How to use Exclude in FluentAssertions for property in collection?

Question

I have two classes:

public class ClassA
{
  public int? ID {get; set;}
  public IEnumerable<ClassB> Children {get; set;}
}

public class ClassB
{
  public int? ID {get; set;}
  public string Name {get; set;}
}

I want to use fluent assertions to compare to ClassA instances. However I want to ignore the IDs (because the IDs will have been assigned after the save).

I know I can do this:

expectedA.ShouldBeEquivalentTo(actualA, options => options.Excluding(x => x.PropertyPath == "Children[0].ID"));

Which I can obviously repeat for each ClassB in the collection. However I'm looking for a way to exclude the all the IDs (rather than doing an exclude for each element).

I've read this question however if I remove the [0] indexers the assertions fail.

Is this possible?

score 68 · Accepted Answer · edited Feb 14 '17 at 10:03

68

What about?

expected.ShouldBeEquivalentTo(actualA, options => options.Excluding(su => 
   (su.RuntimeType == typeof(ClassB)) && (su.PropertyPath.EndsWith("Id")));`

Or you could do a RegEx match on the property path, such as

expected.ShouldBeEquivalentTo(actualA, options => options.Excluding(su => (Regex.IsMatch
   ("Children\[.+\]\.ID"));

I actually like that last one, but the regex stuff makes it a bit difficult to read. Maybe I should extend ISubjectInfo with a method to match the path against a wildcard pattern, so that you can do this:

expected.ShouldBeEquivalentTo(actualA, options => options
  .Excluding(su => su.PathMatches("Children[*].ID")));

edited Feb 14 '17 at 10:03

superjos

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answered Mar 04 '14 at 20:25

Dennis Doomen

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I'm going to mark this one as the answer as the regex in an extension method is the approach I went with in the end – Liath Mar 05 '14 at 06:22
3

How has this changed in more recent versions of FluentAssertions? I'm not sure `PropertyPath` is still there – superjos Feb 14 '17 at 09:52
1

I tried both options without success, but was able to fix RegEx option to work with current version - see https://stackoverflow.com/questions/22142576/how-to-use-exclude-in-fluentassertions-for-property-in-collection/51858245#51858245 . By the way, the new name for PropertyPath is SelectedMemberPath – Michael Freidgeim Aug 15 '18 at 12:00
2

`Regex.IsMatch(x.SelectedMemberPath, @"Children\[\d+\]\.ID")` – Saro Taşciyan Aug 08 '19 at 20:30
1

FluentAssertions v6 removed SelectedMemberPath the solution here is: options => options.Excluding((IMemberInfo x) => x.DeclaringType == typeof(ClassB) && x.Path.EndsWith("Id")) – Lakedaimon Aug 13 '21 at 13:06
`SelectedMemeberPath` was renamed to `Path` in v.6.0.0: https://fluentassertions.com/releases/#600 – xavier Apr 08 '22 at 12:27

score 39 · Answer 2 · answered Aug 12 '15 at 18:16

I've just come across a similar problem and the latest version of FluentAssertions has changed things a bit.

My objects contains dictionaries of other objects. The objects in the dictionaries contain other objects that I want to exclude. The scenario I have is around testing Json serialization where I ignore certain properties.

This works for me:

gotA.ShouldBeEquivalentTo(expectedB , config => 
  config
    .Excluding(ctx => ctx.SelectedMemberInfo.MemberType == typeof(Venue))
    .Excluding(ctx => ctx.SelectedMemberInfo.MemberType == typeof(Exhibit))
    .Excluding(ctx => ctx.SelectedMemberInfo.MemberType == typeof(Content))
    .Excluding(ctx => ctx.SelectedMemberInfo.MemberType == typeof(Survey))
    .Excluding(ctx => ctx.SelectedMemberInfo.MemberType == typeof(Media))
  );

Took some time to work out how to do it, but it's really useful!

