diff --git a/docker-compose.yml b/docker-compose.yml
index 3d0ff62cd5..eddc4a5670 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -110,6 +110,8 @@ services:
       PHP_FPM_GID: ${PHP_FPM_GID-1000}
       TRAVIS_BRANCH: ${TRAVIS_BRANCH-false}
       TRAVIS_PULL_REQUEST: ${TRAVIS_PULL_REQUEST-false}
+      GITHUB_REF: ${GITHUB_REF-false}
+      GITHUB_EVENT_NAME: ${GITHUB_EVENT_NAME-false}
 
     volumes:
       - ./tools/local-env/phpunit-config.ini:/usr/local/etc/php/conf.d/phpunit-config.ini
diff --git a/tests/phpunit/includes/abstract-testcase.php b/tests/phpunit/includes/abstract-testcase.php
index bbc365f671..4bc966fdb7 100644
--- a/tests/phpunit/includes/abstract-testcase.php
+++ b/tests/phpunit/includes/abstract-testcase.php
@@ -193,14 +193,18 @@ abstract class WP_UnitTestCase_Base extends PHPUnit\Framework\TestCase {
 		$github_event_name = getenv( 'GITHUB_EVENT_NAME' );
 		$github_ref        = getenv( 'GITHUB_REF' );
 
-		if ( ( ! $travis_branch || ! $travis_pull_request ) && ! $github_event_name ) {
-			return;
-		}
+		if ( 'false' !== $github_event_name ) {
+			// We're on GitHub Actions.
+			$skipped = array( 'pull_request', 'pull_request_target' );
 
-		if ( ( 'master' !== $travis_branch || 'false' !== $travis_pull_request ) && empty( $github_event_name ) ) {
-			$this->markTestSkipped( 'For automated test runs, this test is only run on trunk/master' );
-		} elseif ( in_array( $github_event_name, array( 'pull_request', 'pull_request_target' ), true ) || 'refs/heads/master' !== $github_ref ) {
-			$this->markTestSkipped( 'For automated test runs, this test is only run on trunk/master' );
+			if ( in_array( $github_event_name, $skipped, true ) || 'refs/heads/master' !== $github_ref ) {
+				$this->markTestSkipped( 'For automated test runs, this test is only run on trunk/master - GitHub only' );
+			}
+		} elseif ( 'false' !== $travis_branch ) {
+			// We're on Travis CI.
+			if ( 'master' !== $travis_branch || 'false' !== $travis_pull_request ) {
+				$this->markTestSkipped( 'For automated test runs, this test is only run on trunk/master - Travis only' );
+			}
 		}
 	}