diff --git a/src/controllers/write/topics.js b/src/controllers/write/topics.js
index df80991cb1..7c08574699 100644
--- a/src/controllers/write/topics.js
+++ b/src/controllers/write/topics.js
@@ -94,27 +94,20 @@ Topics.getThumbs = async (req, res) => {
 	helpers.formatApiResponse(200, res, await topics.thumbs.get(req.params.tid));
 };
 
-Topics.addThumb = async (req, res) => {
+Topics.addThumb = async (req, res, next) => {
 	await checkThumbPrivileges({ tid: req.params.tid, uid: req.user.uid, res });
 	if (res.headersSent) {
 		return;
 	}
 
-	/**
-	 * todo test:
-	 *   - uuid
-	 *   - tid
-	 *   - number but not tid
-	 *   - random garbage
-	 *   - wrong caller uid (unpriv)
-	 */
-
-	const files = await uploadsController.uploadThumb(req, res);	// response is handled here, fix this?
+	const files = await uploadsController.uploadThumb(req, res, next);	// response is handled here, fix this?
 
 	// Add uploaded files to topic zset
-	await Promise.all(files.map(async (fileObj) => {
-		await topics.thumbs.associate(req.params.tid, fileObj.path);
-	}));
+	if (files && files.length) {
+		await Promise.all(files.map(async (fileObj) => {
+			await topics.thumbs.associate(req.params.tid, fileObj.path);
+		}));
+	}
 };
 
 Topics.migrateThumbs = async (req, res) => {
diff --git a/src/topics/thumbs.js b/src/topics/thumbs.js
index 1b15441486..d702b65167 100644
--- a/src/topics/thumbs.js
+++ b/src/topics/thumbs.js
@@ -54,7 +54,6 @@ Thumbs.migrate = async function (uuid, id) {
 };
 
