Mockito - Mocking a method with parameters

Question

I am writing unit tests for a method that takes in argument id which is something like below :

 public void searchid(String id) {
    Document doc = Repository.findDocument(id); //returns a document
    if (doc == null) {
      System.out.println("id missing");
    } else {
      String stringRecord = doc.asJsonString(); //converting doc to string

Here Repository.findDocument(id) is returning a document. In my unit test, I am getting the JSON file from src/test/resources. So, how do I mock Repository.findDocument(id), so as to fetch the file from my resource instead ?

Thanks,

A similiar question was answered here: https://stackoverflow.com/questions/21105403/mocking-static-methods-with-mockito. — canihazurcode, Sep 13 '17 at 11:15
Do you use `@Autowire Repository repository` in your unit test? — canihazurcode, Sep 13 '17 at 11:23

Venkat · Answer 1 · 2017-09-13T11:47:35.687

2

You can try to mock the Repository.findDocument(id) call in your unit test method.

Mockito.when(Repository.findDocument(Mockito.isA(String.class))).thenReturn(Mockito.mock(Document.class));

This will return Mocked Document object whenever the Repository.findDocument(id) call is made.

edited Sep 13 '17 at 11:47

answered Sep 13 '17 at 11:25

Venkat

56
4

So, I should parse the JSON file and store the ID and pass it in the above function ryt ? – AYa Sep 13 '17 at 11:41
Sorry didn't notice that you need Document object, I have edited my answer. If you wish to mock Document object with custom data you could do it. – Venkat Sep 13 '17 at 11:49
And where should I call my method `searchid(id)` ? – AYa Sep 13 '17 at 11:50
Both the mocking code and `searchid(id)` should be in your unit test method – Venkat Sep 13 '17 at 11:55
Hey, how can I mock Document object with custom data ? Sorry to ask but I am a newbie to this. – AYa Sep 13 '17 at 12:15

score 1 · Accepted Answer · answered Sep 18 '17 at 15:38

The key to testability is that you have a field repository that gets constructor-injected into your class. This way you can easily substitute the real repository by a fake instance (e.g a mockito mock).

The best source for learning how to write testable code, that I know, is http://misko.hevery.com/code-reviewers-guide/

Mockito - Mocking a method with parameters

2 Answers2