How to mock FileInputStream and other *Streams

Question

I have class that gets GenericFile as input argument reads data and does some additional processing. I need to test it:

public class RealCardParser {

    pu         


        

Answer 1

You can mock FileInputStream by using PowerMockRunner and PowerMockito. See the below code for mocking-

@RunWith(PowerMockRunner.class)
@PrepareForTest({
        FileInputStream.class
})
public class A{

 @Test
        public void testFileInputStream ()
                    throws Exception
       {
           final FileInputStream fileInputStreamMock = PowerMockito.mock(FileInputStream.class);
           PowerMockito.whenNew(FileInputStream.class).withArguments(Matchers.anyString())
                               .thenReturn(fileInputStreamMock);
    //Call the actual method containing the new constructor of FileInputStream 

        }
}