hamcrest 1.3 hasItems fails test when comparing identical lists

Question

The following line fails when trying to compare 2 lists:

import static org.hamcrest.CoreMatchers.*;
import static org.hamcrest.MatcherAssert.assertThat;

assertThat(
    actualDealSummary.getDeals(), 
    hasItems(expectedDealSummary.getDeals().toArray(new Deal[expectedDealSummary.getDeals().size()])));

Using JUnit 4.11, and hamcrest-all (1.3):

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.11</version>
    <scope>test</scope>
    <exclusions>
        <exclusion>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-core</artifactId>
        </exclusion>
    </exclusions>
</dependency>

<dependency>
    <groupId>org.hamcrest</groupId>
    <artifactId>hamcrest-all</artifactId>
    <version>1.3</version>
</dependency>

I just want to check that the actual list has the expected list's values, but I get the following error:

java.lang.AssertionError: 
Expected: (a collection containing <SIXRxrImUE> and a collection containing <RQjVbVRlyG> and a collection containing <avnKxogdyN>)
     but: a collection containing <SIXRxrImUE> was <SIXRxrImUE>, was <RQjVbVRlyG>, was <avnKxogdyN>
    at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:20)
    at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:8)
    at 

How can I use hamcrest's built in Matchers to compare 2 lists of pojos?

Answer 1

Your Deal class will need to implement equals for this to work. You may find it simpler to check for equality:

assertEquals(expectedDealSummary.getDeals(), actualDealSummary.getDeals());

Note that hasItems is performing a slightly different check to this and confirming that the actual list is a superset of the expected list; this would cause it to pass even if unexpected items were also present.