groupnormalization with groups1 will become instancenormalization groupnormalization with groups 1 will become instancenormalization
import numpy as np
import pytest

from keras import constraints
from keras import layers
from keras import regularizers
from keras import testing


class GroupNormalizationTest(testing.TestCase):
    @pytest.mark.requires_trainable_backend
    def test_groupnorm(self):
        self.run_layer_test(
            layers.GroupNormalization,
            init_kwargs={
                "gamma_regularizer": regularizers.L2(0.01),
                "beta_regularizer": regularizers.L2(0.01),
            },
            input_shape=(3, 4, 32),
            expected_output_shape=(3, 4, 32),
            expected_num_trainable_weights=2,
            expected_num_non_trainable_weights=0,
            expected_num_seed_generators=0,
            expected_num_losses=2,
            supports_masking=True,
        )

        self.run_layer_test(
            layers.GroupNormalization,
            init_kwargs={
                "groups": 4,
                "gamma_constraint": constraints.UnitNorm(),
                "beta_constraint": constraints.UnitNorm(),
            },
            input_shape=(3, 4, 4),
            expected_output_shape=(3, 4, 4),
            expected_num_trainable_weights=2,
            expected_num_non_trainable_weights=0,
            expected_num_seed_generators=0,
            expected_num_losses=0,
            supports_masking=True,
        )

    def test_undefined_dim_error(self):
        inputs = layers.Input(shape=(2, 2, 2, None))
        layer = layers.GroupNormalization()
        with self.assertRaisesRegex(
            ValueError,
            (
                "input tensor should have a defined dimension but the layer "
                "received an input with shape"
            ),
        ):
            _ = layer(inputs)

    def test_groups_bigger_than_dim_error(self):
        inputs = np.ones(shape=(2, 2, 2, 4))
        layer = layers.GroupNormalization(groups=5)
        with self.assertRaisesRegex(
            ValueError,
            "cannot be more than the number of channels",
        ):
            _ = layer(inputs)

    def test_groups_not_a_multiple_of_dim_error(self):
        inputs = np.ones(shape=(2, 2, 2, 4))
        layer = layers.GroupNormalization(groups=3)
        with self.assertRaisesRegex(
            ValueError,
            "must be a multiple of the number of channels",
        ):
            _ = layer(inputs)

    def test_groups_instance_norm(self):
        
        instance_norm_layer_1 = layers.GroupNormalization(
            groups=-1, axis=-1, scale=False, center=False
        )
        instance_norm_layer_2 = layers.GroupNormalization(
            groups=4, axis=-1, scale=False, center=False
        )
        inputs = np.array([[[-1.0, 1.0, 0, 2.0], [1.0, 3.0, -4, -2.0]]])

        outputs_1 = instance_norm_layer_1(inputs)
        outputs_2 = instance_norm_layer_2(inputs)

        self.assertAllClose(outputs_1, outputs_2)

    def test_correctness_instance_norm(self):
        instance_norm_layer = layers.GroupNormalization(
            groups=4, axis=-1, scale=False, center=False
        )

        inputs = np.array([[[-1.0, 1.0, 0, 2.0], [1.0, 3.0, -4, -2.0]]])

        expected_instance_norm_output = np.array(
            [[[-1.0, -1.0, 1.0, 1.0], [1.0, 1.0, -1.0, -1.0]]]
        )

        self.assertAllClose(
            instance_norm_layer(inputs),
            expected_instance_norm_output,
            atol=1e-3,
        )

    def test_correctness_1d(self):
        layer_with_1_group = layers.GroupNormalization(
            groups=1, axis=-1, scale=False, center=False
        )
        layer_with_2_groups = layers.GroupNormalization(
            groups=2, axis=1, scale=False, center=False
        )

        inputs = np.array([[-1.0, -1.0, 1.0, 1.0, 2.0, 2.0, 0, -2.0]])

        expected_output_1_group = np.array(
            [[-0.898, -0.898, 0.539, 0.539, 1.257, 1.257, -0.180, -1.616]],
        )
        self.assertAllClose(
            layer_with_1_group(inputs),
            expected_output_1_group,
            atol=1e-3,
        )

        expected_output_2_groups = np.array(
            [[-1.0, -1.0, 1.0, 1.0, 0.904, 0.904, -0.301, -1.507]]
        )
        self.assertAllClose(
            layer_with_2_groups(inputs),
            expected_output_2_groups,
            atol=1e-3,
        )

    def test_correctness_2d(self):
        layer_with_1_group = layers.GroupNormalization(
            groups=1, axis=-1, scale=False, center=False
        )
        layer_with_2_groups = layers.GroupNormalization(
            groups=2, axis=2, scale=False, center=False
        )

        inputs = np.array([[[-1.0, -1.0, 2.0, 2.0], [1.0, 1.0, 0, -2.0]]])

        expected_output_1_group = np.array(
            [[[-0.898, -0.898, 1.257, 1.257], [0.539, 0.539, -0.180, -1.616]]]
        )

        self.assertAllClose(
            layer_with_1_group(inputs),
            expected_output_1_group,
            atol=1e-3,
        )

        expected_output_2_groups = np.array(
            [[[-1.0, -1.0, 0.904, 0.904], [1.0, 1.0, -0.301, -1.507]]]
        )
        self.assertAllClose(
            layer_with_2_groups(inputs),
            expected_output_2_groups,
            atol=1e-3,
        )

    def test_broadcasting_2d_channels_first(self):
        x = np.arange(16).reshape((1, 4, 2, 2)).astype("float32")
        x = layers.GroupNormalization(groups=2, axis=1)(x)
        self.assertAllClose(
            x,
            np.array(
                [
                    [
                        [[-1.5274, -1.0910], [-0.6546, -0.2182]],
                        [[0.2182, 0.6546], [1.0910, 1.5274]],
                        [[-1.5274, -1.0910], [-0.6546, -0.2182]],
                        [[0.2182, 0.6546], [1.0910, 1.5274]],
                    ]
                ]
            ),
            atol=1e-3,
        )