Junit testing with dependencies

[Pradeep Kumar]

Hi friends,
I am a beginner in Junit testing and just started exploring Junit for writing the test cases. I have a scenario where I am struck and finding it difficult to proceed. The scenario is that I am testing a public method which internally calls private methods. In on of the private method, the method tries to connect to the environment and the properties of the environment is fetched in the private method. How can i override the behavior such that I can override the behavior by populating the properties and mimic the environment dependency even though I do not directly call the private method.

Ex:

        @Test
        testcase(){
          //test a public method
          publicMethodToTest();
        }
       

In the main class:

      publicMethodToTest(){
        //call to private method
        privateMethodCall();
     }

     privateMethodCall(){
             String userName = ConfigDetail.getUserName();
             String password =  ConfigDetail.getPassword();

       //connect to the env and do the operation..
    }
    

In the ConfigDetail class

    public static ConfigDetail getInstance(){
     if (configDetail == null){ return new ConfigDetail();
     }
      return configDetail;
    }
    //properties are set at loading time
     public String getUserName(){}
     public String  getPassword(){}
     public void setUserName(){}
     public void getUserName(){}
    

Please let me know to do proceed.
Thanks and Regards,
Pradeep

[Jeanne Boyarsky]

Pradeep,
You are going to need to refactor that code to make it testable. Ideas:

1) Pass in ConfigDetails so you can make your own - only works if you want to integration test thru to the database

2) Move the private method code to an other class with an interface and mock it out

3) Make the private method default access or protected and override it to do nothing.

#3 is often a hack, but it is easiest to do. Especially if you can't change the code much.

[Pradeep Kumar]

Jeanne Boyarsky wrote:Pradeep,
You are going to need to refactor that code to make it testable. Ideas:

3) Make the private method default access or protected and override it to do nothing.

#3 is often a hack, but it is easiest to do. Especially if you can't change the code much.

I like the idea of the 3rd option. How do i override the method and test the method. Do you mean extends the class and override the method and test the sub class?

[Jeanne Boyarsky]

Pradeep Kumar wrote:

Jeanne Boyarsky wrote:

3) Make the private method default access or protected and override it to do nothing.

#3 is often a hack, but it is easiest to do. Especially if you can't change the code much.

I like the idea of the 3rd option. How do i override the method and test the method. Do you mean extends the class and override the method and test the sub class?

Exactly!

public class ComplexCode {
 public void a() {
   b();
 }
 void b() {
    // environment stuff that can't be moved goes here
 }
}
public class MockComplexCode {
  void b() {
    // no operation
  }
}