adding the remainder of the missing test cases

tests/test_utility.py

@@ -8,3 +8,41 @@ def test_invalid_dimensionality_1d_array():
     with pytest.raises(ValueError, match="Image array must be 2D or 3D."):
         Utility._input_checker(invalid_1d_array)
 
+def test_invalid_dimensionality_4d_array():
+    invalid_4d_array = np.random.rand(2, 2, 2, 2)
+
+    with pytest.raises(ValueError, match="Image array must be 2D or 3D."):
+        Utility._input_checker(invalid_4d_array)
+
+def test_zero_size_array():
+    zero_size_array = np.array([])
+
+    with pytest.raises(ValueError, match="Image size must not be zero in any dimension."):
+        Utility._input_checker(zero_size_array)
+
+def test_zero_dimension_2d_array():
+    zero_dim_2d_array = np.empty((0, 10))
+
+    with pytest.raises(ValueError, match="Image size must not be zero in any dimension."):
+        Utility._input_checker(zero_dim_2d_array)
+
+def test_zero_dimension_3d_array():
+    zero_dim_3d_array = np.empty((0, 10, 3))
+
+    with pytest.raises(ValueError, match="Image size must not be zero in any dimension."):
+        Utility._input_checker(zero_dim_3d_array)
+
+def test_zero_dimension_multiple_axes():
+    zero_dim_multi_axis = np.empty((0, 0, 3))
+
+    with pytest.raises(ValueError, match="Image size must not be zero in any dimension."):
+        Utility._input_checker(zero_dim_multi_axis)
+
+def test_valid_2d_array():
+    valid_2d_array = np.random.rand(10, 10)
+
+    result = Utility._input_checker(valid_2d_array)
+    assert result
+
+def test_valid_3d_array():
+    valid_3d_array = np.random.rand(10, 10, 3)