BeEquivalentTo fails when comparing two JsonElement's

Test is failing when comparing two Json Elements using ShouldBeEquivalentTo. I’m sure that this Assertion

[Fact]
public void Test()
{
    // Arrange & Act
    var element1 = JsonDocument.Parse("{}").RootElement;
    var element2 = JsonDocument.Parse("{}").RootElement;

    // Assert
    element1.Should().BeEquivalentTo(element2);
}

Expected behavior:

I would expect this to pass

Actual behavior:

This actually fails

Versions

XUnit v2.4.1 FluentAssertions v5.9.0 .NET Core 3.0

[jnyrup]

@dennisdoomen JsonElement is from System.Text.Json not Newtonsoft.Json.

[jnyrup]

Analysis: JsonElement is a struct that does not override Object.Equals(object). That is, it keeps the default generated ValueType.Equals(object) which compares instances memberwise using their Equals(object).

JsonElement has a field _parent, which points to its parent JsonDocument. JsonDocument also does not override Object.Equals(object), so instances are compared by reference.

As the _parent fields of element1 and element2 points to two different JsonDocuments in memory, element1 does not equal element2.

This behavior can be seen with

element1.Equals(element2); // false

Workaround: If you use ComparingByMembers() Fluent Assertions will compare object structurally (think memberwise), but per default only for public members. So it will now exclude _parent.

element1.Should().BeEquivalentTo(element2, opt => opt.ComparingByMembers<JsonElement>());