Fix zipped file error

test/residual_test/Calculation_test.py

-from geomagio.residual import SpreadsheetAbsolutesFactory
-from numpy.testing import assert_almost_equal
-
-import os
-
-for filename in os.listdir("etc/residual")[1::]:
-    # establish SpreadsheetAbsolutesFactory for reading test data from Excel
-    saf = SpreadsheetAbsolutesFactory()
-    # Read spreadsheet containing test data
-    reading = saf.parse_spreadsheet("etc/residual/" + filename)
-    # establish original absolute object
-    original = reading.absolutes
-    # recalculate absolute object using Calculation.py
-    reading.update_absolutes()
-    # establish recalculated absolute object
-    result = reading.absolutes
-
-    for i in range(len(result)):
-        original_element = original[i]
-        result_element = result[i]
-        # gather elements' absolutes
-        o_absolute = original_element.absolute
-        r_absolute = result_element.absolute
-        # gather element's baselines
-        o_baseline = original_element.baseline
-        r_baseline = result_element.baseline
-        # test absolute values
-        assert_almost_equal(
-            o_absolute,
-            r_absolute,
-            decimal=4,
-            err_msg="Absolutes not within 4 decimals",
-            verbose=True,
-        )
-        # test baseline values
-        assert_almost_equal(
-            o_baseline,
-            r_baseline,
-            decimal=4,
-            err_msg="Baselines not within 4 decimals",
-            verbose=True,
-        )