From a2aaa55b89a582afa64df051df0b8decbe4f4943 Mon Sep 17 00:00:00 2001
From: Alex Gleason <alex@alexgleason.me>
Date: Wed, 26 Feb 2025 15:09:01 -0600
Subject: [PATCH] Add tests to captcha modules

---
 packages/captcha/assets.test.ts   |  9 +++++++++
 packages/captcha/canvas.test.ts   | 22 ++++++++++++++++++++++
 packages/captcha/captcha.test.ts  | 12 ++++++++++++
 packages/captcha/geometry.test.ts |  8 ++++++++
 packages/captcha/geometry.ts      |  9 +++++++--
 5 files changed, 58 insertions(+), 2 deletions(-)
 create mode 100644 packages/captcha/assets.test.ts
 create mode 100644 packages/captcha/canvas.test.ts
 create mode 100644 packages/captcha/captcha.test.ts
 create mode 100644 packages/captcha/geometry.test.ts

diff --git a/packages/captcha/assets.test.ts b/packages/captcha/assets.test.ts
new file mode 100644
index 00000000..c86eb203
--- /dev/null
+++ b/packages/captcha/assets.test.ts
@@ -0,0 +1,9 @@
+import { assert } from '@std/assert';
+
+import { getCaptchaImages } from './assets.ts';
+
+Deno.test('getCaptchaImages', async () => {
+  // If this function runs at all, it most likely worked.
+  const { bgImages } = await getCaptchaImages();
+  assert(bgImages.length);
+});
diff --git a/packages/captcha/canvas.test.ts b/packages/captcha/canvas.test.ts
new file mode 100644
index 00000000..6e066a1d
--- /dev/null
+++ b/packages/captcha/canvas.test.ts
@@ -0,0 +1,22 @@
+import { createCanvas } from '@gfx/canvas-wasm';
+import { assertNotEquals } from '@std/assert';
+import { encodeHex } from '@std/encoding/hex';
+
+import { addNoise } from './canvas.ts';
+
+// This is almost impossible to truly test,
+// but we can at least check that the image on the canvas changes.
+Deno.test('addNoise', async () => {
+  const canvas = createCanvas(100, 100);
+  const ctx = canvas.getContext('2d');
+
+  const dataBefore = ctx.getImageData(0, 0, canvas.width, canvas.height);
+  const hashBefore = await crypto.subtle.digest('SHA-256', dataBefore.data);
+
+  addNoise(ctx, canvas.width, canvas.height);
+
+  const dataAfter = ctx.getImageData(0, 0, canvas.width, canvas.height);
+  const hashAfter = await crypto.subtle.digest('SHA-256', dataAfter.data);
+
+  assertNotEquals(encodeHex(hashBefore), encodeHex(hashAfter));
+});
diff --git a/packages/captcha/captcha.test.ts b/packages/captcha/captcha.test.ts
new file mode 100644
index 00000000..285adae7
--- /dev/null
+++ b/packages/captcha/captcha.test.ts
@@ -0,0 +1,12 @@
+import { getCaptchaImages } from './assets.ts';
+import { generateCaptcha, verifyCaptchaSolution } from './captcha.ts';
+
+Deno.test('generateCaptcha', async () => {
+  const images = await getCaptchaImages();
+  generateCaptcha(images, { w: 370, h: 400 }, { w: 65, h: 65 });
+});
+
+Deno.test('verifyCaptchaSolution', () => {
+  verifyCaptchaSolution({ w: 65, h: 65 }, { x: 0, y: 0 }, { x: 0, y: 0 });
+  verifyCaptchaSolution({ w: 65, h: 65 }, { x: 0, y: 0 }, { x: 10, y: 10 });
+});
diff --git a/packages/captcha/geometry.test.ts b/packages/captcha/geometry.test.ts
new file mode 100644
index 00000000..057ebf3d
--- /dev/null
+++ b/packages/captcha/geometry.test.ts
@@ -0,0 +1,8 @@
+import { assertEquals } from '@std/assert';
+
+import { areIntersecting } from './geometry.ts';
+
+Deno.test('areIntersecting', () => {
+  assertEquals(areIntersecting({ x: 0, y: 0, w: 10, h: 10 }, { x: 5, y: 5, w: 10, h: 10 }), true);
+  assertEquals(areIntersecting({ x: 0, y: 0, w: 10, h: 10 }, { x: 15, y: 15, w: 10, h: 10 }), false);
+});
diff --git a/packages/captcha/geometry.ts b/packages/captcha/geometry.ts
index b1993e0b..40e5f2fd 100644
--- a/packages/captcha/geometry.ts
+++ b/packages/captcha/geometry.ts
@@ -8,15 +8,20 @@ export interface Dimensions {
   h: number;
 }
 
-export type Rectangle = Point & Dimensions;
+type Rectangle = Point & Dimensions;
 
+/** Check if the two rectangles intersect by at least `threshold` percent. */
 export function areIntersecting(rect1: Rectangle, rect2: Rectangle, threshold = 0.5): boolean {
   const r1cx = rect1.x + rect1.w / 2;
   const r2cx = rect2.x + rect2.w / 2;
+
   const r1cy = rect1.y + rect1.h / 2;
   const r2cy = rect2.y + rect2.h / 2;
+
   const dist = Math.sqrt((r2cx - r1cx) ** 2 + (r2cy - r1cy) ** 2);
+
   const e1 = Math.sqrt(rect1.h ** 2 + rect1.w ** 2) / 2;
   const e2 = Math.sqrt(rect2.h ** 2 + rect2.w ** 2) / 2;
-  return dist < (e1 + e2) * threshold;
+
+  return dist <= (e1 + e2) * threshold;
 }