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https://github.com/akshaymankar/polysemy-mocks

Mock polysemy effects
https://github.com/akshaymankar/polysemy-mocks

effects haskell haskell-library mock polysemy

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Mock polysemy effects

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# Polysemy Mocks

## Overview

`polysemy-mocks` aims to provide a structure to write all mocks for polysemy and to generate those.

## Example

```haskell
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}

module TeletypeSpec where

import Data.Kind
import Polysemy
import Polysemy.Internal (send)
import Test.Hspec
import Test.Polysemy.Mock
import Test.Polysemy.Mock.TH (genMock)
import Prelude hiding (read)

data Teletype (m :: Type -> Type) a where
Read :: Teletype m String
Write :: String -> Teletype m ()

makeSem ''Teletype

genMock ''Teletype

program :: Member Teletype r => Sem r ()
program = do
write "Name: "
name <- read
write $ "Hello " <> name

spec :: Spec
spec =
describe "program" $ do
it "greets" $ runM @IO . evalMock $ do
mockReadReturns (pure "Akshay")
mock @Teletype @IO program
writes <- mockWriteCalls
embed $ writes `shouldBe` ["Name: ", "Hello Akshay"]
```