diff --git a/swh/loader/tests/test_cli.py b/swh/loader/tests/test_cli.py
index bdc0a76..c9968f6 100644
--- a/swh/loader/tests/test_cli.py
+++ b/swh/loader/tests/test_cli.py
@@ -1,131 +1,133 @@
 # Copyright (C) 2019-2020 The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import datetime
 
 import pytest
 
 
 from swh.loader.cli import run, list, get_loader, SUPPORTED_LOADERS
 from swh.loader.package.loader import PackageLoader
 
 from click.formatting import HelpFormatter
 from click.testing import CliRunner
 
 
 def test_get_loader_wrong_input(swh_config):
     """Unsupported loader should raise
 
     """
     loader_type = "unknown"
     assert loader_type not in SUPPORTED_LOADERS
     with pytest.raises(ValueError, match="Invalid loader"):
         get_loader(loader_type, url="db-url")
 
 
 def test_get_loader(swh_config):
     """Instantiating a supported loader should be ok
 
     """
     loader_input = {
         "archive": {"url": "some-url", "artifacts": [],},
         "debian": {"url": "some-url", "date": "something", "packages": [],},
         "deposit": {"url": "some-url", "deposit_id": 1,},
         "npm": {"url": "https://www.npmjs.com/package/onepackage",},
         "pypi": {"url": "some-url",},
     }
     for loader_type, kwargs in loader_input.items():
         loader = get_loader(loader_type, **kwargs)
         assert isinstance(loader, PackageLoader)
 
 
 def _write_usage(command, args, max_width=80):
     hf = HelpFormatter(width=max_width)
     hf.write_usage(command, args)
     return hf.getvalue()[:-1]
 
 
 def test_run_help(swh_config):
     """Help message should be ok
 
     """
     runner = CliRunner()
     result = runner.invoke(run, ["-h"])
 
     assert result.exit_code == 0
     usage_prefix = _write_usage(
         "run", f"[OPTIONS] [{'|'.join(SUPPORTED_LOADERS)}] URL [OPTIONS]..."
     )
     expected_help_msg = f"""{usage_prefix}
 
   Ingest with loader <type> the origin located at <url>
 
 Options:
   -h, --help  Show this message and exit.
 """
     assert result.output.startswith(expected_help_msg)
 
 
 def test_run_pypi(mocker, swh_config):
     """Triggering a load should be ok
 
     """
     mock_loader = mocker.patch("swh.loader.package.pypi.loader.PyPILoader")
     runner = CliRunner()
     result = runner.invoke(run, ["pypi", "https://some-url"])
     assert result.exit_code == 0
     mock_loader.assert_called_once_with(url="https://some-url")  # constructor
 
 
 def test_run_with_visit_date(mocker, swh_config):
     """iso visit_date parameter should be parsed as datetime
 
     """
     mock_loader = mocker.patch("swh.loader.cli.get_loader")
 
     runner = CliRunner()
     input_date = "2016-05-03 15:16:32+00"
-    result = runner.invoke(run, ["npm", "https://some-url", f"visit_date={input_date}"])
+    result = runner.invoke(
+        run, ["npm", "https://some-url", f"visit_date='{input_date}'"]
+    )
     assert result.exit_code == 0
     expected_parsed_date = datetime.datetime(
         2016, 5, 3, 15, 16, 32, tzinfo=datetime.timezone.utc
     )
     mock_loader.assert_called_once_with(
         "npm", url="https://some-url", visit_date=expected_parsed_date
     )
 
 
 def test_list_help(mocker, swh_config):
     """Triggering a load should be ok
 
     """
     runner = CliRunner()
     result = runner.invoke(list, ["--help"])
     assert result.exit_code == 0
     usage_prefix = _write_usage(
         "list", f"[OPTIONS] [[{'|'.join(['all'] + SUPPORTED_LOADERS)}]]"
     )
     expected_help_msg = f"""{usage_prefix}
 
   List supported loaders and optionally their arguments
 
 Options:
   -h, --help  Show this message and exit.
 """
     assert result.output.startswith(expected_help_msg)
 
 
 def test_list_help_npm(mocker, swh_config):
     """Triggering a load should be ok
 
     """
     runner = CliRunner()
     result = runner.invoke(list, ["npm"])
     assert result.exit_code == 0
     expected_help_msg = """
 Loader: Load npm origin's artifact releases into swh archive.
 signature: (url: str)
 """
     assert result.output.startswith(expected_help_msg[1:])