### Question:
ClassNameUtils { public static String getPackageName(String className) { String sourceName = toFormat(className, TypeFormat.SOURCE); int lastIndex = sourceName.lastIndexOf('.'); if (lastIndex < 0) { return ""; } return sourceName.substring(0, lastIndex); }  static String binaryToInternal(String binaryName); static String getComponentBase(String className); static String getComponentType(String className); static int getDimensionCount(String className); static String getPackageName(String className); static @Nullable String getPrimitive(String className); static Class<?> getPrimitiveClass(String className); static @Nullable String getWrapper(String className); static String internalToBinary(String internalName); static String internalToSource(String internalName); static boolean isObject(String type); static boolean isPrimitive(String className); static boolean isPrimitiveOrWrapper(String className); static boolean isWrapper(String className); static String sourceToBinary(String sourceName); static String sourceToInternal(String sourceName); static String toFormat(String className, TypeFormat format); static String toInternal(Class<?> klazz); static List<String> toInternal(Class<?>... classes); static ReferenceType guessReferenceType(@Nonnull String s);  }### Answer:
@Test public void canGetPackageName() { assertEquals("some.package", ClassNameUtils.getPackageName("Lsome/package/Class;")); assertEquals("", ClassNameUtils.getPackageName("LSomeClass;")); assertEquals("", ClassNameUtils.getPackageName("SomeClass")); assertEquals("", ClassNameUtils.getPackageName("SomeClass[]")); assertEquals("", ClassNameUtils.getPackageName("[LSomeClass;")); }