### Question:
FbWalletUtil { public static Integer getWalletFileVersion(Path path) { return getWalletFileVersion(path.toString()); }  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 getWalletFileVersion() { Integer version1 = FbWalletUtil.getWalletFileVersion(String.join(File.separator, "a2e9b9", "v1_2019-03-19_13-58-16---APL-9ES6-JTW3-JBN4" + "-7LLZQ")); Integer version0 = FbWalletUtil.getWalletFileVersion(String.join(File.separator, "a2e9b9", "v0_2019-03-19_13-58-16---APL-9ES6-JTW3-JBN4-7LLZQ")); assertTrue(Objects.equals(1, version1)); assertTrue(Objects.equals(0, version0)); }
@Test void getWalletFileVersionWhenFileNameNotValid() { Integer version1 = FbWalletUtil.getWalletFileVersion("/Users/user/.apl-blockchain/apl-blockchain-vault-keystore/a2e9b9/vd_2019-03-19_13-58-16---APL-9ES6-JTW3-JBN4-7LLZQ"); Integer version2 = FbWalletUtil.getWalletFileVersion("/Users/user/.apl-blockchain/apl-blockchain-vault-keystore/a2e9b9/1_2019-03-19_13-58-16---APL-9ES6-JTW3-JBN4-7LLZQ"); assertNull(version1); assertNull(version2); }