### Question:
VersionUidHelper { public static UUID extractUUID(String versionUid) { Matcher matcher = UUID_PATTERN.matcher(versionUid); if (matcher.find()) { return UUID.fromString(matcher.group(1)); } return null; } VersionUidHelper(String versionUid); static boolean isVersionUid(String testString); static boolean isUUID(String testString); static boolean isSystemId(String testString); static boolean isVersion(String testString); static UUID extractUUID(String versionUid); static String extractSystemId(String versionUid); static int extractVersion(String versionUid); String toString(); UUID getUuid(); void setUuid(UUID uuid); String getSystemId(); void setSystemId(String systemId); int getVersion(); void setVersion(int version); static final Pattern UUID_PATTERN; static final Pattern VERSION_PATTERN; static final Pattern SYSTEM_ID_PATTERN; static final Pattern VERSION_UID_PATTERN; }### Answer:
@Test public void extractsUUID() { UUID expected = UUID.fromString("1234abcd-5678-ef12-ab34-cd56ef78ab90"); assertThat(VersionUidHelper.extractUUID(VALID_VERSION_UID)).isEqualTo(expected); }