How to compare two lists with AssertJ

As an automation tester, I want to compare two lists to prove those are equal or not. To do that, I can use function of AssertJ library (assertj-core) to compare two list

Prerequisite

To using AssertJ we have to add dependency into pom.xml file

<!-- https://mvnrepository.com/artifact/org.assertj/assertj-core -->
        <dependency>
            <groupId>org.assertj</groupId>
            <artifactId>assertj-core</artifactId>
            <version>3.22.0</version>
            <scope>test</scope>
        </dependency>

Compare two lists objects

Example

I have some lists of user class

    static List<User> firstList = new ArrayList<>();
    static List<User> secondList = new ArrayList<>();
    static List<User> thirdList = new ArrayList<>();
    static List<User> fourthList = new ArrayList<>();

    //Original list
    firstList.add(new User("A",12,true,123.12));
    firstList.add(new User("B",14,true,888));
    firstList.add(new User("C",13,false,999));

    //Same original list but different order
    secondList.add(new User("A",12,true,123.12));
    secondList.add(new User("C",13,false,999));
    secondList.add(new User("B",14,true,888));

    //Same original list
    thirdList.add(new User("A",12,true,123.12));
    thirdList.add(new User("B",14,true,888));
    thirdList.add(new User("C",13,false,999));

I want to compare 2 lists with order and ignore order.

Compare 2 lists with order

Using following function we can compare two list that compare with order.

    @Test
    public void compare_with_order_with_2_equal_lists_have_same_order(){
        assertThat(firstList).usingRecursiveComparison()
                .isEqualTo(thirdList);
    }

Compare 2 lists ignore order

Using following function we can compare two list and ignore about the order of items.

    @Test
    public void compare_ignore_order_with_2_equal_objects_have_different_order(){
        assertThat(firstList).usingRecursiveComparison().ignoringCollectionOrder()
                .isEqualTo(secondList);
    }

Compare two lists String

Example

I have some lists of String class.

    static List<String> firstList = new ArrayList<>();
    static List<String> secondList = new ArrayList<>();
    static List<String> thirdList = new ArrayList<>();
    static List<String> fourthList = new ArrayList<>();

   //Original list
    firstList.add("A");
    firstList.add("B");
    firstList.add("C");

    //Same original list but different order
    secondList.add("A");
    secondList.add("C");
    secondList.add("B");

    //Same original list
    thirdList.add("A");
    thirdList.add("B");
    thirdList.add("C");

I want to compare those lists with order and ignore order.

Compare 2 lists with order

Using following function we can compare two list that compare with order.

    @Test
    public void compare_with_order_with_2_equal_lists_have_same_order(){
        assertThat(firstList).usingRecursiveComparison()
                .isEqualTo(thirdList);
    }

Compare 2 lists ignore order

Using following function we can compare two list that compare ignore order.

    @Test
    public void compare_with_order_with_2_equal_lists_have_different_order(){
        assertThat(firstList).usingRecursiveComparison()
                .isEqualTo(thirdList);
    }

Compare two lists Interger, Float and Double

We use the function to compare like the function that is used for two list String