diff --git a/packages/thumbnail-handler/package.json b/packages/thumbnail-handler/package.json
index 9dbcb53bb..f782a7c29 100644
--- a/packages/thumbnail-handler/package.json
+++ b/packages/thumbnail-handler/package.json
@@ -17,7 +17,8 @@
   "devDependencies": {
     "chai": "^4.3.6",
     "eslint-plugin-prettier": "^4.0.0",
-    "mocha": "^10.0.0"
+    "mocha": "^10.0.0",
+    "nock": "^13.3.1"
   },
   "dependencies": {
     "@google-cloud/functions-framework": "3.1.2",
diff --git a/packages/thumbnail-handler/src/index.ts b/packages/thumbnail-handler/src/index.ts
index bd7b68d01..8ce56ad33 100644
--- a/packages/thumbnail-handler/src/index.ts
+++ b/packages/thumbnail-handler/src/index.ts
@@ -158,8 +158,10 @@ const getImageSize = async (url: string): Promise<[number, number] | null> => {
   }
 }
 
-// credit to https://github.com/reddit-archive/reddit/blob/753b17407e9a9dca09558526805922de24133d53/r2/r2/lib/media.py#L706
-const findThumbnail = async (content: string): Promise<string | null> => {
+// credit: https://github.com/reddit-archive/reddit/blob/753b17407e9a9dca09558526805922de24133d53/r2/r2/lib/media.py#L706
+export const findThumbnail = async (
+  content: string
+): Promise<string | null> => {
   const dom = parseHTML(content).document
 
   // find the largest and squarest image as the thumbnail
diff --git a/packages/thumbnail-handler/test/fixtures/findThumbnail.html b/packages/thumbnail-handler/test/fixtures/findThumbnail.html
new file mode 100644
index 000000000..66192deac
--- /dev/null
+++ b/packages/thumbnail-handler/test/fixtures/findThumbnail.html
@@ -0,0 +1,9 @@
+<DIV class="page" id="readability-page-1">
+    <img src="https://omnivore.app/small.png" alt="small image" />
+
+    <img src="https://omnivore.app/large_and_square.png" alt="large and square image" />
+
+    <img src="https://omnivore.app/wide.png" alt="wide image" />
+
+    <img src="https://omnivore.app/sprite.png" alt="sprite image" />
+</DIV>
diff --git a/packages/thumbnail-handler/test/fixtures/large_and_square.png b/packages/thumbnail-handler/test/fixtures/large_and_square.png
new file mode 100644
index 000000000..4c4992af7
Binary files /dev/null and b/packages/thumbnail-handler/test/fixtures/large_and_square.png differ
diff --git a/packages/thumbnail-handler/test/fixtures/small.png b/packages/thumbnail-handler/test/fixtures/small.png
new file mode 100644
index 000000000..930657193
Binary files /dev/null and b/packages/thumbnail-handler/test/fixtures/small.png differ
diff --git a/packages/thumbnail-handler/test/fixtures/sprite.png b/packages/thumbnail-handler/test/fixtures/sprite.png
new file mode 100644
index 000000000..4c4992af7
Binary files /dev/null and b/packages/thumbnail-handler/test/fixtures/sprite.png differ
diff --git a/packages/thumbnail-handler/test/fixtures/wide.png b/packages/thumbnail-handler/test/fixtures/wide.png
new file mode 100644
index 000000000..232acac91
Binary files /dev/null and b/packages/thumbnail-handler/test/fixtures/wide.png differ
diff --git a/packages/thumbnail-handler/test/index.test.ts b/packages/thumbnail-handler/test/index.test.ts
new file mode 100644
index 000000000..575cfc87d
--- /dev/null
+++ b/packages/thumbnail-handler/test/index.test.ts
@@ -0,0 +1,30 @@
+import { expect } from 'chai'
+import fs from 'fs'
+import 'mocha'
+import nock from 'nock'
+import path from 'path'
+import { findThumbnail } from '../src'
+
+describe('findThumbnail', () => {
+  it('finds the largest and squarest image', async () => {
+    const images = ['large_and_square', 'small', 'sprite', 'wide']
+    // mock getting image by url
+    images.forEach((image) => {
+      nock('https://omnivore.app')
+        .get(`/${image}.png`)
+        .replyWithFile(200, path.join(__dirname, 'fixtures', `${image}.png`))
+    })
+    // get html content from file
+    const content = fs.readFileSync(
+      path.join(__dirname, 'fixtures', 'findThumbnail.html'),
+      'utf8'
+    )
+    // find thumbnail
+    const thumbnail = await findThumbnail(content)
+
+    expect(thumbnail).to.eql('https://omnivore.app/large_and_square.png')
+
+    // clean up
+    nock.cleanAll()
+  })
+})
diff --git a/packages/thumbnail-handler/test/stub.test.ts b/packages/thumbnail-handler/test/stub.test.ts
deleted file mode 100644
index 24ad25c8f..000000000
--- a/packages/thumbnail-handler/test/stub.test.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-import 'mocha'
-import { expect } from 'chai'
-
-describe('stub test', () => {
-  it('should pass', () => {
-    expect(true).to.be.true
-  })
-})