diff --git a/tests/phpunit/includes/spy-rest-server.php b/tests/phpunit/includes/spy-rest-server.php
index 24c12c5fcb..596117347c 100644
--- a/tests/phpunit/includes/spy-rest-server.php
+++ b/tests/phpunit/includes/spy-rest-server.php
@@ -8,7 +8,7 @@ class Spy_REST_Server extends WP_REST_Server {
 	public $override_by_default = false;
 
 	/**
-	 * Get the raw $endpoints data from the server
+	 * Gets the raw $endpoints data from the server.
 	 *
 	 * @return array
 	 */
@@ -17,28 +17,39 @@ class Spy_REST_Server extends WP_REST_Server {
 	}
 
 	/**
-	 * Allow calling protected methods from tests
+	 * Allow calling protected methods from tests.
 	 *
-	 * @param string $method Method to call
-	 * @param array $args Arguments to pass to the method
+	 * @param string $method Method to call.
+	 * @param array  $args   Arguments to pass to the method.
 	 * @return mixed
 	 */
 	public function __call( $method, $args ) {
 		return call_user_func_array( array( $this, $method ), $args );
 	}
 
+	/**
+	 * Adds a header to the list of sent headers.
+	 *
+	 * @param string $header Header name.
+	 * @param string $value  Header value.
+	 */
 	public function send_header( $header, $value ) {
 		$this->sent_headers[ $header ] = $value;
 	}
 
+	/**
+	 * Removes a header from the list of sent headers.
+	 *
+	 * @param string $header Header name.
+	 */
 	public function remove_header( $header ) {
 		unset( $this->sent_headers[ $header ] );
 	}
 
 	/**
-	 * Override the dispatch method so we can get a handle on the request object.
+	 * Overrides the dispatch method so we can get a handle on the request object.
 	 *
-	 * @param  WP_REST_Request $request
+	 * @param  WP_REST_Request $request Request to attempt dispatching.
 	 * @return WP_REST_Response Response returned by the callback.
 	 */
 	public function dispatch( $request ) {
@@ -47,19 +58,26 @@ class Spy_REST_Server extends WP_REST_Server {
 	}
 
 	/**
-	 * Override the register_route method so we can re-register routes internally if needed.
+	 * Overrides the register_route method so we can re-register routes internally if needed.
 	 *
 	 * @param string $namespace  Namespace.
 	 * @param string $route      The REST route.
 	 * @param array  $route_args Route arguments.
 	 * @param bool   $override   Optional. Whether the route should be overridden if it already exists.
-	 *                           Default false. Also set $GLOBALS['wp_rest_server']->override_by_default = true
+	 *                           Default false. Also set `$GLOBALS['wp_rest_server']->override_by_default = true`
 	 *                           to set overrides when you don't have access to the caller context.
 	 */
 	public function register_route( $namespace, $route, $route_args, $override = false ) {
 		parent::register_route( $namespace, $route, $route_args, $override || $this->override_by_default );
 	}
 
+	/**
+	 * Serves the request and returns the result.
+	 *
+	 * @param string $path Optional. The request route. If not set, `$_SERVER['PATH_INFO']` will be used.
+	 *                     Default null.
+	 * @return null|false Null if not served and a HEAD request, false otherwise.
+	 */
 	public function serve_request( $path = null ) {
 
 		ob_start();