Extension: Implement basic extractor test

axum/src/extension.rs

@@ -182,3 +182,62 @@ where
         self.inner.call(req)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::routing::get;
+    use crate::test_helpers::TestClient;
+    use crate::Router;
+    use http::StatusCode;
+
+    #[derive(Clone)]
+    struct Foo(String);
+
+    #[derive(Clone)]
+    struct Bar(String);
+
+    #[crate::test]
+    async fn extension_extractor() {
+        async fn requires_foo(Extension(foo): Extension<Foo>) -> String {
+            foo.0
+        }
+
+        async fn optional_foo(extension: Option<Extension<Foo>>) -> String {
+            extension.map(|foo| foo.0 .0).unwrap_or("none".to_owned())
+        }
+
+        async fn requires_bar(Extension(bar): Extension<Bar>) -> String {
+            bar.0
+        }
+
+        async fn optional_bar(extension: Option<Extension<Bar>>) -> String {
+            extension.map(|bar| bar.0 .0).unwrap_or("none".to_owned())
+        }
+
+        let app = Router::new()
+            .route("/requires_foo", get(requires_foo))
+            .route("/optional_foo", get(optional_foo))
+            .route("/requires_bar", get(requires_bar))
+            .route("/optional_bar", get(optional_bar))
+            .layer(Extension(Foo("foo".to_owned())));
+
+        let client = TestClient::new(app);
+
+        let response = client.get("/requires_foo").await;
+        assert_eq!(response.status(), StatusCode::OK);
+        assert_eq!(response.text().await, "foo");
+
+        let response = client.get("/optional_foo").await;
+        assert_eq!(response.status(), StatusCode::OK);
+        assert_eq!(response.text().await, "foo");
+
+        let response = client.get("/requires_bar").await;
+        assert_eq!(response.status(), StatusCode::INTERNAL_SERVER_ERROR);
+        assert_eq!(response.text().await, "Missing request extension: Extension of type `axum::extension::tests::Bar` was not found. Perhaps you forgot to add it? See `axum::Extension`.");
+
+        let response = client.get("/optional_bar").await;
+        assert_eq!(response.status(), StatusCode::OK);
+        assert_eq!(response.text().await, "none");
+    }
+}