Fix error message format from get_pdb_code()

If the given PDB code does not exist, the error
reported was previously incorrectly formatted.
Fix and test for the right wording.

python/saliweb/frontend/__init__.py

@@ -548,8 +548,8 @@ def get_pdb_code(code, outdir):
     in_pdb, out_pdb = _get_pdb_paths(code)
     if not os.path.exists(in_pdb):
         raise InputValidationError(
-            "PDB code '%s' does not exist in our copy of the PDB database.",
-            code)
+            "PDB code '%s' does not exist in our copy of the PDB database."
+            % code)
     out_pdb = os.path.join(outdir, out_pdb)
     fh_in = gzip.open(in_pdb, 'rb')
     with open(out_pdb, 'wb') as fh_out:

test/pyfrontend/test_frontend.py

@@ -589,8 +589,11 @@ def __init__(self, tmpdir):
             flask.current_app = MockApp(tmpdir)
             self.assertRaises(saliweb.frontend.InputValidationError,
                               saliweb.frontend.get_pdb_code, "1@bc", tmpdir)
-            self.assertRaises(saliweb.frontend.InputValidationError,
-                              saliweb.frontend.get_pdb_code, "1aaaaaa", tmpdir)
+            with self.assertRaises(saliweb.frontend.InputValidationError) as cm:
+                saliweb.frontend.get_pdb_code("1aaaaaa", tmpdir)
+            self.assertEqual(str(cm.exception),
+                             "PDB code '1aaaaaa' does not exist in our copy "
+                             "of the PDB database.")
             self.assertFalse(saliweb.frontend.pdb_code_exists('1aaaaaa'))
             self.assertTrue(saliweb.frontend.pdb_code_exists('1xyz'))
             p = saliweb.frontend.get_pdb_code('1xyz', tmpdir)