[Fix doc issue 6242] Add a tip about testng in function debug
Fix
@@ -37,6 +37,9 @@ public class JavaNativeExclamationFunction implements Function<String, String> {
You can write a simple unit test to test Pulsar Function.
+> #### Tip
+> Pulsar uses testng for testing.
+
```java
@Test
public void testJavaNativeExclamationFunction() {
@@ -62,6 +65,9 @@ public class ExclamationFunction implements Function<String, String> {
In this situation, you can write a unit test for this function as well. Remember to mock the `Context` parameter. The following is an example.
+> #### Tip
+> Pulsar uses testng for testing.
+
```java
@Test
public void testExclamationFunction() {
