Mock System class to get system properties

java mocking environment-variables system powermock
sailaja.vellanki picture sailaja.vellanki · Dec 5, 2013 · Viewed 38k times · Source

I have a folder path set in system variable through JVM arguments in Eclipse and I am trying to access it in my class as: System.getProperty("my_files_path").

While writing junit test method for this class, I tried mocking this call as test classes do not consider JVM arguments. I have used PowerMockito to mock static System class and tried returning some path when System.getProperpty is being called.

Had @RunWith(PowerMockRunner.class) and @PrepareForTest(System.class) annotations at class level. However, System class is not getting mocked as a result I always get null result. Any help is appreciated.

Answer

sailaja.vellanki picture sailaja.vellanki · Dec 16, 2013

Thanks Satish. This works except with a small modification. I wrote PrepareForTest(PathFinder.class), preparing the class I am testing for test cases instead of System.class

Also, as mock works only once, I called my method right after mocking. My code just for reference:

@RunWith(PowerMockRunner.class)
@PrepareForTest(PathInformation.class)
public class PathInformationTest {

    private PathFinder pathFinder = new PathFinder();

@Test
    public void testValidHTMLFilePath() { 
        PowerMockito.mockStatic(System.class);
        PowerMockito.when(System.getProperty("my_files_path")).thenReturn("abc");
        assertEquals("abc",pathFinder.getHtmlFolderPath());
    }
}

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