Document the quality assurance plan for PRs (#1649)

---------

Co-authored-by: Julian Miller <[email protected]>
Co-authored-by: Matthew Michel <[email protected]>

CONTRIBUTING.md

@@ -5,6 +5,12 @@ We welcome community contributions to oneAPI DPC++ Library (oneDPL). You can:
 - Submit your changes directly with a [pull request](https://github.com/oneapi-src/oneDPL/pulls).
 - Log a bug or feedback with an [issue](https://github.com/oneapi-src/oneDPL/issues).
 
+# License
+
+oneDPL is licensed under the terms in [LICENSE](https://github.com/oneapi-src/oneDPL/blob/release_oneDPL/licensing/LICENSE.txt).
+By contributing to the project, you agree to the license and copyright terms therein and
+release your contribution under these terms.
+
 # Pull Requests
 
 This project follows the
@@ -13,6 +19,8 @@ your change directly to the repository:
 
 - Make sure your code is in line with our
   [coding conventions](#coding-conventions).
+- Test your code locally to identify and resolve simple issues by doing
+  [validation testing](#validation-testing).
 - Submit a
   [pull request](https://docs.github.com/en/free-pro-team@latest/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request) into the
   main branch. You may add a description of your contribution into [CREDITS.txt](https://github.com/oneapi-src/oneDPL/blob/main/CREDITS.txt).
@@ -21,9 +29,39 @@ your change directly to the repository:
 
 Running clang-format is required, except in the [test folder](https://github.com/oneapi-src/oneDPL/tree/main/test).
 
-# License
+# Validation Testing
 
-oneDPL is licensed under the terms in [LICENSE](https://github.com/oneapi-src/oneDPL/blob/release_oneDPL/licensing/LICENSE.txt).
-By contributing to the project, you agree to the license and copyright terms therein and
-release your contribution under these terms.
+The oneDPL test suite is organized in the test directory by the area of code tested.
+* `general` - Basic tests of oneDPL policies and SYCL functionality needed
+* `general/sycl_iterator` - Tests of oneDPL algorithms on SYCL buffers
+* `kt` - Tests of the oneDPL experimental kernel template algorithms that require specific hardware support
+* `parallel_api` - Tests of oneDPL Parallel Algorithms
+* `pstl_offload` - Tests of support for offload using standard execution policies
+* `xpu_api` - Tests of the use of C++ standard APIs in SYCL kernels
+
+oneDPL validation tests can be configured through CMake to run on different devices including CPU and GPU by specifying the oneDPL backend to use and
+the device type to be used if the DPC++ backend is being tested. The oneTBB and OpenMP backends for oneDPL can be used when the device type is CPU or HOST.
+
+To run oneDPL validation tests with the oneDPL build system you will need CMake and CTest installed. The following example shows how to build and run tests
+using the GPU on your local system using the Intel® oneAPI DPC++ Compiler.
+
+1. Configure the build files by running the following command that creates a build directory named `build_gpu_tests`.
+```
+cmake -DCMAKE_CXX_COMPILER=icpx -DCMAKE_CXX_STANDARD=17 -DONEDPL_BACKEND=dpcpp -DONEDPL_DEVICE_TYPE=gpu -DCMAKE_BUILD_TYPE=release -B build_gpu_tests
+```
+
+2. Build the tests
+```
+cmake --build build_gpu_tests --target build-onedpl-tests # specify a specific test name (e.g., reduce.pass) to build a single test
+```
+
+3. Run the tests from the `build_gpu_tests` directory
+```
+ctest --output-on-failure --timeout 1200 -R ^reduce.pass$ # Add -R testname (e.g., -R ^reduce.pass$) to run just one test.
+```
+
+Before submitting a PR to the oneDPL repository please run the tests that exercise the code you have updated. If you need help identifying those tests please
+check with the maintainers on [UXL Foundation Slack](https://slack-invite.uxlfoundation.org/) using the [#onedpl](https://uxlfoundation.slack.com/channels/onedpl) channel
+or ask a question through [GitHub issues](https://github.com/oneapi-src/oneDPL/issues).
 
+For more details on configurations available for oneDPL testing see the [CMake README](https://github.com/oneapi-src/oneDPL/blob/main/cmake/README.md).