlines support to unittest.mock.mock_open
diff --git a/Lib/unittest/test/testmock/testwith.py b/Lib/unittest/test/testmock/testwith.py
index 0a0cfad..f54e051 100644
--- a/Lib/unittest/test/testmock/testwith.py
+++ b/Lib/unittest/test/testmock/testwith.py
@@ -172,5 +172,88 @@
self.assertEqual(result, 'foo')
+ def test_readline_data(self):
+ # Check that readline 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')
+ line1 = h.readline()
+ line2 = h.readline()
+ line3 = h.readline()
+ self.assertEqual(line1, 'foo\n')
+ self.assertEqual(line2, 'bar\n')
+ self.assertEqual(line3, 'baz\n')
+
+ # Check that we properly emulate a file that doesn't end in a newline
+ mock = mock_open(read_data='foo')
+ with patch('%s.open' % __name__, mock, create=True):
+ h = open('bar')
+ result = h.readline()
+ self.assertEqual(result, 'foo')
+
+
+ def test_readlines_data(self):
+ # Test that emulating a file that ends in a newline character works
+ mock = mock_open(read_data='foo\nbar\nbaz\n')
+ with patch('%s.open' % __name__, mock, create=True):
+ h = open('bar')
+ result = h.readlines()
+ self.assertEqual(result, ['foo\n', 'bar\n', 'baz\n'])
+
+ # Test that files without a final newline will also be correctly
+ # emulated
+ mock = mock_open(read_data='foo\nbar\nbaz')
+ with patch('%s.open' % __name__, mock, create=True):
+ h = open('bar')
+ result = h.readlines()
+
+ self.assertEqual(result, ['foo\n', 'bar\n', 'baz'])
+
+
+ def test_mock_open_read_with_argument(self):
+ # At one point calling read with an argument was broken
+ # for mocks returned by mock_open
+ some_data = 'foo\nbar\nbaz'
+ mock = mock_open(read_data=some_data)
+ self.assertEqual(mock().read(10), some_data)
+
+
+ def test_interleaved_reads(self):
+ # Test that calling read, readline, and readlines pulls data
+ # sequentially from the data we preload with
+ mock = mock_open(read_data='foo\nbar\nbaz\n')
+ with patch('%s.open' % __name__, mock, create=True):
+ h = open('bar')
+ line1 = h.readline()
+ rest = h.readlines()
+ self.assertEqual(line1, 'foo\n')
+ self.assertEqual(rest, ['bar\n', 'baz\n'])
+
+ mock = mock_open(read_data='foo\nbar\nbaz\n')
+ with patch('%s.open' % __name__, mock, create=True):
+ h = open('bar')
+ line1 = h.readline()
+ rest = h.read()
+ self.assertEqual(line1, 'foo\n')
+ self.assertEqual(rest, 'bar\nbaz\n')
+
+
+ def test_overriding_return_values(self):
+ mock = mock_open(read_data='foo')
+ handle = mock()
+
+ handle.read.return_value = 'bar'
+ handle.readline.return_value = 'bar'
+ handle.readlines.return_value = ['bar']
+
+ self.assertEqual(handle.read(), 'bar')
+ self.assertEqual(handle.readline(), 'bar')
+ self.assertEqual(handle.readlines(), ['bar'])
+
+ # call repeatedly to check that a StopIteration is not propagated
+ self.assertEqual(handle.readline(), 'bar')
+ self.assertEqual(handle.readline(), 'bar')
+
+
if __name__ == '__main__':
unittest.main()