You also need to be careful to create a copy of the DataFrame, otherwise the csvdata_old will be updated with csvdata (since it points to the same object):
csvdata_old = csvdata.copy()
To check whether they are equal, you can use assert_frame_equal as in this answer:
from pandas.util.testing import assert_frame_equal
assert_frame_equal(csvdata, csvdata_old)
You can wrap this in a function with something like:
try:
assert_frame_equal(csvdata, csvdata_old)
return True
except: # appeantly AssertionError doesn't catch all
return False
There was discussion of a better way…