[ISSUE #4994] unit tests for HttpRequestUtil.java (#5037)

* test: adds unit tests for HttpRequestUtil.java

* fix: fixes checkstyle warnings

eventmesh-runtime/src/test/java/org/apache/eventmesh/runtime/util/HttpRequestUtilTest.java

@@ -0,0 +1,84 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.eventmesh.runtime.util;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import io.netty.buffer.Unpooled;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpVersion;
+
+public class HttpRequestUtilTest {
+
+    @Test
+    public void testShouldParseHttpGETRequestBody() throws IOException {
+        HttpRequest httpRequest = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, "/some-path?q1=xyz");
+        Map<String, Object> expected = new HashMap<>();
+        expected.put("q1", "xyz");
+        Assertions.assertEquals(expected, HttpRequestUtil.parseHttpRequestBody(httpRequest));
+    }
+
+    @Test
+    public void testShouldParseHttpPOSTRequestBody() throws IOException {
+        HttpRequest httpRequest = new DefaultFullHttpRequest(
+            HttpVersion.HTTP_1_1, HttpMethod.POST,
+            "/some-path",
+            Unpooled.copiedBuffer(("q1=xyz").getBytes())
+        );
+        Map<String, Object> expected = new HashMap<>();
+        expected.put("q1", "xyz");
+        Assertions.assertEquals(expected, HttpRequestUtil.parseHttpRequestBody(httpRequest));
+    }
+
+    @Test
+    public void testQueryStringToMap() {
+        Map<String, Object> expected = new HashMap<>();
+        expected.put("q1", "xyz");
+        expected.put("q2", "abc");
+        Assertions.assertEquals(expected, HttpRequestUtil.queryStringToMap("q1=xyz&q2=abc"));
+    }
+
+    @Test
+    public void testGetQueryParam() {
+        HttpRequest httpRequest = new DefaultFullHttpRequest(
+            HttpVersion.HTTP_1_1,
+            HttpMethod.GET,
+            "/some-path?q1=xyz"
+        );
+        Assertions.assertEquals("xyz", HttpRequestUtil.getQueryParam(httpRequest, "q1", ""));
+    }
+
+    @Test
+    public void testGetBodyParam() throws IOException {
+        HttpRequest httpRequest = new DefaultFullHttpRequest(
+            HttpVersion.HTTP_1_1,
+            HttpMethod.POST,
+            "/some-path",
+            Unpooled.copiedBuffer(("q1=xyz").getBytes())
+        );
+        Assertions.assertEquals("xyz", HttpRequestUtil.getBodyParam(httpRequest, "q1"));
+    }
+
+}