title: Assert uniqueness of fields in list
body: <p>I have made a list in C# and I want to make a test to see if all the values of the Id fields are unique. </p>
  
  <pre><code>public static List&lt;RestaurantReview&gt; _reviews = new List&lt;RestaurantReview&gt;
  {
      new RestaurantReview
      {
          Id = 1,
          Name = "McDonalds",
      },
      new RestaurantReview
      {
          Id = 2,
          Name = "Burger King",
      },
  }
  </code></pre>
  
  <p>Because I did some debugging I fount out that it is running trough the list but I do not get the proper test value. Could someone please explain what I am doing wrong here?</p>
  
  <pre><code>[TestMethod()]
  public void CheckReviewIds()
  {
      var FirstReview = ReviewsController._reviews.First();
      bool AllUniqueIds = ReviewsController._reviews.All(s =&gt; s.Id == FirstReview.Id);
  
      Assert.IsFalse(AllUniqueIds);
  
  }
  </code></pre>
  
  <p>Thanks in advance. </p>