Object Assertions Library

ObjectAssertions is a C# library that provides a code generator for writing robust and future-proof test cases by enabling compile-time checks for all properties of an object.

With ObjectAssertions, developers can easily generate assertions for all properties of their classes and structs by implementing the IAssertsAllPropertiesOf interface. The library is designed to provide compile-time safety by making it impossible to forget to test any newly added properties. If a new property is added to a class, the code won't compile until a corresponding assertion is added.

Quickstart

Let's assume this is class you want to test

public class MyClass
{
    public int MyInt { get; set; }
    public string MyString { get; set; }
    public bool MyBool { get; set; }
}

Add package:

dotnet add package ObjectAssertions.Abstractions
dotnet add package ObjectAssertions.Generator

Define assertions class:

using ObjectAssertions.Abstractions;

public class MyClassAssertions : IAssertsAllPropertiesOf<MyClass>
{
}

Define test:

[Fact]
public void TestMyClass()
{
    var myClass = new MyClass { MyInt = 5, MyString = "Hello", MyBool = true };
    var assertions = new MyClassAssertions(myClass)
    {
        MyInt = i => Assert.Equal(5, i),        
        MyString = s => Assert.Equal("Hello", s),
        MyBool = b => Assert.Equal(true, b),
        IgnoredProperty = ObjectAssertionsHelpers.Ignore<Foo>("Not in test scope"")
    };

    assertions.Assert();
}

All delegates passed to object initializer will be invoked within .Assert() call. You can use ObjectAssertionsHelpers.Ignore<T>(string reason) method to ignore certain assertions and express intent.

Assertion library integrations

FluentAssertions

Use AssertionScope class:

using (new AssertionScope())
{
    new MyClassAssertions(myClass)
    {
        MyInt = i => i.Should().Be(5),        
        MyString = s => s.Should().Be("Hello"),
        MyBool = b => Should().Be(true),
        IgnoredProperty = ObjectAssertionsHelpers.Ignore<Foo>("Not in test scope"")
    }.Assert();
}

NUnit

Use Assert.Multiple method:

Assert.Multiple(() =>
{
    new MyClassAssertions(myClass)
    {
        MyInt = i => Assert.AreEqual(5, i),        
        MyString = s => Assert.AreEqual("Hello", s),
        MyBool = b => Assert.AreEqual(true, b),
        IgnoredProperty = ObjectAssertionsHelpers.Ignore<Foo>("Not in test scope"")
    }.Assert();
}

Shoudly

Use ShouldSatisfyAllConditions extension method:

var assertions = new MyClassAssertions(myClass)
{
    MyInt = i => i.ShouldBe(5),        
    MyString = s => s.ShouldBe("Hello"),
    MyBool = b => ShouldBe(true),
    IgnoredProperty = ObjectAssertionsHelpers.Ignore<Foo>("Not in test scope"")
}.CollectAssertions();

myClass.ShouldSatisfyAllConditions(assertions);