Question

This might seem like a pretty detailed question about Easymock, but I’m having a hard time finding a support site/forum/mailing list for this library.

I’m encountering a bug when using the captures() method that seems to return the captured parameters out of order.

Here’s a simplified version of what I am testing:

public class CaptureTest extends TestCase {      // interface we will be mocking     interface Processor {             void process(String x);     }      // class that uses the interface above which will receive the mock     class Component {          private Processor processor;          private String[] s = { 'one', 'two', 'three', 'four' };          Component(Processor processor) {             this.processor = processor;         }          public void doSomething() {             for (int i = 0; i < s.length; i++) {                 processor.process(s[i]);             }         } }      public void testCapture() {          //create the mock, wire it up             Processor mockProcessor = createMock(Processor.class);         Component component = new Component(mockProcessor);          //we're going to call the process method four times         //with different arguments, and we want to capture          //the value passed to the mock so we can assert against it later             Capture<String> cap1 = new Capture<String>();         Capture<String> cap2 = new Capture<String>();         Capture<String> cap3 = new Capture<String>();         Capture<String> cap4 = new Capture<String>();          mockProcessor.process(and(isA(String.class), capture(cap1)));         mockProcessor.process(and(isA(String.class), capture(cap2)));         mockProcessor.process(and(isA(String.class), capture(cap3)));         mockProcessor.process(and(isA(String.class), capture(cap4)));          replay(mockProcessor);          component.doSomething();          //check what values were passed to the mock         assertEquals('one', cap1.getValue());         assertEquals('two', cap2.getValue());         assertEquals('three', cap3.getValue());         assertEquals('four', cap4.getValue());          verify(mockProcessor);     }  } 

(Please note that this is just a simplified test case – I know that I could specify the exact value of the arguments I expect passed to my mock, but in my real case the arguments are complex objects with a handful of fields, and I want to capture the object so I can assert against just a few of those fields without re-creating the entire object in my test case).

When I run the test, it fails at:

junit.framework.ComparisonFailure: expected:<[one]> but was:<[four]>

Meaning that the parameter that EasyMock is capturing in cap1 is not the first call to the method, but the last (since the value is four). I get the same results if I reverse the captures() declarations, i.e. use cap4 with the first method call, etc.

This seems like it might be a bug within EasyMock – different parameters passed to the same method in different invocations don’t seem to be capture correctly.

Is anyone else using capture() with EasyMock and having similar problems? Is there an easy workaround you know of, or a different way I can capture the parameters being passed to my mock’s methods?

Update 1: fixed code sample to show I am using createMock, not createStrictMock, but I get the same error with both (although the actual value of what is captured changes).

Answer 1

I’ve received an answer on the bug I submitted to the Easymock sourceforge site, and a developer has confirmed it is indeed a bug with this version of Easymock.

It is indeed a bug. The capture is done even if it was already done. The current workaround is to implement your own capture object and override setValue to do this:

@Override public void setValue(T value) {   if(!hasCaptured()) {     super.setValue(value);   } }