c# - Compare equality between two objects in NUnit

Question

I'm trying to assert that one object is "equal" to another object.

The objects are just instances of a class with a bunch of public properties. Is there an easy way to have NUnit assert equality based on the properties?

This is my current solution but I think there may be something better:

Assert.AreEqual(LeftObject.Property1, RightObject.Property1)
Assert.AreEqual(LeftObject.Property2, RightObject.Property2)
Assert.AreEqual(LeftObject.Property3, RightObject.Property3)
...
Assert.AreEqual(LeftObject.PropertyN, RightObject.PropertyN)

What I'm going for would be in the same spirit as the CollectionEquivalentConstraint wherein NUnit verifies that the contents of two collections are identical.

Answer 1

Do not override Equals just for testing purposes. It's tedious and affects domain logic. Instead,

Use JSON to compare the object's data

No additional logic on your objects. No extra tasks for testing.

Just use this simple method:

public static void AreEqualByJson(object expected, object actual)
{
    var serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
    var expectedJson = serializer.Serialize(expected);
    var actualJson = serializer.Serialize(actual);
    Assert.AreEqual(expectedJson, actualJson);
}

It seems to work out great. The test runner results info will show the JSON string comparison (the object graph) included so you see directly what's wrong.

Also note! If you have bigger complex objects and just want to compare parts of them you can (use LINQ for sequence data) create anonymous objects to use with above method.

public void SomeTest()
{
    var expect = new { PropA = 12, PropB = 14 };
    var sut = loc.Resolve<SomeSvc>();
    var bigObjectResult = sut.Execute(); // This will return a big object with loads of properties 
    AssExt.AreEqualByJson(expect, new { bigObjectResult.PropA, bigObjectResult.PropB });
}