Fix accidentally broken unit test

src/artemis/parameters/tests/test_external_parameters.py

@@ -53,12 +53,13 @@ def test_beamline_parameters():
  assert params["beamLineEnergy__adjustSlits"] is False
 
 
-def test_get_beamline_parameters():
+def test_get_beamline_parameters_works_with_no_environment_variable_set():
  if environ.get("BEAMLINE"):
  del environ["BEAMLINE"]
- with pytest.raises(KeyError) as excinfo:
- get_beamline_parameters()
- assert "environment variable is not set" in str(excinfo.value)
+ assert get_beamline_parameters()
+
+
+def test_get_beamline_parameters():
  environ["BEAMLINE"] = "i03"
  with patch.dict(
  "artemis.parameters.beamline_parameters.BEAMLINE_PARAMETER_PATHS",