message: Adding documentation for running doctests locally
diff: @@ -216,3 +216,41 @@ There are two ways to run TensorFlow unit tests.
  See
  [TensorFlow Builds](https://github.com/tensorflow/tensorflow/tree/master/tensorflow/tools/ci_build)
  for details.
  +
  +#### Running doctest for testable docstring
  +
  +There are two ways to test the code in the docstring locally:
  +
  +1. If you are only changing the docstring of a class/function/method, then you
  + can test it by passing that file's path to
  + [tf_doctest.py](https://www.tensorflow.org/code/tensorflow/tools/docs/tf_doctest.py).
  + For example:
  +
  + ```bash
  + python tf_doctest.py --file=<file_path>
  + ```
  +
  + This will run it using your installed version of TensorFlow. To be sure
  + you're running the same code that you're testing:
  +
  + * Use an up to date [tf-nightly](https://pypi.org/project/tf-nightly/)
  + `pip install -U tf-nightly`
  + * Rebase your pull request onto a recent pull from
  + [TensorFlow's](https://github.com/tensorflow/tensorflow) master branch.
  +
  +2. If you are changing the code and the docstring of a class/function/method,
  + then you will need to
  + [build TensorFlow from source](https://www.tensorflow.org/install/source).
  + Once you are setup to build from source, you can run the tests:
  +
  + ```bash
  + bazel run //tensorflow/tools/docs:tf_doctest
  + ```
  +
  + or
  +
  + ```bash
  + bazel run //tensorflow/tools/docs:tf_doctest -- --module=ops.array_ops
  + ```
  +
  + The `--module` is relative to `tensorflow.python`.
  