diff --git a/tests/formDataServer.test.js b/tests/formDataServer.test.js
index 0ee1766..a9e2b2a 100644
--- a/tests/formDataServer.test.js
+++ b/tests/formDataServer.test.js
@@ -6,6 +6,7 @@ const fs = require('fs');
 const path = require('path');
 const axios = require('axios');
 const { Server, Agent } = require('http');
+const querystring = require('querystring');
 
 // this prevents `socket hang up` for Node.js 20.10+
 axios.defaults.httpAgent = new Agent({ keepAlive: false });
@@ -39,7 +40,18 @@ describe('Form Data Server', () => {
         server.close();
       });
 
-      it('should save data for valid expense on "POST /submit-expense" request', async () => {
+      it('should return an HTML form on "GET /" request', async () => {
+        const response = await axios.get(`${HOST}/`);
+
+        expect(response.status).toBe(200);
+        expect(response.headers['content-type']).toContain('text/html');
+        expect(response.data).toContain('<form');
+        expect(response.data).toContain('name="date"');
+        expect(response.data).toContain('name="title"');
+        expect(response.data).toContain('name="amount"');
+      });
+
+      it('should save data for valid expense on "POST /add-expense" request', async () => {
         fs.writeFileSync(dataPath, JSON.stringify({}));
 
         const expense = {
@@ -56,7 +68,7 @@ describe('Form Data Server', () => {
         expect(savedData).toStrictEqual(expense);
       });
 
-      it('should reject request without all params on "POST /submit-expense" request', async () => {
+      it('should reject request without all params on "POST /add-expense" request', async () => {
         fs.writeFileSync(dataPath, JSON.stringify({}));
 
         const expense = {
@@ -64,27 +76,38 @@ describe('Form Data Server', () => {
           amount: '100',
         };
 
-        expect.assertions(2);
+        expect.assertions(3);
 
         try {
           await axios.post(`${HOST}/add-expense`, expense);
         } catch (err) {
+          expect(err.response.status).toBe(400);
           expect(err.response.data.length).toBeGreaterThan(0);
 
           expect(JSON.parse(fs.readFileSync(dataPath))).toStrictEqual({});
         }
       });
 
-      it('should return JSON on "POST /submit-expense" request', async () => {
+      it('should return HTML with formatted JSON on "POST /add-expense" request', async () => {
         const expense = {
           date: '2024-01-25',
           title: 'Test Expense',
           amount: '100',
         };
-        const response = await axios.post(`${HOST}/add-expense`, expense);
-
-        expect(response.headers['content-type']).toBe('application/json');
-        expect(response.data).toStrictEqual(expense);
+        const response = await axios.post(
+          `${HOST}/add-expense`,
+          querystring.stringify(expense),
+          {
+            headers: {
+              'Content-Type': 'application/x-www-form-urlencoded',
+            },
+          },
+        );
+
+        expect(response.headers['content-type']).toContain('text/html');
+        expect(response.data).toContain('<html');
+        expect(response.data).toContain('<pre>');
+        expect(response.data).toContain(JSON.stringify(expense, null, 2));
       });
 
       it('should return 404 for invalid url', async () => {