[#3176] Add readme

tests/README.md

@@ -0,0 +1,41 @@
+# WooCommerce Unit Tests
+
+## Initial Setup
+
+1) Install [PHPUnit](http://phpunit.de/) by following their [installation guide](https://phpunit.de/getting-started.html). If you've installed it correctly, this should display the version:
+
+    $ phpunit --version
+
+2) Install WordPress and the WP Unit Test lib using the `install-wp-tests.sh` script. Change to the plugin root directory and type:
+
+    $ tests/install-wp-tests.sh <db-name> <db-user> <db-password> [db-host]
+
+Sample usage:
+
+    $ tests/install-wp-tests.sh woocommerce_tests root root
+
+**Important**: The `<db-name>` database will be created if it doesn't exist and all data will be removed during testing.
+
+## Running Tests
+
+Simply change to the plugin root directory and type:
+
+    $ phpunit
+
+The tests will execute and you'll be presented with a summary. Code coverage documentation is automatically generated as HTML in the `tmp/coverage` directory.
+
+You can run specific tests by providing the path and filename to the test class:
+
+    $ phpunit tests/unit-tests/api/webhooks
+
+A text code coverage summary can be displayed using the `--coverage-text` option:
+
+    $ phpunit --coverage-text
+
+## Writing Tests
+
+TODO
+
+## Automated Tests
+
+Tests are automatically run with Travis-CI for each commit and pull request.