java - Mockito bypass static method for testing

Question

I need to test handleIn() method using Mockito.

However the code need to call this legacy code Util.getContextPDO which is a static method.

Note that in testing environment this Util.getContextPDO is always returns Exception, and I intend to bypass this Util.getContextPDO() by always return a dummy IPDO.

public class MyClass {
  public IPDO getIPDO() 
  {
    return Util.getContextPDO(); // note that Util.getContextPDO() is a static, not mockable.
  }

  public String handleIn(Object input) throws Throwable 
  {
    String result = "";
    IPDO pdo = getIPDO();

    // some important business logic.

    return result;
  } 
}

Initially I thought this achieveable by using spy() of the class "MyClass", so I can mock the return value of getIPDO(). Below is my initial effort using spy ()

@Test
public void testHandleIn() throws Exception
{
    IPDO pdo = new PDODummy();


    MyClass handler = new MyClass ();
    MyClass handler2 = spy(handler);

    when(handler2.getIPDO()).thenReturn(pdo);
    PDOUtil.setPDO(pdo, LogicalFieldEnum.P_TX_CTGY, "test123");
    IPDO pdoNew = handler2.getIPDO();

    Assert.assertEquals("test123,(PDOUtil.getValueAsString(pdoNew, LogicalFieldEnum.P_TX_CTGY)));

}

However the when(handler2.getIPDO()).thenReturn(pdo); is throwing the Exception that I want to avoid ( because handler2.getIPDO() ) seems to call the real method.

Any idea on how to test this part of code?

Answer 1

Changed my testing to :

@Test
public void testHandleIn() throws Exception
{
  IPDO pdo = new PDODummy();


  MyClass handler = new MyClass ();
  MyClass handler2 = spy(handler);

  doReturn(pdo ).when( handler2 ).getIPDO();
  PDOUtil.setPDO(pdo, LogicalFieldEnum.P_TX_CTGY, "test123");
  IPDO pdoNew = handler2.getIPDO();

  Assert.assertEquals("test123,(PDOUtil.getValueAsString(pdoNew, LogicalFieldEnum.P_TX_CTGY)));

}

Solved after reading Effective Mockito.