An example of how to use argument captor.

ArgumentCaptor.java

@Test
public void saveCustomer_savesTheCustomerToTheDatabase() {
    // Arrange
    ArgumentCaptor<Customer> argumentCaptor = ArgumentCaptor.forClass(Customer.class);
    Customer customer = new Customer(123, "Sam");
    // Act
    Customer result = customerService.saveCustomer(customer);
    // Assert
    verify(mockCustomerRepository, times(1))
            .save(argumentCaptor.capture());
    assertThat(argumentCaptor.getValue())
            .isEqualToIgnoringGivenFields(customer, "timeStamp");
}