CI: check exercises against test runner

.github/workflows/test-runner.yml

@@ -0,0 +1,18 @@
+name: Track Exercises on Runner
+
+on:
+  pull_request:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+jobs:
+  ci:
+    runs-on: ubuntu-24.04
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
+      - run: docker pull exercism/zig-test-runner
+      - name: Run tests for all exercises
+        run: sh ./bin/test

bin/.test-in-docker

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+
+# This script is meant to be run in the docker container of zig-test-runner
+
+all_slugs="$*"
+
+exit_code=0
+
+for slug in $all_slugs; do
+  snake="${slug//-/_}"
+  local_exit_code=0
+
+  rm -rf /tmp/solution
+  cp -r "/exercises/practice/${slug}" /tmp/solution
+
+  # Integration test: Check if the example solution passes the tests
+  # as run by the zig-test-runner similiarly to a student submitting
+  # their solution.
+  cp /tmp/solution/.meta/example.zig "/tmp/solution/${snake}.zig"
+  bin/run.sh "${slug}" /tmp/solution /tmp/solution > /dev/null
+  solution_pattern=$(cat /tmp/solution/results.json | jq -r tostring | grep "{\"version\":2,\"status\":\"pass\"")
+
+  errors=""
+
+  if [ -z "$solution_pattern" ]; then
+    errors="${errors}\n\nSolution is incorrect:\n$(cat /tmp/solution/results.json | jq -r '.message')"
+    local_exit_code=1;
+  fi
+
+  if [ $local_exit_code = 0 ]; then
+    echo -e "${slug}: \e[32mPASSED\e[0m"
+  else
+    exit_code=1
+    echo -e "${slug}: \e[31mFAILED\e[0m\n${errors}\n\n"
+  fi
+done
+
+exit ${exit_code}

bin/test

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+#!/usr/bin/env bash
+
+# Synopsis:
+# Test the zig track's exercises.
+#
+# For each exercise we test if the example solution
+# .meta/example.zig passes the tests.
+#
+# Usage:
+# ./bin/test [slug...]
+
+all_slugs="$*"
+if [ -z "$all_slugs" ]; then
+  all_slugs=$(ls ./exercises/practice/)
+fi
+
+docker run --rm --entrypoint bash \
+       --network none \
+       --mount type=bind,src="$(realpath ./exercises)",dst=/exercises,ro \
+       --mount type=bind,src="$(realpath ./bin)",dst=/scripts,ro \
+       --mount type=tmpfs,dst=/tmp \
+       exercism/zig-test-runner \
+       /scripts/.test-in-docker "$all_slugs"
+
+exit_code=$?
+
+exit ${exit_code}