FsUnit.Expecto

I think that would be nice to have an alternative assertion syntax for Expecto as well. A lot of people, including myself, like use the FsUnit DSL for assertions.

Awesome, @kleidemos did most of the work to make it happened. https://gist.github.com/kleidemos/35af85db392f21eaedc095b50c3c9449 The only missing piece is to decide how to merge it into FsUnit.

I see three option, ordered by my current preference.

Option 1 (FsUnitTyped-like syntax, no NuGet package)

Pros:

• Type-safe assertions
• Backward compatibility with tests written using FsUnitTyped - http://fsprojects.github.io/FsUnit/FsUnitTyped.html#What-is-FsUnitTyped

Cons:

• Limited support for Expecto Expect module
• No message parameter in operator
• No NuGet package

Option 2 (FsUnit-like syntax, release on NuGet)

Pros:

• Backward compatibility tests with written using FsUnit - http://fsprojects.github.io/FsUnit/operators.html
• NuGet package

Cons:

• Limited support for Expecto Expect module
• No message parameter in operator
• Not type-safe

Option 3 (new syntax adapted for Expecto)

Pros:

• Better support of Expecto capabilities
• message parameter in operator
• NuGet package

Cons:

• No compatibility with existing FsUnit implementations

What is the right way to go?

[atlemann]

Doesn’t Expecto already have something similar to Option 1, which can be enabled by adding open Expecto.Flip in your test file. (https://github.com/haf/expecto/blob/master/Expecto/Flip.Expect.fs). I have never used the FsUnitTyped syntax before, only FsUnit syntax. To differentiate FsUnit.Expecto from Expecto.Flip, maybe Option 2 or 3 would be best?

[sergey-tihon]

Ok, I think that these are not enough reasons to compete with Flip.Expect