diff --git a/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/TestUtils.java b/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/TestUtils.java
index 2c3842a3e3..5b22e1c5d9 100644
--- a/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/TestUtils.java
+++ b/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/TestUtils.java
@@ -22,14 +22,21 @@ import org.testng.Assert;
 import java.io.File;
 import java.net.URL;
 
+/**
+ * Utils class which provides utility methods for other testcases.
+ */
 public class TestUtils {
-
     static final String IOT_CORE_HOST = "iot.core.wso2.com";
     static final String IOT_CORE_HTTPS_PORT = "9443";
     static final String IOT_KEYMANAGER_HOST = "iot.keymanager.wso2.com";
     static final String IOT_KEYMANAGER_PORT = "9443";
     static final String CONTENT_TYPE = "application/json";
 
+    private static final String IOT_HOST_PROPERTY = "iot.core.host";
+    private static final String IOT_PORT_PROPERTY = "iot.core.https.port";
+    private static final String IOT_KEY_MANAGER_HOST_PROPERTY = "iot.keymanager.host";
+    private static final String IOT_KEY_MANAGER_PORT_PROPERTY = "iot.keymanager.https.port";
+
     static String getAbsolutePathOfConfig(String configFilePath) {
         ClassLoader classLoader = TestUtils.class.getClassLoader();
         URL invalidConfig = classLoader.getResource(configFilePath);
@@ -39,16 +46,16 @@ public class TestUtils {
     }
 
     static void setSystemProperties() {
-        System.setProperty("iot.core.host", IOT_CORE_HOST);
-        System.setProperty("iot.core.https.port", IOT_CORE_HTTPS_PORT);
-        System.setProperty("iot.keymanager.host", IOT_KEYMANAGER_HOST);
-        System.setProperty("iot.keymanager.https.port", IOT_KEYMANAGER_PORT);
+        System.setProperty(IOT_HOST_PROPERTY, IOT_CORE_HOST);
+        System.setProperty(IOT_PORT_PROPERTY, IOT_CORE_HTTPS_PORT);
+        System.setProperty(IOT_KEY_MANAGER_HOST_PROPERTY, IOT_KEYMANAGER_HOST);
+        System.setProperty(IOT_KEY_MANAGER_PORT_PROPERTY, IOT_KEYMANAGER_PORT);
     }
 
     static void resetSystemProperties() {
-        System.clearProperty("iot.core.host");
-        System.clearProperty("iot.core.https.port");
-        System.clearProperty("iot.keymanager.host");
-        System.clearProperty("iot.keymanager.https.port");
+        System.clearProperty(IOT_HOST_PROPERTY);
+        System.clearProperty(IOT_PORT_PROPERTY);
+        System.clearProperty(IOT_KEY_MANAGER_HOST_PROPERTY);
+        System.clearProperty(IOT_KEY_MANAGER_PORT_PROPERTY);
     }
 }
diff --git a/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/mock/MockClient.java b/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/mock/MockClient.java
index 3c5a8123ed..6c36969026 100644
--- a/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/mock/MockClient.java
+++ b/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/mock/MockClient.java
@@ -29,6 +29,9 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Mock implementation for CloseableHttpClient to be used in test cases.
+ */
 public class MockClient extends CloseableHttpClient {
     private List<CloseableHttpResponse> responses = new ArrayList<>();
     private int responseCount = 0;
@@ -36,8 +39,12 @@ public class MockClient extends CloseableHttpClient {
     @Override
     protected CloseableHttpResponse doExecute(HttpHost httpHost, HttpRequest httpRequest, HttpContext httpContext)
             throws IOException {
-        this.responseCount++;
-        return this.responses.get(this.responseCount - 1);
+        if (this.responseCount < this.responses.size()) {
+            this.responseCount++;
+            return this.responses.get(this.responseCount - 1);
+        } else {
+            return new MockHttpResponse();
+        }
     }
 
     @Override
diff --git a/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/mock/MockHttpResponse.java b/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/mock/MockHttpResponse.java
index 3eb070c18e..adfd7652c5 100644
--- a/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/mock/MockHttpResponse.java
+++ b/components/apimgt-extensions/org.wso2.carbon.apimgt.handlers/src/test/java/org/wso2/carbon/apimgt/handlers/mock/MockHttpResponse.java
@@ -28,6 +28,10 @@ import org.apache.http.params.HttpParams;
 import java.io.IOException;
 import java.util.Locale;
 
+/**
+ * Mock http response to be used in the test cases.
+ *
+ */
 public class MockHttpResponse implements CloseableHttpResponse {
     private HttpEntity httpEntity;
     private StatusLine statusLine;