Don't forget to test parallell actions

parallell.cs

/* Lock dictionary between read and write */
public T Do(string key, Func<T,T> func){
    lock (_dictionary) {
        var originalValue = get<T>(key);
        var newValue = func(originalValue);
        set(key, newValue);
        return newValue;
    }
}

/* Test for parallell actions on dictionary */
public void TestAdd1()
{
    var s = EsentKeyValue.GetStore<int>("bar");
    s.Do("counter", t => t + 1);            
}

[TestMethod]
public void ParallellTest()
{
    var s = EsentKeyValue.GetStore<int>("storename");
    s.Set("counter", 0);

    Parallel.Invoke(
        () => TestAdd1(),
        () => TestAdd1(),
        () => TestAdd1());

    var result = s.Get("counter");

    Assert.AreEqual(3, result); /* if I don't lock the dictionary the I can get 1,2 or 3 */

}