feat: Add hash,eq and sizeof in ForwardLayer

src/safeds/ml/nn/_forward_layer.py

@@ -5,6 +5,7 @@
 if TYPE_CHECKING:
     from torch import Tensor, nn
 
+from safeds._utils import _structural_hash
 from safeds.exceptions import ClosedBound, OutOfBoundsError
 from safeds.ml.nn._layer import _Layer
 
@@ -88,3 +89,42 @@ def _set_input_size(self, input_size: int) -> None:
         if input_size < 1:
             raise OutOfBoundsError(actual=input_size, name="input_size", lower_bound=ClosedBound(1))
         self._input_size = input_size
+
+    def __hash__(self) -> int:
+        """
+        Return a deterministic hash value for this forward layer.
+
+        Returns
+        -------
+        hash:
+            the hash value
+        """
+        return _structural_hash(self._input_size, self._output_size)
+
+    def __eq__(self, other: object) -> bool:
+        """
+        Compare two forward layer instances.
+
+        Returns
+        -------
+        equals:
+            'True' if input and output size are equal, 'False' otherwise.
+        """
+        if not isinstance(other, ForwardLayer):
+            return NotImplemented
+        if self is other:
+            return True
+        return self._input_size == other._input_size and self._output_size == other._output_size
+
+    def __sizeof__(self) -> int:
+        import sys
+
+        """
+        Return the complete size of this object.
+
+        Returns
+        -------
+        size:
+            Size of this object in bytes.
+        """
+        return sys.getsizeof(self._input_size) + sys.getsizeof(self._output_size)

tests/safeds/ml/nn/test_forward_layer.py

@@ -1,3 +1,6 @@
+import sys
+from typing import Any
+
 import pytest
 from safeds.exceptions import OutOfBoundsError
 from safeds.ml.nn import ForwardLayer
@@ -70,3 +73,81 @@ def test_should_raise_if_output_size_out_of_bounds(output_size: int) -> None:
 )
 def test_should_raise_if_output_size_doesnt_match(output_size: int) -> None:
     assert ForwardLayer(output_size=output_size, input_size=1).output_size == output_size
+
+
+@pytest.mark.parametrize(
+    ("layer1", "layer2", "equal"),
+    [
+        (
+            ForwardLayer(input_size=1, output_size=2),
+            ForwardLayer(input_size=1, output_size=2),
+            True,
+        ),
+        (
+            ForwardLayer(input_size=1, output_size=2),
+            ForwardLayer(input_size=2, output_size=1),
+            False,
+        ),
+    ],
+    ids=["equal", "not equal"],
+)
+def test_should_compare_forward_layers(layer1: ForwardLayer, layer2: ForwardLayer, equal: bool) -> None:
+    assert (layer1.__eq__(layer2)) == equal
+
+
+def test_should_assert_that_forward_layer_is_equal_to_itself() -> None:
+    layer = ForwardLayer(input_size=1, output_size=1)
+    assert layer.__eq__(layer)
+
+
+@pytest.mark.parametrize(
+    ("layer", "other"),
+    [
+        (ForwardLayer(input_size=1, output_size=1), None),
+    ],
+    ids=["ForwardLayer vs. None"],
+)
+def test_should_return_not_implemented_if_other_is_not_forward_layer(layer: ForwardLayer, other: Any) -> None:
+    assert (layer.__eq__(other)) is NotImplemented
+
+
+@pytest.mark.parametrize(
+    ("layer1", "layer2"),
+    [
+        (
+            ForwardLayer(input_size=1, output_size=2),
+            ForwardLayer(input_size=1, output_size=2),
+        ),
+    ],
+    ids=["equal"],
+)
+def test_should_assert_that_equal_forward_layers_have_equal_hash(layer1: ForwardLayer, layer2: ForwardLayer) -> None:
+    assert layer1.__hash__() == layer2.__hash__()
+
+
+@pytest.mark.parametrize(
+    ("layer1", "layer2"),
+    [
+        (
+            ForwardLayer(input_size=1, output_size=2),
+            ForwardLayer(input_size=2, output_size=1),
+        ),
+    ],
+    ids=["not equal"],
+)
+def test_should_assert_that_different_forward_layers_have_different_hash(
+    layer1: ForwardLayer,
+    layer2: ForwardLayer,
+) -> None:
+    assert layer1.__hash__() != layer2.__hash__()
+
+
+@pytest.mark.parametrize(
+    "layer",
+    [
+        ForwardLayer(input_size=1, output_size=1),
+    ],
+    ids=["one"],
+)
+def test_should_assert_that_layer_size_is_greater_than_normal_object(layer: ForwardLayer) -> None:
+    assert sys.getsizeof(layer) > sys.getsizeof(object())