### Question:
FbWalletUtil { public static String getAccount(String path) { try { int beginIndex = path.indexOf("---"); if (beginIndex == -1) { return null; } return path.substring(beginIndex + 3); } catch (Exception ex) { LOG.warn(ex.getMessage()); return null; } }  static Integer getWalletFileVersion(Path path); static Integer getWalletFileVersion(String path); static String getAccount(String path); static ApolloFbWallet buildWallet(byte[] keyStore, String passPhrase);  }### Answer:
@Test void getAccount() { String account1 = FbWalletUtil.getAccount("/Users/user/.apl-blockchain/apl-blockchain-vault-keystore/a2e9b9/v1_2019-03-19_13-58-16---APL-9ES6-JTW3-JBN4-7LLZQ"); String account0 = FbWalletUtil.getAccount("/Users/user/.apl-blockchain/apl-blockchain-vault-keystore/a2e9b9/v0_2019-03-19_13-58-16---APL-9ES6-JTW3-JBN4-7LLZ1"); assertTrue(Objects.equals("APL-9ES6-JTW3-JBN4-7LLZQ", account1)); assertTrue(Objects.equals("APL-9ES6-JTW3-JBN4-7LLZ1", account0)); }
@Test void getAccountWhenFileNameNotValid() { String account = FbWalletUtil.getAccount("v1_2019-03-19_13-58-16-APL-9ES6-JTW3-JBN4-7LLZ"); assertNull(account); }