• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Paul Clapham
  • Ron McLeod
  • Bear Bibeault
  • Liutauras Vilda
Sheriffs:
  • Jeanne Boyarsky
  • Junilu Lacar
  • Henry Wong
Saloon Keepers:
  • Tim Moores
  • Stephan van Hulst
  • Jj Roberts
  • Tim Holloway
  • Piet Souris
Bartenders:
  • Himai Minh
  • Carey Brown
  • salvin francis

Powermock - null is returned

 
Greenhorn
Posts: 4
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hello,

I need your help with the following issue related with Junit testing:


I have the following class under test:



and the following unit test



when I uncomment the  "assertEquals("res",ExceptionUtil.stackToString(throwMock));" code I'm getting a null object returned.

java.lang.AssertionError: expected:<res> but was:<null>
at org.junit.Assert.fail(Assert.java:88)
at org.junit.Assert.failNotEquals(Assert.java:834)
at org.junit.Assert.assertEquals(Assert.java:118)
at org.junit.Assert.assertEquals(Assert.java:144)
at com.vw.client.test.ExceptionUtilTest.test(ExceptionUtilTest.java:44)



I've tried to debug the method under test with Junit but without any success.

What I'm doing wrong?

Regards,

 
Sheriff
Posts: 15989
265
Mac Android IntelliJ IDE Eclipse IDE Spring Debian Java Ubuntu Linux
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I'm confused... what are you trying to test here?  Because line 31 mocks all the static methods of the ExceptionUtil class and yet the rest of the test code appears to be wanting to test the static stackToString() method.

You don't mock code that you're actually trying to test. You only mock the dependencies that you want to control the behavior of. The Throwable object that the stackToString() method is collaborating with can be mocked but not the method under test itself.

This is the problem with mocks, especially when you're just starting out with unit testing. Beginners often get confused and end up testing mocks themselves instead of the production code.

The PowerMock README wrote:Please note that PowerMock is mainly intended for people with expert knowledge in unit testing. Putting it in the hands of junior developers may cause more harm than good.


If you're just trying to learn how to unit test, I suggest you start out by NOT using mock objects.
 
reply
    Bookmark Topic Watch Topic
  • New Topic