[TomNaessens]

Adds Haskell examples for TESTed under tested/haskell/, one runnable Dodona exercise each, with tested/haskell/dirconfig.json setting the language. Each exercise shows one TESTed feature and is typical for the language; the exercises that one suite judges in every language (tested/echo-name, tested/smallest) are in #64.

Exercise	Shows
factorial	expression testing of a pure function (factorial :: Int -> Int)
sum-of-squares	a list argument, solved with map and foldr (sumOfSquares :: [Int] -> Int)
sum-lines	stdin/stdout with IO: interact reads numbers line by line and prints their sum

Descriptions in en and nl.

• TESTed adds module Submission where itself, so each description says not to start with a module line.
• The exercises use one-argument calls and no exit codes, so they avoid Problem with typing in Haskell universal-judge#568 (multi-argument integer calls) and Haskell: exitWith in main is caught as an exception, so the exit code is always 0 universal-judge#713 (exitWith).
• TESTed types DSL integers as Int (factorial 5 :: Int), so factorial is Int -> Int, not Integer. An empty list ([]) has no element type and makes TESTed reject the whole suite for Haskell, so sum-of-squares doesn't test it.

Part of https://github.com/dodona-edu/dodona/issues/8847.

Manual testing instructions

1. In a Dodona dev checkout with seeded data, check out this branch in the local clone of the example repository under data/exercises/ (git fetch && git checkout feature/8847-tested-haskell-examples).
2. Sign in as zeus (http://dodona.localhost:3000/dev_sign_in/1), open that repository's page and reprocess its activities.
3. Open the Haskell exercises ("Factorial", "Sum of squares", "Sum of lines") and submit each one's solution/solution.hs: all tests pass.
4. Edge case: in "Sum of squares", sum the numbers without squaring them: 3 of 4 tests fail.

Verification (dodona-authoring verify skill, ghcr.io/dodona-edu/dodona-tested, universal-judge master)

DSL validation passes for every suite. "en" and "nl" are full runs the way Dodona does them, with that natural_language.

Exercise	Reference solution	Wrong solution	en	nl
factorial	5/5 correct	rejected (compilation error: no factorial)	5/5	5/5
sum-of-squares	4/4 correct	rejected (compilation error: no sumOfSquares)	4/4	4/4
sum-lines	4/4 correct	rejected (4 wrong)	4/4	4/4

🤖 Generated with Claude Code