package org.jmock;

import org.jmock.integration.junit4.JUnit4Mockery;
import org.junit.Test;

/**
 * JUnit to demonstrate a possible bug dealing with mocking a parameter passed to a mock object.
 */
public class JMockErrorExample
{
    /**
     * Shows an error in JMock.
     */
    @Test
    public void testMockErrorExample()
    {
        final Mockery context = new JUnit4Mockery();
        final TestObject testObject = context.mock(TestObject.class);

        context.checking(new Expectations()
        {
            {
                // The error will occur on the next line.
                one(testObject).testMethod(with(same(getMockTestParameter(context))));
            }
        });

        testObject.testMethod(getMockTestParameter(context));
        context.assertIsSatisfied();
    }

    /**
     * Shows a workaround to the above error.
     */
    @Test
    public void testMockNoErrorExample()
    {
        final Mockery context = new JUnit4Mockery();
        final TestObject testObject = context.mock(TestObject.class);

        // Somehow, storing off the return from getMockTestParameter(Mockery) solves the problem.
        final TestParameter testParameter = getMockTestParameter(context);

        context.checking(new Expectations()
        {
            {
                one(testObject).testMethod(with(same(testParameter)));
            }
        });

        testObject.testMethod(getMockTestParameter(context));
        context.assertIsSatisfied();
    }

    private TestParameter mockTestParameter; // We store off this guy so the getMockTestParameter(Mockery) method always returns the "same" object.

    /**
     * Creates and returns a mock TestParameter for the given {@link Mockery} context.
     * @param context The {@link Mockery} context for which to create the mock object (cannot be null).
     * @return A non-null mocked {@link TestParameter}.
     */
    private TestParameter getMockTestParameter(final Mockery context)
    {
        if (mockTestParameter == null)
        {
            final TestParameter newMockTestParameter = context.mock(TestParameter.class);

            context.checking(new Expectations()
            {
                {
                    allowing(newMockTestParameter).testMethod();
                }
            });

            mockTestParameter = newMockTestParameter;
        }

        return mockTestParameter;
    }

    /**
     * The parameter that will be mocked.
     */
    private interface TestParameter
    {
        public void testMethod();
    }

    /**
     * The object that will be mocked.
     */
    private interface TestObject
    {
        public void testMethod(final TestParameter testParameter);
    }
}