diff --git a/tests/unit/core/test_bounds_checker.py b/tests/unit/core/test_bounds_checker.py
deleted file mode 100644
index cd9fb00c..00000000
--- a/tests/unit/core/test_bounds_checker.py
+++ /dev/null
@@ -1,120 +0,0 @@
-"""Tests the functions in bounds_checker.py."""
-
-from contextlib import nullcontext as does_not_raise
-
-import numpy as np
-import pytest
-
-
-@pytest.mark.parametrize(
-    argnames="input, raises, lowfn, hifun",
-    argvalues=[
-        ("[]", does_not_raise(), np.less, np.greater),
-        ("()", does_not_raise(), np.less_equal, np.greater_equal),
-        ("[)", does_not_raise(), np.less, np.greater_equal),
-        ("(]", does_not_raise(), np.less_equal, np.greater),
-        ("{}", pytest.raises(ValueError), None, None),
-    ],
-)
-def test__get_interval_functions(input, raises, lowfn, hifun):
-    """Tests _get_interval_functions."""
-
-    from pyrealm.core.utilities import _get_interval_functions
-
-    with raises as err:
-        low, hi = _get_interval_functions(input)
-
-    if not err:
-        assert low == lowfn
-        assert hi == hifun
-
-
-@pytest.mark.parametrize(
-    argnames="input, interval_args, context",
-    argvalues=[
-        (3, (1, 4, "()"), does_not_raise()),
-        (np.array([1, 2, 3, 4]), (1.0, 4.0, "()"), pytest.warns(UserWarning)),
-        (np.array([1, 2, 3, 4]), (0.9, 4.1, "()"), does_not_raise()),
-        (np.array([1, 2, 3, 4]), (1.1, 3.9, "[]"), pytest.warns(UserWarning)),
-        (np.array([1, 2, 3, 4]), (1.0, 4.0, "[]"), does_not_raise()),
-        (np.array([1, 2, 3, 4]), (1.0, 4.0, "[)"), pytest.warns(UserWarning)),
-        (np.array([1, 2, 3, 4]), (1.0, 4.1, "[)"), does_not_raise()),
-        (np.array([1, 2, 3, 4]), (1.0, 4.0, "(]"), pytest.warns(UserWarning)),
-        (np.array([1, 2, 3, 4]), (0.9, 4.0, "(]"), does_not_raise()),
-    ],
-)
-def test_bounds_checker(input, interval_args, context):
-    """The the bounds_checker utility raises warnings as expected."""
-    from pyrealm.core.utilities import bounds_checker
-
-    with context:
-        _ = bounds_checker(input, *interval_args)
-
-
-@pytest.mark.parametrize(
-    argnames="input, interval_args, context, exp",
-    argvalues=[
-        (
-            3,
-            (1, 4, "()"),
-            pytest.raises(TypeError),
-            None,
-        ),
-        (
-            np.array([1, 2, 3, 4]),
-            (1, 4, "()"),
-            pytest.warns(RuntimeWarning),
-            np.array([np.nan, 2, 3, np.nan]),
-        ),
-        (
-            np.array([1, 2, 3, 4]),
-            (0.9, 4.1, "()"),
-            does_not_raise(),
-            np.array([1, 2, 3, 4]),
-        ),
-        (
-            np.array([1, 2, 3, 4]),
-            (1.1, 3.9, "[]"),
-            pytest.warns(RuntimeWarning),
-            np.array([np.nan, 2, 3, np.nan]),
-        ),
-        (
-            np.array([1, 2, 3, 4]),
-            (1, 4, "[]"),
-            does_not_raise(),
-            np.array([1, 2, 3, 4]),
-        ),
-        (
-            np.array([1, 2, 3, 4]),
-            (1, 4, "[)"),
-            pytest.warns(RuntimeWarning),
-            np.array([1, 2, 3, np.nan]),
-        ),
-        (
-            np.array([1, 2, 3, 4]),
-            (1, 4.1, "[)"),
-            does_not_raise(),
-            np.array([1, 2, 3, 4]),
-        ),
-        (
-            np.array([1, 2, 3, 4]),
-            (1, 4, "(]"),
-            pytest.warns(RuntimeWarning),
-            np.array([np.nan, 2, 3, 4]),
-        ),
-        (
-            np.array([1, 2, 3, 4]),
-            (0.9, 4, "(]"),
-            does_not_raise(),
-            np.array([1, 2, 3, 4]),
-        ),
-    ],
-)
-def test_bounds_mask(input, interval_args, context, exp):
-    """Test the bounds_mask utility."""
-    from pyrealm.core.utilities import bounds_mask
-
-    with context:
-        out = bounds_mask(input, *interval_args)
-
-        assert np.allclose(out, exp, equal_nan=True)