write-tests

name	write-tests
description	Write or update tests for a module or feature in yopl. Use when asked to write tests, add coverage, or verify functionality.

Write Tests for yopl

Write or update tests for the yopl library.

Steps

1. Identify the module or feature to test. Read its source under src/ to understand the public API.
2. Choose the appropriate test file:
   • tests/test-solve.js — default sync solver (src/solve.js)
   • tests/test-gen.js — generator solver (src/solvers/gen.js)
   • tests/test-async.js — async callback solver (src/solvers/async.js)
   • tests/test-asyncGen.js — async generator solver (src/solvers/asyncGen.js)
   • tests/test-rules.js — built-in rule libraries (logic, comp, math, bits)
   • tests/test-system.js — system rules
   • For an entirely new area, create tests/test-foo.js and wire it into tests/tests.js.
3. Add test functions to the exported array in the chosen file.
4. Run the suite: npm test.
5. Report results and any failures.

Test harness

Tests use a custom harness in tests/harness.js. Each test file imports submit and TEST, exports a default array of test functions:

import unify, {variable as v} from 'deep6/unify.js';
import assemble from 'deep6/traverse/assemble.js';
import solve from '../src/solve.js';
import {submit, TEST} from './harness.js';

export default [
  function test_my_feature() {
    const rules = {
      'one/1': () => [{args: [1]}]
    };
    const X = v('X');
    const result = [];
    solve(rules, 'one/1', [X], env => result.push(assemble(X, env)));
    eval(TEST('unify(result, [1])'));
  }
];

Conventions

• Import source modules with relative paths: import solve from '../src/solve.js';.
• Import {submit, TEST} from ./harness.js.
• Use eval(TEST('expression')) for assertions — the expression is both the test and the message.
• Name test functions test_descriptive_name.
• Test both success and failure cases (rules that succeed, rules that fail to unify, multi-solution backtracking).
• Use assemble(var, env) from deep6/traverse/assemble.js to extract bound values.
• For list-shaped data, use the makeList helper from tests/helpers.js.
• For async solvers, return a promise from the test or use the harness's async support.