Verify exercises in docker (#478)

Limits the number of parallel-letter-frequency processes

Author: keiravillekode

bin/verify-exercises-in-docker

@@ -0,0 +1,91 @@
+#!/usr/bin/env bash
+
+# Synopsis:
+# Verify that each exercise's example/exemplar solution passes the tests
+# using the track's test runner Docker image.
+# You can either verify all exercises or a single exercise.
+
+# Example: verify all exercises in Docker
+# bin/verify-exercises-in-docker
+
+# Example: verify single exercise in Docker
+# bin/verify-exercises-in-docker two-fer
+
+set -eo pipefail
+
+die() { echo "$*" >&2; exit 1; }
+
+required_tool() {
+    command -v "${1}" >/dev/null 2>&1 ||
+        die "${1} is required but not installed. Please install it and make sure it's in your PATH."
+}
+
+required_tool docker
+
+copy_example_or_examplar_to_solution() {
+    jq -c '[.files.solution, .files.exemplar // .files.example] | transpose | map({src: .[1], dst: .[0]}) | .[]' .meta/config.json \
+    | while read -r src_and_dst; do
+        cp "$(jq -r '.src' <<< "${src_and_dst}")" "$(jq -r '.dst' <<< "${src_and_dst}")"
+    done
+}
+
+pull_docker_image() {
+    docker pull exercism/emacs-lisp-test-runner ||
+        die $'Could not find the `exercism/emacs-lisp-test-runner` Docker image.\nCheck the test runner docs at https://exercism.org/docs/building/tooling/test-runners for more information.'
+}
+
+run_tests() {
+    local slug
+    slug="${1}"
+
+    docker run \
+        --rm \
+        --network none \
+        --read-only \
+        --mount type=bind,src="${PWD}",dst=/solution \
+        --mount type=bind,src="${PWD}",dst=/output \
+        --mount type=tmpfs,dst=/tmp \
+        exercism/emacs-lisp-test-runner "${slug}" /solution /output
+    jq -re '.message // .status' "${PWD}/results.json"
+    jq -e '.status == "pass"' "${PWD}/results.json" >/dev/null 2>&1
+}
+
+verify_exercise() {
+    local dir
+    local slug
+    local tmp_dir
+    dir=$(realpath "${1}")
+    slug=$(basename "${dir}")
+    tmp_dir=$(mktemp -d -t "exercism-verify-${slug}-XXXXX")
+
+    echo "Verifying ${slug} exercise..."
+
+    (
+        trap 'rm -rf "$tmp_dir"' EXIT    # remove tempdir when subshell ends
+        cp -r "${dir}/." "${tmp_dir}"
+        cd "${tmp_dir}"
+
+        copy_example_or_examplar_to_solution
+        run_tests "${slug}"
+    )
+}
+
+verify_exercises() {
+    local exercise_slug
+    exercise_slug="${1}"
+
+    shopt -s nullglob
+    count=0
+    for exercise_dir in ./exercises/{concept,practice}/${exercise_slug}/; do
+        if [[ -d "${exercise_dir}" ]]; then
+            verify_exercise "${exercise_dir}"
+            ((++count))
+        fi
+    done
+    ((count > 0)) || die 'no matching exercises found!'
+}
+
+pull_docker_image
+
+exercise_slug="${1:-*}"
+verify_exercises "${exercise_slug}"

exercises/practice/parallel-letter-frequency/.meta/example.el

@@ -24,7 +24,7 @@
     (let ((cleaned-texts (mapcar #'clean-text texts)))
     (if (cl-every #'string-empty-p cleaned-texts)
         (make-hash-table :test 'equal)
-      (let* ((num-processes (min (length cleaned-texts) (max 1 (string-to-number (shell-command-to-string "nproc")))))
+      (let* ((num-processes (min (length cleaned-texts) 8 (max 1 (string-to-number (shell-command-to-string "nproc")))))
              (texts-per-process (ceiling (/ (float (length cleaned-texts)) num-processes)))
              (results (make-hash-table :test 'equal))
              (pending num-processes)