class_docstr: Tests of GraphAttention layer
class_docstr_tok: ["Tests","of","GraphAttention","layer"]
code: def test_constructor(self):
      # attn_heads_reduction = "concat":
      layer = self.layer(
          units=self.F_out,
          attn_heads=self.attn_heads,
          attn_heads_reduction="concat",
          activation=self.activation,
      )
      assert layer.units == self.F_out
      assert layer.attn_heads == self.attn_heads
      assert layer.output_dim == self.F_out * self.attn_heads
      assert layer.activation == keras.activations.get(self.activation)
  
      # attn_heads_reduction = "average":
      layer = self.layer(
          units=self.F_out,
          attn_heads=self.attn_heads,
          attn_heads_reduction="average",
          activation=self.activation,
      )
      assert layer.output_dim == self.F_out
  
      # attn_heads_reduction = "ave":
      with pytest.raises(ValueError):
          self.layer(
              units=self.F_out,
              attn_heads=self.attn_heads,
              attn_heads_reduction="ave",
              activation=self.activation,
          )
  
imports: import pytest
  import scipy.sparse
  import tensorflow
  from tensorflow import keras
  from tensorflow.keras import backend
  from tensorflow.keras.layers import Input
  from stellargraph.mapper import FullBatchNodeGenerator, FullBatchLinkGenerator, GraphSAGENodeGenerator
  from stellargraph.layer import *
  from ..test_utils.graphs import example_graph
  from ..None import test_utils
label_desc: Use image node_id 3 for calling the Test_GraphAttention obj's underlying member method code with example usage: obj.test_constructor() without return types