change local.path to str for test

tests/test_digest.py

@@ -369,7 +369,7 @@ def test_digest_from_input(capsys, tmpdir):
     # Test fasta file
     fasta_file = tmpdir.join("test.fasta")
     fasta_file.write(">Fake1\nWQSDESDFZQS\nDESDF\n>Fake2\nNPHARDORCOMPLET")
-    res = digest.digest_from_input(fasta_file, enzymes, mode)
+    res = digest.digest_from_input(str(fasta_file), enzymes, mode)
     assert res[0][0].__repr__() == "Number of cleavage: 4\nNumber of miss-cle"\
                                    "avage: 0\nPositions of miss-cleavage: []"\
                                    "\nRatio of miss-cleavage: 0.0\nPeptides: "\