Add test generator (#325)

Extra test cases may be supplied using
`.meta/additional-test-cases.json`.

Each exercise's `.meta/test_generator.py` defines `gen_case`, and
optionally `test_name`, `HEADER` and `sort_key`.

Generators are added for 63 exercises.

The generated tests are identical to the existing tests, except with
- affine-cipher
- connect
- wordy

Python style is enforced by ruff, run by pre-commit and a new
pre-commit workflow.

I used Claude for this PR.

Author: keiravillekode

.github/workflows/pre-commit.yml

@@ -0,0 +1,18 @@
+name: Pre-commit checks
+on:
+  pull_request:
+    branches:
+      - main
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  pre-commit:
+    name: Pre-commit checks
+    runs-on: ubuntu-26.04
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1
+      - uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97
+      - uses: pre-commit/action@2c7b3805fd2a0fd8c1884dcaebf91fc102a13ecd

.gitignore

@@ -3,3 +3,6 @@
 bin/configlet
 bin/configlet.exe
 temp/
+
+__pycache__/
+*.pyc

.pre-commit-config.yaml

@@ -0,0 +1,24 @@
+exclude: |
+    (?x)^(
+        exercises/practice/.*/.docs/introduction.md|
+        exercises/practice/.*/.docs/instructions.md|
+        exercises/practice/.*/.*/.*\.v|
+        .github/CODEOWNERS|
+        .github/labels.yml|
+        bin/fetch-configlet
+    )$
+
+repos:
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v6.0.0
+    hooks:
+    -   id: trailing-whitespace
+    -   id: end-of-file-fixer
+    -   id: check-yaml
+    -   id: check-added-large-files
+-   repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.16.9
+    hooks:
+    -   id: ruff-check
+        args: [--fix]
+    -   id: ruff-format

.ruff.toml

@@ -0,0 +1 @@
+target-version = "py314"

README.md

@@ -72,7 +72,7 @@ A good place to start in the docs is to understand how the [Hello World](https:/
 
 #### How to implement a new exercise from start to finish
 
-There are two ways to implement a practice exercise. You can follow all the 13 steps listed below from start to finish, or you can run `./bin/bootstrap_practice_exercise.sh [SLUG]` to create all the files and folders you'll need. This will allow you to skip a few steps and jump right into writing your example solution, but you'll need [bash](https://www.gnu.org/software/bash/) and [jq](https://stedolan.github.io/jq/) to run the script.
+There are two ways to implement a practice exercise. You can follow all the 14 steps listed below from start to finish, or you can run `./bin/bootstrap_practice_exercise.sh [SLUG]` to create all the files and folders you'll need. This will allow you to skip a few steps and jump right into writing your example solution, but you'll need [bash](https://www.gnu.org/software/bash/) and [jq](https://stedolan.github.io/jq/) to run the script.
 
 1. Pick an exercise from the [problem-specifications](https://github.com/exercism/problem-specifications/tree/main/exercises) repo.
 2. Create a new entry for the exercise in [config.json](./config.json). Include
@@ -85,22 +85,23 @@ There are two ways to implement a practice exercise. You can follow all the 13 s
   - `bin/configlet sync --update --yes --docs --metadata --exercise [SLUG]`
   - `bin/configlet sync --update --tests include --exercise [SLUG]`
 4. Create 3 files in the new directory (located at `exercises/practice/[SLUG]`):
-  - `run_test.v`
   - `[SLUG].v`
   - `.meta/example.v`
+  - `.meta/test_generator.py`
 5. Write an example implementation in `[SLUG].v`
-6. Write a test suite in `run_test.v` based on the canonical data in [problem-specifications](https://github.com/exercism/problem-specifications/tree/main/exercises). Here's an example of [canonical data](https://github.com/exercism/problem-specifications/blob/main/exercises/grade-school/canonical-data.json) and here's the [corresponding test suite](./exercises/practice/grade-school/run_test.v).
-7. Run the test suite with `v -stats test run_test.v`
-8. Once all tests pass, make sure code is formatted properly with `v fmt -w [V_FILE]` on all the v files (example and test files)
-9. Copypaste everything in `[SLUG].v` into `.meta/example.v`
-10. Remove everything from `[SLUG].v` except the stub of the needed function, the `module main` at the top, and make a stub of a struct or two.
-11. Add needed info to the `...[SLUG]/.meta/config.json` file:
+6. Write a test generator in `.meta/test_generator.py`. It will receive the canonical data in [problem-specifications](https://github.com/exercism/problem-specifications/tree/main/exercises). Here's an example of [canonical data](https://github.com/exercism/problem-specifications/blob/main/exercises/grade-school/canonical-data.json).
+7. Generate `run_test.v` by running `generators/generate.py [SLUG]`
+8. Run the test suite with `v -stats test run_test.v`
+9. Once all tests pass, make sure code is formatted properly with `v fmt -w [V_FILE]` on all the v files (example and test files)
+10. Copypaste everything in `[SLUG].v` into `.meta/example.v`
+11. Remove everything from `[SLUG].v` except the stub of the needed function, the `module main` at the top, and make a stub of a struct or two.
+12. Add needed info to the `...[SLUG]/.meta/config.json` file:
   - Author's GitHub username
   - solution file name (should be `[SLUG].v`)
   - test file name (should be `run_test.v`)
   - example solution file name (should be `.meta/example.v`)
-12. Commit changes with [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/)
-13. Make your PR and do a little happy dance
+13. Commit changes with [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/)
+14. Make your PR and do a little happy dance
 
