InMemoryAccountRepository implements AccountRepository { @Override public int getNumberOfAccounts() { return accountMap.size(); }  @Override List<Account> getAccounts(); @Override Account getAccount(Long id); @Override int getNumberOfAccounts(); @Override Long createAccount(BigDecimal initialBalance); @Override int deleteAccount(Long id); @Override void updateAccount(Account account);  }
@Test public void testGetNumberOfAccounts() throws Exception { assertThat(repository.getNumberOfAccounts(), is(3)); }