class_docstr: Tests :class:`~texar.tf.modules.decoders.rnn_decoders.BasicRNNDecoder`.
      
code: def test_output_layer(self):
      decoder = BasicRNNDecoder(
          vocab_size=self._vocab_size, output_layer=None
      )
      self.assertIsInstance(decoder, BasicRNNDecoder)
  
      decoder = BasicRNNDecoder(output_layer=tf.identity)
      self.assertIsInstance(decoder, BasicRNNDecoder)
  
      tensor = tf.random_uniform(
          [self._emb_dim, self._vocab_size], maxval=1, dtype=tf.float32
      )
      decoder = BasicRNNDecoder(output_layer=tensor)
      self.assertIsInstance(decoder, BasicRNNDecoder)
      self.assertEqual(decoder.vocab_size, self._vocab_size)
  
imports: import numpy
  import tensorflow
  from texar.tf.modules.decoders.rnn_decoders import BasicRNNDecoderOutput
  from texar.tf.modules.decoders.rnn_decoders import BasicRNNDecoder
  from texar.tf.modules.decoders.rnn_decoders import AttentionRNNDecoderOutput
  from texar.tf.modules.decoders.rnn_decoders import AttentionRNNDecoder
  from texar.tf.modules.decoders.rnn_decoder_helpers import get_helper
  from texar.tf import context
label_desc: Use image node_id 3 for calling the BasicRNNDecoderTest obj's underlying member method code with example usage: obj.test_output_layer() without return types