refactor: Disallow value as string (#232)

* refactor: Disallow value as string

* add a test

* update error

Author: hpohekar

src/ansys/units/quantity.py

@@ -78,6 +78,8 @@ def __init__(
             raise InsufficientArguments()
 
         if not isinstance(value, (float, int)):
+            if isinstance(value, str):
+                raise TypeError("value should be either float, int or [float, int].")
             if _array:
                 if isinstance(value, _array.ndarray):
                     self._value = value

tests/test_quantity.py

@@ -589,3 +589,8 @@ def test_error_messages():
 
     e4 = RequiresUniqueDimensions(Unit("mm"), Unit("m"))
     assert str(e4) == "For 'mm' to be added 'm' must be removed."
+
+
+def test_value_as_string():
+    with pytest.raises(TypeError):
+        q = Quantity("string", "m")