VALIDATION-TEST-PLAN.md

Product Price & Quantity Validation Test Plan

Changes Summary

Backend Changes (routes/products.js)

POST /api/products Endpoint

• Already had correct validation:
  • Price validation: isNaN(price) || price <= 0 → Error: "Price must be a positive number"
  • Quantity validation: isNaN(quantity) || quantity < 1 → Error: "Quantity must be a positive integer"

PATCH /api/products/:id Endpoint

• BEFORE:

  • Price: Error message was "Price must be positive" (imprecise)
  • Quantity allowed 0: quantity < 0 (incorrect, zero should be invalid)

• AFTER:

  • Price error message updated to: "Price must be a positive number" (consistent with POST)
  • Quantity validation changed from < 0 to <= 0: "Quantity must be a positive integer"

Frontend Changes (Dashboard.jsx)

Added Features

1. Form Errors State

   • Added formErrors state to track validation errors per field

2. Client-Side Validation

   • Validates price > 0 (positive number)
   • Validates quantity > 0 (positive integer)
   • Validates name is not empty
   • Shows error messages below each field
   • Highlights input with red border on error

3. Real-Time Error Clearing

   • Errors clear when user modifies the field

4. Submit Button Behavior

   • Button disabled if there are validation errors
   • Prevents invalid submission to backend

5. Form Input Enhancements

   • Price field: type="number", step="0.01", min="0"
   • Quantity field: type="number", step="1", min="0"

Test Scenarios

Backend Testing

POST /api/products

• ✅ Price = -5 → 400, "Price must be a positive number"
• ✅ Price = 0 → 400, "Price must be a positive number"
• ✅ Price = 0.01 → 200, Success
• ✅ Price = "abc" → 400, "Price must be a positive number"
• ✅ Quantity = 0 → 400, "Quantity must be a positive integer"
• ✅ Quantity = -10 → 400, "Quantity must be a positive integer"
• ✅ Quantity = 1 → 200, Success
• ✅ Quantity = "xyz" → 400, "Quantity must be a positive integer"

PATCH /api/products/:id

• ✅ Price = -5 → 400, "Price must be a positive number"
• ✅ Price = 0 → 400, "Price must be a positive number"
• ✅ Price = 0.01 → 200, Success
• ✅ Quantity = 0 → 400, "Quantity must be a positive integer" (was allowed before)
• ✅ Quantity = -10 → 400, "Quantity must be a positive integer"
• ✅ Quantity = 1 → 200, Success

Frontend Testing

Dashboard Form Validation

• ✅ User enters price < 0 → Error shows: "Price must be a positive number"
• ✅ User enters price = 0 → Error shows: "Price must be a positive number"
• ✅ User enters price = 0.01 → No error, submit enabled
• ✅ User enters quantity = 0 → Error shows: "Quantity must be a positive integer"
• ✅ User enters quantity < 0 → Error shows: "Quantity must be a positive integer"
• ✅ User enters quantity = 1 → No error, submit enabled
• ✅ User clears price field → Error shows: "Price must be a positive number"
• ✅ User modifies field → Error clears in real-time
• ✅ Submit button disabled when errors exist
• ✅ Submit button enabled when all validations pass

Acceptance Criteria Verification

✅ POST /api/products with price ≤ 0 returns 400
✅ POST /api/products with quantity ≤ 0 returns 400
✅ POST /api/products with non-numeric price returns 400
✅ Dashboard form shows validation errors before submitting
✅ Valid products are still created successfully
✅ Same validation applies to product edit endpoint (PATCH)

Implementation Details

Backend Validation Logic

// POST and PATCH both now use:
if (isNaN(price) || price <= 0) 
  return err(res, 400, 'Price must be a positive number', 'validation_error');

if (isNaN(quantity) || quantity <= 0) 
  return err(res, 400, 'Quantity must be a positive integer', 'validation_error');

Frontend Validation Logic

const errors = {};
const price = parseFloat(form.price);
const quantity = parseInt(form.quantity, 10);

if (!form.price || isNaN(price) || price <= 0) {
  errors.price = 'Price must be a positive number';
}
if (!form.quantity || isNaN(quantity) || quantity <= 0) {
  errors.quantity = 'Quantity must be a positive integer';
}

if (Object.keys(errors).length > 0) {
  setFormErrors(errors);
  return; // Prevent submission
}

Files Modified

• backend/src/routes/products.js - Backend validation fixes
• frontend/src/pages/Dashboard.jsx - Frontend validation implementation