diff --git a/.github/workflows/third-party-tests.yml b/.github/workflows/third-party-tests.yml
index 3fb9ac8..928c3f3 100644
--- a/.github/workflows/third-party-tests.yml
+++ b/.github/workflows/third-party-tests.yml
@@ -21,6 +21,7 @@ jobs:
           - 'mezzio'
           - 'spiral'
           - 'symfony_polyfill'
+          - 'composer'
 
     steps:
       - name: checkout
diff --git a/tests/third_party_tests.rs b/tests/third_party_tests.rs
index 4bf9154..8b0f5e9 100644
--- a/tests/third_party_tests.rs
+++ b/tests/third_party_tests.rs
@@ -113,6 +113,17 @@ fn third_party_8_symfony_polyfill() {
     );
 }
 
+#[test]
+fn third_party_9_composer() {
+    test_repository(
+        "composer",
+        "https://github.com/composer/composer",
+        "main",
+        &["src", "tests"],
+        &[]
+    );
+}
+
 fn test_repository(
     name: &str,
     repository: &str,