 ![](https://media3.giphy.com/media/ghVtt3BfMwYhi/giphy.gif?cid=790b7611a39608242e7ad1acf94c07788cdcada74ca02528&rid=giphy.gif&ct=g)
 

bin/bootstrap_practice_exercise.sh

@@ -16,14 +16,19 @@ exercise_dir="exercises/practice/${SLUG}"
 echo "Fetching latest version of configlet..."
 ./bin/fetch-configlet
 
-if [[ -z $author ]]; then
+if [[ -z ${author:-} ]]; then
     echo
     read -rp "What's your github username? " author
 fi
 
 bin/configlet create --practice-exercise $SLUG --author "${author}" --difficulty 5
 
-# Create V files
+# Create V files and the test generator
 touch $exercise_dir/.meta/example.v
 touch $exercise_dir/$SLUG.v
-touch $exercise_dir/run_test.v
+cat > $exercise_dir/.meta/test_generator.py <<'EOF'
+# Returns the body of the test function for one case of the canonical data.
+# Helpers for rendering V values and assertions are in generators/lib.py.
+def gen_case(case):
+    raise NotImplementedError("write gen_case for this exercise")
+EOF

bin/test

@@ -2,8 +2,8 @@
 
 # Synopsis:
 # Test the track's exercises.
-# 
-# At a minimum, this file must check if the example/exemplar solution of each 
+#
+# At a minimum, this file must check if the example/exemplar solution of each
 # Practice/Concept Exercise passes the exercise's tests.
 #
 # To check this, you usually have to (temporarily) replace the exercise's solution files

docs/INSTALLATION.md

@@ -6,4 +6,4 @@ Please follow the [instructions in the official documentation](https://github.co
 It is highly recommended that you install from source and then follow the [instructions on symlinking](https://github.com/vlang/v/blob/master/README.md#symlinking) to be able to run V anywhere.
 
 ## Using an IDE
-The best way to use V in an IDE is to use the [VSCodium](https://vscodium.com/) [extension](https://marketplace.visualstudio.com/items?itemName=vlanguage.vscode-vlang). There is also support for [Vim](https://github.com/ollykel/v-vim), [Emacs](https://github.com/damon-kwok/v-mode), and [Sublime](https://github.com/elliotchance/vlang-sublime). To see a full list of supported IDEs, see the [V homepage](https://vlang.io/).
+The best way to use V in an IDE is to use the [VSCodium](https://vscodium.com/) [extension](https://marketplace.visualstudio.com/items?itemName=vlanguage.vscode-vlang). There is also support for [Vim](https://github.com/ollykel/v-vim), [Emacs](https://github.com/damon-kwok/v-mode), and [Sublime](https://github.com/elliotchance/vlang-sublime). To see a full list of supported IDEs, see the [V homepage](https://vlang.io/).

docs/TESTS.md

@@ -8,4 +8,4 @@ To run tests for a specific implementation of an exercise, here are the recommen
 1. run `v -stats test run_test.v`
 
 ## Testing in V
-For more information on testing in V, refer to the [official docs](https://github.com/vlang/v/blob/master/doc/docs.md#testing)
+For more information on testing in V, refer to the [official docs](https://github.com/vlang/v/blob/master/doc/docs.md#testing)

exercises/practice/acronym/.meta/test_generator.py

@@ -0,0 +1,8 @@
+from lib import assert_eq, v_string
+
+
+def gen_case(case):
+    return [
+        f"phrase := {v_string(case['input']['phrase'])}",
+        assert_eq("abbreviate(phrase)", v_string(case["expected"])),
+    ]