Build constraints inside a single test suing NUnit.Framework.Constraints.Constraint

NUnit.Framework.Constraints.Constraint.cs

void Main()
{
    // nunit runner
	NUnit.ConsoleRunner.Runner.Main(new string[]
   	{
    	Assembly.GetExecutingAssembly().Location, 
   	});
}

public class ClassUnderTest
{
    public string First { get; set; }
    public string Second { get; set; }
    public string Third { get; set; }
}

[TestFixture]
public class Tests
{
    public IEnumerable TestCasesSourcesSeparateProperties
    {
        get
        {
            yield return new TestCaseData("First",  "foo").SetDescription("Test Property 'First'");
            yield return new TestCaseData("Second", "bar").SetDescription("Test Property 'Second'");;
            yield return new TestCaseData("Third",  "boo").SetDescription("Test Property 'Third'");;
        }
    }
    
    [TestCaseSource("TestCasesSourcesSeparateProperties")]
    public void ClassUnderTest_CheckProperty_ExpectValue(string propertyName, string expectedPropertyValue)
    {
        // Arrange
        ClassUnderTest cut = null;
        
        // Act: perform actual test
        cut = new ClassUnderTest { First =  "foo", Second = "bar",  Third  = "boo" };
        
        // Assert
        Assert.That(cut, Is.Not.Null
                            .And.Property(propertyName).EqualTo(expectedPropertyValue));
    }
    
    public IEnumerable TestCasesSourcesAllProperties
    {
        get
        {
            yield return new TestCaseData(
                new Tuple<string, string>[] { 
                    Tuple.Create("First", "foo"), 
                    Tuple.Create("Second", "bar"), 
                    Tuple.Create("Third", "boo") } as object)
                        .SetDescription("Test all properties using Constraint expression");
        }
    }
    
    // get test parameters from TestCasesSourcesAllProperties
    [TestCaseSource("TestCasesSourcesAllProperties")]
    public void ClassUnderTest_CheckAllProperty_ExpectValues(Tuple<string, string>[] propertiesNamesWithValues)
    {
        // Arrange
        ClassUnderTest cut = null;
        
        // Act: perform actual test, here is only assignment
        cut = new ClassUnderTest { First =  "foo", Second = "bar",  Third  = "boo" };
        
        // Assert
        // check that class-under-test is not null
        NUnit.Framework.Constraints.Constraint expression = Is.Not.Null;
        
        foreach(var property in propertiesNamesWithValues)
        {
            // add constraint for every property one by one
            expression = expression.And.Property(property.Item1).EqualTo(property.Item2);
        }
        
        Assert.That(cut, expression);
    }
}