For what it is worth, you can also pass in an anonymous object as the expectation since FA 5 and include only the properties you care about. — Dennis Doomen, Aug 10 '19 at 08:21

score 19 · Answer 3 · answered Jun 11 '22 at 14:37

19

This is supported by FluentAssertions 6.7

actualA.Should().BeEquivalentTo(expectedA, options =>
    options
       .For(a => a.Children)
       .Exclude(b => b.ID));

answered Jun 11 '22 at 14:37

Bouke Versteegh

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score 16 · Answer 4 · answered Mar 03 '14 at 09:41

16

Simple way would be to set assertions on collection directly, combined with its exclusion on ClassA equivalency assertion:

expectedA.ShouldBeEquivalentTo(expectedB,
   o => o.Excluding(s => s.PropertyInfo.Name == "Children"));
expectedA.Children.ShouldBeEquivalentTo(expectedB.Children,
   o => o.Excluding(s => s.PropertyInfo.Name = "Id"));

answered Mar 03 '14 at 09:41

k.m

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I think Propertyinfo does no longer exist. SelectedMemberInfo.Name should do it instead. – thomasgalliker Aug 06 '19 at 10:22

score 10 · Answer 5 · answered Dec 14 '21 at 11:00

There are a few valid answers here, but I am adding another one that does not involve stringly-typed expressions.

expectedA.ShouldBeEquivalentTo(expectedB, o => o.Excluding(s => s.Children));
expectedA.Children.ShouldBeEquivalentTo(expectedB.Children, o => o.Excluding(s => s.Id));

score 6 · Answer 6 · answered Jan 15 '21 at 14:50

The ShouldBeEquivalentTo method seems to be obsolete now, in order to get path for the accepted answer you can use the Excluding overload with IMemberInfo.SelectedMemberPath instead:

expected.Should().BeEquivalentTo(actualA, options => 
    options.Excluding((IMemberInfo mi) => mi.SelectedMemberPath.EndsWith("ID")));

score 4 · Answer 7 · answered Aug 15 '18 at 11:56

4

Based on RegEx match idea from Dennis Doomen‘s answer I was able to make it working

expected.ShouldBeEquivalentTo(actualA, options =>
  options.Excluding(su => 
     (Regex.IsMatch(su.SelectedMemberPath, "Children\\[.+\\].ID"));

Difference with Dennis answer: passing su.SelectedMemberPath, double back slashes to escape square brackets.

answered Aug 15 '18 at 11:56

Michael Freidgeim

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`SelectedMemeberPath` was renamed to `Path` in v.6.0.0 https://fluentassertions.com/releases/#600 – xavier Apr 08 '22 at 12:28

score 4 · Answer 8 · answered Mar 29 '22 at 07:04

actual.Should().BeEquivalentTo(expected,
  assertionOptions => assertionOptions
    .Excluding(x => x.CreationTimestamp))

BUT if you work with structs and class overriding equals, then you should change the default comparing with ComparingByMembers https://fluentassertions.com/objectgraphs/#value-types

actual.Should().BeEquivalentTo(expected,
  assertionOptions => assertionOptions
    .Excluding(x => x.CreationTimestamp)
    .ComparingByMembers<T>())

score 1 · Answer 9 · edited May 18 '18 at 06:58

1

The easiest way is:

expected.ShouldBeEquivalentTo(actual, config => config.ExcludingMissingMembers());

edited May 18 '18 at 06:58

cSteusloff

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answered May 18 '18 at 06:30

Michał Chudzik

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OP asked to exclude some existing (NOT Missing) members. – Michael Freidgeim Aug 15 '18 at 02:02

score 1 · Answer 10 · answered Mar 23 '21 at 15:20

1

I thinks the syntax is something like

       actual.Should().BeEquivalentTo(
        expected, 
        config => config.Excluding(o => o.Id).Excluding(o => o.CreateDateUtc) });

answered Mar 23 '21 at 15:20

Alan Machado

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score 0 · Answer 11 · answered Jun 03 '20 at 20:48

An extension class where you can pass a list of expressions

public static class FluentAssertionsExtensions {
    public static EquivalencyAssertionOptions<T> ExcludingNextProperties<T>(
        this EquivalencyAssertionOptions<T> options,
        params Expression<Func<T, object>>[] expressions) {
        foreach (var expression in expressions) {
            options.Excluding(expression);
        }

        return options;
    }
}

Usage

actual.Should().BeEquivalentTo(expected, 
            config => config.ExcludingNextProperties(
                o => o.Id, 
                o => o.CreateDateUtc))

How to use Exclude in FluentAssertions for property in collection?

11 Answers11

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