add tests for WaterPool class

tests/parameters/test_WaterPool.py

@@ -0,0 +1,68 @@
+import pytest
+
+from bmctool.parameters._WaterPool import WaterPool
+
+
+@pytest.mark.parametrize(
+    'r1, r2, f, t1, t2',
+    [
+        (1.0, 2.0, 1.0, None, None),  # all values float
+        (1.0, 2.0, 1, None, None),  # f int
+        (1.0, 2.0, '1', None, None),  # f str
+        (1.0, 2.0, '1e-0', None, None),  # f str (scientific notation)
+        (None, 2.0, 1.0, 1.0, None),  # r1 None, but t1 float
+        (None, 2.0, 1.0, '1.0', None),  # r1 None, but t1 str
+        (1.0, None, 1.0, None, 0.5),  # r2 None, but t2 float
+    ],
+)
+def test_from_valid_params(r1, r2, f, t1, t2):
+    """Test WaterPool instantiation from valid parameters."""
+    a = WaterPool(r1=r1, r2=r2, f=f, t1=t1, t2=t2)
+    assert isinstance(a, WaterPool)
+
+
+@pytest.mark.parametrize(
+    'r1, r2, f, t1, t2',
+    [
+        (1.0, 2.0, 0.3, 1.0, None),  # r1 and t1 both given
+        (None, 2.0, 0.3, None, None),  # neither r1 nor t1 given
+        (1.0, 2.0, 0.3, None, 0.5),  # r2 and t2 both given
+        (1.0, None, 0.3, None, None),  # neither r2 nor t2 given
+    ],
+)
+def test_from_invalid_combination(r1, r2, f, t1, t2):
+    """Test WaterPool instantiation from invalid parameter combinations."""
+    with pytest.raises(ValueError):
+        WaterPool(r1=r1, r2=r2, f=f, t1=t1, t2=t2)
+
+
+@pytest.mark.parametrize(
+    'r1, r2, f, t1, t2',
+    [
+        (1.0, 2.0, 3.0, None, None),  # f not between 0 and 1
+        (-1.0, 2.0, 0.3, None, None),  # r1 negative
+        (None, 2.0, 0.3, -1.0, None),  # t1 negative
+    ],
+)
+def test_from_invalid_values(r1, r2, f, t1, t2):
+    """Test WaterPool instantiation from invalid parameter types."""
+    with pytest.raises(ValueError):
+        WaterPool(r1=r1, r2=r2, f=f, t1=t1, t2=t2)
+
+
+def test_slots_property():
+    """Test that __slots__ is properly set."""
+    a = WaterPool(r1=1.0, r2=2.0, f=0.3)
+    with pytest.raises(AttributeError):
+        a.new_attr = 1.0
+
+
+def test_dw_is_zero():
+    a = WaterPool(r1=1.0, r2=2.0, f=1.0)
+    assert a.dw == 0
+
+
+def test_dw_cannot_be_changed():
+    a = WaterPool(r1=1.0, r2=2.0, f=1)
+    with pytest.raises(UserWarning):
+        a.dw = 0.5