From fb097d52032cc8dd379c9a80fecfdf90a56f3872 Mon Sep 17 00:00:00 2001
From: Peter Nied <petern@amazon.com>
Date: Wed, 15 Nov 2023 20:34:36 +0000
Subject: [PATCH] Validate content type of responses

Signed-off-by: Peter Nied <petern@amazon.com>
---
 .../framework/cluster/TestRestClient.java     | 25 ++++++++++++++++
 .../security/test/helper/rest/RestHelper.java | 29 +++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/src/integrationTest/java/org/opensearch/test/framework/cluster/TestRestClient.java b/src/integrationTest/java/org/opensearch/test/framework/cluster/TestRestClient.java
index e38ef949cb..fa5570e9f2 100644
--- a/src/integrationTest/java/org/opensearch/test/framework/cluster/TestRestClient.java
+++ b/src/integrationTest/java/org/opensearch/test/framework/cluster/TestRestClient.java
@@ -65,6 +65,7 @@
 import org.apache.hc.core5.http.io.entity.StringEntity;
 import org.apache.hc.core5.http.message.BasicHeader;
 import org.apache.hc.core5.net.URIBuilder;
+import org.apache.http.HttpHeaders;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -76,7 +77,9 @@
 import static java.lang.String.format;
 import static java.util.Objects.requireNonNull;
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.emptyOrNullString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.notNullValue;
 
 /**
@@ -284,7 +287,29 @@ public HttpResponse(CloseableHttpResponse inner) throws IllegalStateException, I
             this.header = inner.getHeaders();
             this.statusCode = inner.getCode();
             this.statusReason = inner.getReasonPhrase();
+
             inner.close();
+
+            if (this.body.length() != 0) {
+                verifyContentType();
+            }
+        }
+
+        private void verifyContentType() {
+            final String contentType = this.getHeader(HttpHeaders.CONTENT_TYPE).getValue();
+            if (contentType.equals("application/json")) {
+                assertThat("Response body should not have been empty", body, emptyOrNullString());
+                assertThat("Response body format was not json, body: " + body, body.charAt(0), equalTo("{"));
+            } else {
+                if (body.length() != 0) {
+                    assertThat(
+                        "Response body format was json, whereas content-type was " + contentType + ", body: " + body,
+                        body.charAt(0),
+                        not(equalTo("{"))
+                    );
+                }
+            }
+
         }
 
         public String getContentType() {
diff --git a/src/test/java/org/opensearch/security/test/helper/rest/RestHelper.java b/src/test/java/org/opensearch/security/test/helper/rest/RestHelper.java
index 43e7afc559..b9fd2b1a19 100644
--- a/src/test/java/org/opensearch/security/test/helper/rest/RestHelper.java
+++ b/src/test/java/org/opensearch/security/test/helper/rest/RestHelper.java
@@ -90,6 +90,11 @@
 import org.opensearch.security.test.helper.cluster.ClusterInfo;
 import org.opensearch.security.test.helper.file.FileHelper;
 
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.emptyOrNullString;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.not;
+
 public class RestHelper {
 
     protected final Logger log = LogManager.getLogger(RestHelper.class);
@@ -402,6 +407,30 @@ public HttpResponse(SimpleHttpResponse inner) throws IllegalStateException, IOEx
             this.statusCode = inner.getCode();
             this.statusReason = inner.getReasonPhrase();
             this.protocolVersion = inner.getVersion();
+
+            if (this.body.length() != 0) {
+                verifyBodyContentType();
+            }
+        }
+
+        private void verifyBodyContentType() {
+            final String contentType = this.getHeaders()
+                .stream()
+                .filter(h -> h.getName() == HttpHeaders.CONTENT_TYPE)
+                .map(Header::getValue)
+                .findFirst()
+                .orElseThrow(() -> new RuntimeException("No content type found"));
+
+            if (contentType.equals("application/json")) {
+                assertThat("Response body should not have been empty", body, emptyOrNullString());
+                assertThat("Response body format was not json, body: " + body, body.charAt(0), equalTo("{"));
+            } else {
+                assertThat(
+                    "Response body format was json, whereas content-type was " + contentType + ", body: " + body,
+                    body.charAt(0),
+                    not(equalTo("{"))
+                );
+            }
         }
 
         public String getContentType() {