Add missing recursion detection test (#1030)

aws/sdk/integration-tests/s3/tests/recursion-detection.rs

+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
+
+use aws_sdk_s3::{Credentials, Region};
+use aws_smithy_client::test_connection::capture_request;
+use http::HeaderValue;
+
+#[tokio::test]
+async fn recursion_detection_applied() {
+    std::env::set_var("AWS_LAMBDA_FUNCTION_NAME", "some-function");
+    std::env::set_var("_X_AMZ_TRACE_ID", "traceid");
+    let (conn, captured_request) = capture_request(None);
+
+    let creds = Credentials::new(
+        "ANOTREAL",
+        "notrealrnrELgWzOk3IfjzDKtFBhDby",
+        Some("notarealsessiontoken".to_string()),
+        None,
+        "test",
+    );
+    let conf = aws_sdk_s3::Config::builder()
+        .credentials_provider(creds)
+        .region(Region::new("us-east-1"))
+        .build();
+    let client = aws_sdk_s3::Client::from_conf_conn(conf, conn);
+    let _response = client.list_objects_v2().bucket("test-bucket").send().await;
+    assert_eq!(
+        captured_request
+            .expect_request()
+            .headers()
+            .get("x-amzn-trace-id"),
+        Some(&HeaderValue::from_static("traceid"))
+    );
+}