FluentAssertions.LanguageExt

• See LanguageExt C# Functional Programming Language Extensions for more information about functional-programming 'base class library'.
• See FluentAssertions for more information about the extensive set of extension methods for unit tests.

Special thanks to @sparerd for the many new features.

Nuget

Install-Package FluentAssertions.LanguageExt

FluentAssertions.LanguageExt

Option, OptionAsync and OptionUnsafe

Methods

• BeSome()
• BeSome(expected)
• BeSome(action)
• BeNone()

Example Usage

using FluentAssertions;
using FluentAssertions.LanguageExt;

... 
var option = Prelude.Some(123);
var optionnone = Option<int>.None;

option.Should().BeSome();
option.Should().BeSome(8);
option.Should().BeSome(s => s.Should().Be(8));
option.Should().BeSome().Which.Should().Be(8);

optionnone.Should().BeNone();

Either, EitherAsync and EitherUnsafe

Methods

• Be(expected)
• BeLeft()
• BeLeft(action)
• BeRight()
• BeRight(action)
• BeBottom()

Example Usage

using FluentAssertions;
using FluentAssertions.LanguageExt;

... 
Either<int, string> left = Prelude.Left(8);
Either<int, string> right = Prelude.Right("a");

left.Should().BeLeft();
left.Should().BeLeft(l => l.Should().Be(8));
left.Should().BeLeft().Which.Should().Be(8);
left.Should().Be(8);

right.Should().BeRight();
right.Should().BeRight(r => r.Should().Be("a"));
right.Should().BeRight().Which.Should().Be("a");
right.Should().Be("a");

Validation

Breaking Change for 0.3.1

There's a breaking change when using BeFail() with the .Which extension.

When using the BeFail() assertion on a Validation<TFail, TSucc>, the .Which extension returns only a single failure instance even though the Validation type has a Seq<TFail>. This prevents proper assertions on the failures returned from a Validation using the .Which extension.

This has now been fixed.

The return signature for BeFail() has changed from AndWhichConstraint<LanguageExtValidationAssertions<TFail, TSuccess>, TFail> to AndWhichConstraint<LanguageExtValidationAssertions<TFail, TSuccess>, Seq<TFail>>

Methods

• BeFail()
• BeSuccess()
• BeSuccess(action)
• Be(expected)

Try and TryAsync

Methods

• BeFail()
• BeSuccess()

TryOption and TryAsyncOption

Methods

• BeFail()
• BeSome()
• BeSome(action)
• BeNone()
• BeNoneOrFail()
• Be(expected)

Fin

Methods

• BeSuccess()
• BeSuccess(action)
• BeFail()
• BeBottom()
• Be(expected)

Example Usage

using FluentAssertions;
using FluentAssertions.LanguageExt;

... 
Fin<int> successFin = Prelude.FinSucc(8);
Fin<int> failedFin = Prelude.FinFail<int>("Error message");

successFin.Should().BeSuccess();
successFin.Should().BeSuccess(v => v.Should().Be(8));
successFin.Should().BeSuccess().Which.Should().Be(8);
successFin.Should().Be(8);

failedFin.Should().BeFail();
failedFin.Should().BeFail().Which.Message.Should().Be("Error message");