 Thumbs.delete = async function (id, relativePath) {
-	// TODO: tests
 	const isDraft = validator.isUUID(String(id));
 	const set = `${isDraft ? 'draft' : 'topic'}:${id}:thumbs`;
 	const absolutePath = path.join(nconf.get('upload_path'), relativePath);
diff --git a/test/topics/thumbs.js b/test/topics/thumbs.js
new file mode 100644
index 0000000000..9be6d9eb28
--- /dev/null
+++ b/test/topics/thumbs.js
@@ -0,0 +1,190 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const assert = require('assert');
+const nconf = require('nconf');
+const request = require('request-promise-native');
+
+var db = require('../mocks/databasemock');
+
+const meta = require('../../src/meta');
+const user = require('../../src/user');
+const groups = require('../../src/groups');
+const topics = require('../../src/topics');
+const categories = require('../../src/categories');
+const file = require('../../src/file');
+const utils = require('../../src/utils');
+
+const helpers = require('../helpers');
+
+describe('Topic thumbs', () => {
+	let topicObj;
+	let categoryObj;
+	let adminUid;
+	let adminJar;
+	let adminCSRF;
+	let fooJar;
+	let fooCSRF;
+	let fooUid;
+	const thumbPaths = ['files/test.png', 'files/test2.png'];
+	const uuid = utils.generateUUID();
+
+	function createFiles() {
+		fs.closeSync(fs.openSync(path.resolve(__dirname, '../uploads', thumbPaths[0]), 'w'));
+		fs.closeSync(fs.openSync(path.resolve(__dirname, '../uploads', thumbPaths[1]), 'w'));
+	}
+
+	before(async () => {
+		meta.config.allowTopicsThumbnail = 1;
+
+		adminUid = await user.create({ username: 'admin', password: '123456' });
+		fooUid = await user.create({ username: 'foo', password: '123456' });
+		await groups.join('administrators', adminUid);
+		({ adminJar, adminCSRF } = await new Promise((resolve, reject) => {
+			helpers.loginUser('admin', '123456', (err, adminJar, adminCSRF) => {
+				if (err) {
+					return reject(err);
+				}
+
+				resolve({ adminJar, adminCSRF });
+			});
+		}));
+		({ fooJar, fooCSRF } = await new Promise((resolve, reject) => {
+			helpers.loginUser('foo', '123456', (err, fooJar, fooCSRF) => {
+				if (err) {
+					return reject(err);
+				}
+
+				resolve({ fooJar, fooCSRF });
+			});
+		}));
+
+		categoryObj = await categories.create({
+			name: 'Test Category',
+			description: 'Test category created by testing script',
+		});
+		topicObj = await topics.post({
+			uid: adminUid,
+			cid: categoryObj.cid,
+			title: 'Test Topic Title',
+			content: 'The content of test topic',
+		});
+
+		// Touch a couple files and associate it to a topic
+		createFiles();
+		db.sortedSetAdd(`topic:${topicObj.tid}:thumbs`, 0, `/${thumbPaths[0]}`);
+	});
+
+	it('should return bool for whether a thumb exists', async () => {
+		const exists = await topics.thumbs.exists(topicObj.tid, `/${thumbPaths[0]}`);
+		assert.strictEqual(exists, true);
+	});
+
+	describe('.get()', () => {
+		it('should return an array of thumbs', async () => {
+			const thumbs = await topics.thumbs.get(topicObj.tid);
+			assert.deepStrictEqual(thumbs, [{ url: `${nconf.get('upload_url')}/${thumbPaths[0]}` }]);
+		});
+
+		it('should return an array of an array of thumbs if multiple tids are passed in', async () => {
+			const thumbs = await topics.thumbs.get([topicObj.tid, topicObj.tid + 1]);
+			assert.deepStrictEqual(thumbs, [
+				[{ url: `${nconf.get('upload_url')}/${thumbPaths[0]}` }],
+				[],
+			]);
+		});
+	});
+
+	describe('.associate()', () => {
+		it('should add an uploaded file to a zset', async () => {
+			await topics.thumbs.associate(2, thumbPaths[0]);
+
+			const exists = await db.isSortedSetMember(`topic:2:thumbs`, thumbPaths[0]);
+			assert(exists);
+		});
+
+		it('should also work with UUIDs', async () => {
+			await topics.thumbs.associate(uuid, thumbPaths[1]);
+
+			const exists = await db.isSortedSetMember(`draft:${uuid}:thumbs`, thumbPaths[1]);
+			assert(exists);
+		});
+	});
+
+	describe('.migrate()', () => {
+		it('should combine the thumbs uploaded to a UUID zset and combine it with a topic\'s thumb zset', async () => {
+			await topics.thumbs.migrate(uuid, 2);
+
+			const thumbs = await topics.thumbs.get(2);
+			assert.strictEqual(thumbs.length, 2);
+			assert.deepStrictEqual(thumbs, [
+				{ url: `${nconf.get('upload_url')}/${thumbPaths[0]}` },
+				{ url: `${nconf.get('upload_url')}/${thumbPaths[1]}` },
+			]);
+		});
+	});
+
+	describe(`.delete()`, () => {
+		it('should remove a file from sorted set AND disk', async () => {
+			await topics.thumbs.delete(1, thumbPaths[0]);
+
+			assert.strictEqual(await db.isSortedSetMember('topic:1:thumbs', thumbPaths[0]), false);
+			assert.strictEqual(await file.exists(`${nconf.get('upload_path')}/${thumbPaths[0]}`), false);
+		});
+
+		it('should also work with UUIDs', async () => {
+			await topics.thumbs.associate(uuid, thumbPaths[1]);
+			await topics.thumbs.delete(uuid, thumbPaths[1]);
+
+			assert.strictEqual(await db.isSortedSetMember(`draft:${uuid}:thumbs`, thumbPaths[1]), false);
+			assert.strictEqual(await file.exists(`${nconf.get('upload_path')}/${thumbPaths[1]}`), false);
+		});
+	});
+
+	describe('HTTP calls to topic thumb routes', () => {
+		before(() => {
+			createFiles();
+		});
+
+		it('should succeed with a valid tid', (done) => {
+			helpers.uploadFile(`${nconf.get('url')}/api/v3/topics/1/thumbs`, path.join(__dirname, '../files/test.png'), {}, adminJar, adminCSRF, function (err, res, body) {
+				assert.ifError(err);
+				assert.strictEqual(res.statusCode, 200);
+				done();
+			});
+		});
+
+		it('should succeed with a uuid', (done) => {
+			helpers.uploadFile(`${nconf.get('url')}/api/v3/topics/${uuid}/thumbs`, path.join(__dirname, '../files/test.png'), {}, adminJar, adminCSRF, function (err, res, body) {
+				assert.ifError(err);
+				assert.strictEqual(res.statusCode, 200);
+				done();
+			});
+		});
+
+		it('should fail with a non-existant tid', (done) => {
+			helpers.uploadFile(`${nconf.get('url')}/api/v3/topics/2/thumbs`, path.join(__dirname, '../files/test.png'), {}, adminJar, adminCSRF, function (err, res, body) {
+				assert.ifError(err);
+				assert.strictEqual(res.statusCode, 404);
+				done();
+			});
+		});
+
+		it('should fail when garbage is passed in', (done) => {
+			helpers.uploadFile(`${nconf.get('url')}/api/v3/topics/abracadabra/thumbs`, path.join(__dirname, '../files/test.png'), {}, adminJar, adminCSRF, function (err, res, body) {
+				assert.ifError(err);
+				assert.strictEqual(res.statusCode, 404);
+				done();
+			});
+		});
+
+		it('should fail when calling user cannot edit the tid', (done) => {
+			helpers.uploadFile(`${nconf.get('url')}/api/v3/topics/1/thumbs`, path.join(__dirname, '../files/test.png'), {}, fooJar, fooCSRF, function (err, res, body) {
+				assert.ifError(err);
+				assert.strictEqual(res.statusCode, 403);
+				done();
+			});
+		});
+	});
+});