docstr: Tests that supplying negative times in sample_paths is an error.
docstr_tok: ["Tests","that","supplying","negative","times","in","sample_paths","is","an","error","."]
code: def test_negative_times_is_error(self):
      """Tests that supplying negative times in sample_paths is an error."""
      process = BrownianMotion()
      with self.assertRaises(tf.errors.InvalidArgumentError):
          self.evaluate(
              process.sample_paths([-0.1, 0.09, 1.0], num_samples=1)
          )
  
file_path: tf-quant-finance/tf_quant_finance/models/legacy/brownian_motion_test.py
imports: import numpy
  import tensorflow.compat.v2
  from tensorflow.python.framework import test_util
  from tf_quant_finance.models.legacy.brownian_motion import BrownianMotion
label_desc: Use image node_id 9 for calling the BrownianMotionTest obj's underlying member method code with example usage: obj.test_negative_times_is_error() without return types