如何为equals方法编写测试用例

Question

How would I go about writing a test case for this equals method that compares ID numbers after it checks if an object is an "Integer" or "Patron".

Here is the method:

public boolean equals(Object other) {
   
      boolean bool = false;
      
      if (other instanceof Patron) {
         Patron patron = (Patron) other;
         bool = this.idNumber == patron.idNumber;
      } else if (other instanceof Integer) {
         Integer id = (Integer) other;
         bool = this.idNumber == id;
      }
      return bool;

Answer 1

If you want to verify whether the contract for the equals and hashCode methods is met, I would suggest using EqualsVerifier .

If you don't want to use an external library, I would suggest taking a look at it to get an idea of what (and why) you need to test. It is a great source to learn about equals and hashCode .

It's very simple to write a test:

EqualsVerifier.forClass(Foo.class).verify();

There's also a less strict alternative:

EqualsVerifier.simple()
            .forClass(Foo.class).verify();

It also has several options to suppress other warnings.