Add additional checks and tests (#81)

* Add additional checks and tests

* Update src/nomad_measurements/utils.py

Co-authored-by: Hampus Näsström <[email protected]>

* Edit docstring and remove redundant test

---------

Co-authored-by: Hampus Näsström <[email protected]>

src/nomad_measurements/utils.py

@@ -118,6 +118,7 @@ def to_pint_quantity(value: Any=None, unit: str=None) -> Any:
     '''
     Attempts to generate a pint quantity.
     In case the value is a string, it is returned as is.
+    If the value is a pint quantity, it is converted to the given unit.
 
     Args:
         value (Any): Value of the quantity.
@@ -126,6 +127,10 @@ def to_pint_quantity(value: Any=None, unit: str=None) -> Any:
     Returns:
         Any: Processed quantity with datatype depending on the value.
     '''
-    if isinstance(value, str):
+    if isinstance(value, str) or value is None:
         return value
+    if isinstance(value, ureg.Quantity):
+        if unit is None:
+            return value
+        return value.to(unit)
     return value * ureg(unit)

tests/test_utils.py

@@ -56,12 +56,19 @@ def test_merge_sections():
     assert system_3.components[0].name == 'Cu'
 
 def test_to_pint_quantity():
-    assert to_pint_quantity(1, 'mA') == 1 * ureg.mA
+    assert to_pint_quantity(None, None) is None
+    assert to_pint_quantity(None, 'mA') is None
+    assert to_pint_quantity('Copper', '') == 'Copper'
+    assert to_pint_quantity('Copper', 'mA') == 'Copper'
+    assert to_pint_quantity(3., '') == 3 * ureg.dimensionless
+    assert to_pint_quantity(3. * ureg.m, None) == 3 * ureg.m
+    assert to_pint_quantity(3. * ureg.m, 'cm') == 300 * ureg.cm
+    assert to_pint_quantity(1, None) == 1
     assert (to_pint_quantity(np.asarray([1., 2.]), 'm') \
         == np.asarray([1., 2.]) * ureg.m).all()
     assert (to_pint_quantity(np.asarray([1., 2.]), '') \
-        == np.asarray([1., 2.])).all()
-    assert to_pint_quantity('Copper', '') == 'Copper'
+        == np.asarray([1., 2.]) * ureg.dimensionless).all()
+    assert to_pint_quantity(1, 'mA') == 1 * ureg.mA
 
 if __name__ == '__main__':
     test_merge_sections()