In my Android project I decided to create wrapper around SharedPreferences(which is basically key-value storage) with following interfaceinterface Preferences{    public void saveInt(int value, String key);    public void saveString(String value, String key);    public int readInt(String key);    public String readString(String key);}Implemetation uses Android SharedPreferences API, simplified version looks like that:public class SharedPrefencesWrapper implements Preferences{    private SharedPreferences mSharedPreferences;    public SharedPreferencesStorage(Context context) {        mSharedPreferences = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);    }    public void saveInt(int value, String key){        mSharedPreferences.edit().putInt(key, value).commit();    }    //The same for all other public methods}Now I want to test SharedPreferencesWrapper class, every public method of Preferences class:public class SharedPreferencesWrapperTest{    @Test    public void savesBoolean(){       Preferences prefs = new SharedPreferencesWrapper(...);       prefs.saveInt(3, intKey);       int savedValue = prefs.readInt(intKey);       assertEquals(3, savedValue);    }}Now, can the test look like that? Or should I use SharedPreferences API to check saved values in tests? My concern is that to retrieve the value I will use methods of SharedPrefencesWrapper, something doesn't feel right here. 
Testing strategy for wrapper class
java;unit testing;testing;junit