def test_src_txt_immutability(self):
"""
Attempting to set `refmanage.NonbibFile.src_txt` should raise AttributeError
"""
b = NonbibFile(self.invalid)
try:
b.src_txt = "legitimate text string"
except AttributeError:
# Attempting to set `path` attribute raises an error; test passed!
pass
else:
self.fail("NonbibFile.src_txt can be set after instantiation")
