docs: add docs for running tests locally (#538)

Signed-off-by: Michael Rebello <[email protected]>
Signed-off-by: JP Simard <[email protected]>

mobile/docs/root/development/development.rst

@@ -10,4 +10,5 @@ developing Envoy Mobile.
   :maxdepth: 2
 
   performance/performance
+  testing/testing
   tools/tools

mobile/docs/root/development/testing/testing.rst

@@ -0,0 +1,40 @@
+.. _testing:
+
+Testing
+=======
+
+Envoy Mobile strives to have a high standard of code quality and test coverage for the entire
+project.
+
+All unit tests are in the various ``library/<language>`` directories of the repository,
+and are run on CI for all PRs and merges to master.
+
+Tests may be run locally as outlined below.
+
+.. note::
+
+  The overall project testing strategy is being revisited as part of :issue:`#197 <197>`.
+
+----------
+Java tests
+----------
+
+To run the entire Java unit test suite locally, use the following Bazel command:
+
+``./bazelw test --test_output=all --build_tests_only //library/java/test/...``
+
+------------
+Kotlin tests
+------------
+
+To run the entire Kotlin unit test suite locally, use the following Bazel command:
+
+``./bazelw test --test_output=all --build_tests_only //library/kotlin/test/...``
+
+-----------
+Swift tests
+-----------
+
+To run the entire Swift unit test suite locally, use the following Bazel command:
+
+``./bazelw test --test_output=all --build_tests_only //library/swift/test/...``