public void Get_NonExistingElement_ShouldThrowException()
    {
        // Arrange
        var dictionary = new DictionaryDataStructure.Dictionary<int, string>();

        // Act
        dictionary.Get(12345);
    }
    public void Get_ExistingElement_ShouldReturnTheValue()
    {
        // Arrange
        var dictionary = new DictionaryDataStructure.Dictionary<int, string>();

        // Act
        dictionary.Add(555, "Peter");
        var actualValue = dictionary.Get(555);

        // Assert
        Assert.AreEqual("Peter", actualValue);
    }