code: def test_linear(self):
      x = np.random.random((10, 5))
      self.assertAllClose(x, activations.linear(x))
  
      # Test with 1D array
      x_1d = np.random.uniform(-10, 10, 5)
      self.assertAllClose(x_1d, activations.linear(x_1d))
  
      # Test with 2D array
      x = np.random.uniform(-10, 10, (10, 5))
      self.assertAllClose(x, activations.linear(x))
  
      # Test with 3D array
      x_3d = np.random.uniform(-10, 10, (5, 5, 5))
      self.assertAllClose(x_3d, activations.linear(x_3d))
  
      # Test with float32 data type
      x_float32 = np.random.uniform(-10, 10, (10, 5)).astype(np.float32)
      self.assertAllClose(x_float32, activations.linear(x_float32))
      # Test with int32 data type
      x_int32 = np.random.randint(-10, 10, (10, 5)).astype(np.int32)
      self.assertAllClose(x_int32, activations.linear(x_int32))
  
imports: import numpy
  from keras import activations
  from keras import backend
  from keras import testing
label_desc: Use image node_id 38 for calling the ActivationsTest obj's underlying member method code with example usage: obj.test_linear() without return types