FullNameUnitTest_Best.cs

[Test]
public void FullNameConcatenatesFirstAndLastName()
{
    // Arrange
    Person personUnderTest = new()
    {
        FirstName = "SomeFirstName",
        LastName = "SomeSecondName",
        Email = "Any.Email@anywhere.co.uk"
    };

    // Act
    var fullName = personUnderTest.FullName;

    // Assert
    Assert.AreEqual("SomeFirstName SomeSecondName", fullName);
}