def open_mock(content, **kwargs):
"""Mock's mock_open only supports read() and write() which is not very useful.
This context manager adds support for getting the value of what was written out
and for iterating through a file line by line."""
global file_spec
if file_spec is None:
# set on first use
if PY2:
file_spec = file
else:
import _io
file_spec = list(set(dir(_io.TextIOWrapper)).union(set(dir(_io.BytesIO))))
m = MagicMock(name='open', spec=open)
handle = MagicMock(spec=file_spec)
handle.__enter__.return_value = handle
m.return_value = handle
content_out = StringIO()
if PY2:
patch_module = "__builtin__.open"
else:
patch_module = "builtins.open"
with patch(patch_module, m, create=True, **kwargs) as mo:
stream = StringIO(content)
rv = mo.return_value
rv.write = lambda x: content_out.write(bytes(x, "utf-8"))
rv.content_out = lambda: content_out.getvalue()
rv.__iter__.return_value = iter(stream.readlines())
rv.read.return_value = stream.read()
yield rv
