1 files changed, 128 insertions, 0 deletions
diff --git a/tests/runner.js b/tests/runner.js
new file mode 100644
index 0000000..bfafa10
--- /dev/null
+++ b/tests/runner.js
@@ -0,0 +1,128 @@
+/**
+ * Minimal in-browser test runner (no npm / no Node).
+ * Provides describe/it/assert and renders results into the document.
+ */
+(() => {
+  'use strict';
+
+  const suites = [];
+  let currentSuite = null;
+  const results = [];
+
+  /**
+   * @param {string} name
+   * @param {() => void} fn
+   */
+  function describe(name, fn) {
+    currentSuite = { name, tests: [] };
+    suites.push(currentSuite);
+    fn();
+    currentSuite = null;
+  }
+
+  /**
+   * @param {string} name
+   * @param {() => void|Promise<void>} fn
+   */
+  function it(name, fn) {
+    if (!currentSuite) throw new Error('it() outside describe()');
+    currentSuite.tests.push({ name, fn });
+  }
+
+  class AssertionError extends Error {}
+
+  /**
+   * @param {*} actual
+   * @param {*} expected
+   * @param {string} [message]
+   */
+  function assertEqual(actual, expected, message) {
+    const a = JSON.stringify(actual);
+    const b = JSON.stringify(expected);
+    if (a !== b) {
+      throw new AssertionError(message || `expected ${b}, got ${a}`);
+    }
+  }
+
+  /**
+   * @param {*} actual
+   * @param {string} [message]
+   */
+  function assertTrue(actual, message) {
+    if (actual !== true) {
+      throw new AssertionError(message || `expected true, got ${JSON.stringify(actual)}`);
+    }
+  }
+
+  /**
+   * @param {*} actual
+   * @param {string} [message]
+   */
+  function assertFalse(actual, message) {
+    if (actual !== false) {
+      throw new AssertionError(message || `expected false, got ${JSON.stringify(actual)}`);
+    }
+  }
+
+  /**
+   * @param {number} actual
+   * @param {number} expected
+   * @param {number} epsilon
+   * @param {string} [message]
+   */
+  function assertCloseTo(actual, expected, epsilon, message) {
+    if (Math.abs(actual - expected) > epsilon) {
+      throw new AssertionError(message || `expected ~${expected}, got ${actual}`);
+    }
+  }
+
+  /**
+   * @param {Function} fn
+   * @param {string} [message]
+   */
+  async function assertThrowsAsync(fn, message) {
+    try {
+      await fn();
+    } catch {
+      return;
+    }
+    throw new AssertionError(message || 'expected function to throw');
+  }
+
+  async function run() {
+    const root = document.getElementById('results');
+    const summary = document.getElementById('summary');
+    let passed = 0;
+    let failed = 0;
+
+    for (const suite of suites) {
+      const suiteEl = document.createElement('section');
+      const heading = document.createElement('h2');
+      heading.textContent = suite.name;
+      suiteEl.append(heading);
+
+      for (const test of suite.tests) {
+        const row = document.createElement('div');
+        row.className = 'test';
+        try {
+          await test.fn();
+          passed++;
+          row.classList.add('pass');
+          row.textContent = `✔ ${test.name}`;
+        } catch (error) {
+          failed++;
+          row.classList.add('fail');
+          row.textContent = `✘ ${test.name} — ${error && error.message ? error.message : String(error)}`;
+        }
+        suiteEl.append(row);
+      }
+      root.append(suiteEl);
+    }
+
+    summary.textContent = `${passed} passed, ${failed} failed`;
+    summary.className = failed === 0 ? 'all-pass' : 'has-failures';
+    document.title = failed === 0 ? 'PASS - Tests' : 'FAIL - Tests';
+  }
+
+  window.TestRunner = { describe, it, assertEqual, assertTrue, assertFalse, assertCloseTo, assertThrowsAsync, run };
+})();
+\ No newline at end of file