InMemoryTransactionsRepositoryTest.java

package bank.tests.integration;

// some ommited imports...

public class InMemoryTransactionsRepositoryTest {

  private TransactionsRepository repository;
  private List<Transaction> initialTransactions;

  @Before
  public void setup() throws ParseException {
    repository = new InMemoryTransactionsRepository();
    initialTransactions = Arrays.asList(
        aTransaction().withDeposit(100).on("10/10/2021").build(),
        aTransaction().withWithdrawal(50).on("15/10/2021").build());
    prepareData(initialTransactions);
  }

  @Test
  public void a_transaction_can_be_saved() throws ParseException {
    Transaction transaction = aTransaction().withDeposit(500).on("25/10/2021").build();

    repository.save(transaction);

    assertThat(repository.retrieveAll(), is(addTo(initialTransactions, transaction)));
  }

  @Test
  public void transactions_can_be_retrieved() {
    assertThat(repository.retrieveAll(), is(initialTransactions));
  }

  private void prepareData(List<Transaction> transactions) {
    for (Transaction transaction : transactions) {
      repository.save(transaction);
    }
  }
}