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c#unit-testingjson.netassertionfluent-assertions

How to compare two Json objects using C#


I have two Json objects as below need to be compared. I am using Newtonsoft libraries for Json parsing.

string InstanceExpected = jsonExpected;
string InstanceActual = jsonActual;
var InstanceObjExpected = JObject.Parse(InstanceExpected);
var InstanceObjActual = JObject.Parse(InstanceActual);

And I am using Fluent Assertions to compare it. But the problem is Fluent assertion fails only when the attribute count/names are not matching. If the json values are different it passes. I require to fail when values are different.

InstanceObjActual.Should().BeEquivalentTo(InstanceObjExpected);

For example I have the actual and expected json to compare as below. And using the above way of comparing make them Pass which is wrong.

{
  "Name": "20181004164456",
  "objectId": "4ea9b00b-d601-44af-a990-3034af18fdb1%>"  
}

{
  "Name": "AAAAAAAAAAAA",
  "objectId": "4ea9b00b-d601-44af-a990-3034af18fdb1%>"  
}

Solution

  • I did a bit more digging and was able to find out why the OP's test code doesn't run as expected. I was able to fix it by installing and using the FluentAssertions.Json nuget package.

    One important thing:

    Be sure to include using FluentAssertions.Json otherwise false positives may occur.

    Test code is the following:

    using FluentAssertions;
    using FluentAssertions.Json;
    using Newtonsoft.Json;
    using Newtonsoft.Json.Linq;
    using NUnit.Framework;
    
    [TestFixture]
    public class JsonTests
    {
        [Test]
        public void JsonObject_ShouldBeEqualAsExpected()
        {
            JToken expected = JToken.Parse(@"{ ""Name"": ""20181004164456"", ""objectId"": ""4ea9b00b-d601-44af-a990-3034af18fdb1%>"" }");
            JToken actual = JToken.Parse(@"{ ""Name"": ""AAAAAAAAAAAA"", ""objectId"": ""4ea9b00b-d601-44af-a990-3034af18fdb1%>"" }");
    
            actual.Should().BeEquivalentTo(expected);
        }
    }
    

    Running the test:

    Unit test results