Mockito: return NULL on X call

Question

I have to mock BufferedReader to return values I want:

BufferedReader readerMock = mock(BufferedReader.class);
when(readerMock.readLine())
  .thenReturn("firstLine")
  .thenReturn("secondLine")
  .thenReturn(null);

for (String next = reader.readLine(); next != null; next = reader.readLine())
  do something...

Problem:

readerMock.readLine(); //returns "firstLine" 
readerMock.readLine(); //returns "secondLine"
readerMock.readLine(); //PROBLEM: returns "secondLine" instead of NULL

Question: How to return null on the third call

Answer 1

Works for me (Mockito 1.9.5):

BufferedReader readerMock = mock(BufferedReader.class);
when(readerMock.readLine())
  .thenReturn("firstLine")
  .thenReturn("secondLine")
  .thenReturn(null);

System.out.println(readerMock.readLine());
System.out.println(readerMock.readLine());
System.out.println(readerMock.readLine());

Output:

firstLine
secondLine
null