Add parametrized testing for get_variables

tests/test_utils.py

@@ -16,6 +16,7 @@
 # limitations under the License.
 #
 
+import pytest
 import numpy as np
 
 from nomad.units import ureg
@@ -67,14 +68,26 @@ def test_is_not_representative():
 # ! Missing test for RusselSandersState (but this class will probably be deprecated)
 
 
-def test_get_variables():
+@pytest.mark.parametrize(
+    'variables, result, result_length',
+    [
+        (None, [], 0),
+        ([], [], 0),
+        ([Temperature()], [], 0),
+        ([Temperature(), Energy(n_points=4)], [Energy(n_points=4)], 1),
+        (
+            [Temperature(), Energy(n_points=2), Energy(n_points=10)],
+            [Energy(n_points=2), Energy(n_points=10)],
+            2,
+        ),
+        # TODO add testing when we have variables which inherit from another variable
+    ],
+)
+def test_get_variables(variables: list, result: list, result_length: int):
     """
     Test the `get_variables` utility function
     """
-    variables = [
-        Temperature(points=list(range(-3, 4)) * ureg.kelvin),
-        Energy(points=list(range(-3, 4)) * ureg.joule),
-    ]
     energies = get_variables(variables, Energy)
-    assert len(energies) == 1
-    assert np.allclose(energies[0].points.magnitude, [-3, -2, -1, 0, 1, 2, 3])
+    assert len(energies) == result_length
+    for i, energy in enumerate(energies):  # asserting energies == result does not work
+        assert energy.n_points == result[i].n_points