Add testing guide and enhance BmsFreeSendTest for image handling

- Introduced a comprehensive testing guide in TESTING.md, detailing test commands, structure, and E2E test configuration.
- Updated BmsFreeSendTest to correct image handling by specifying accurate image types for wide item lists.

Author: Palbahngmiyine

docs/TESTING.md

@@ -0,0 +1,105 @@
+# Testing Guide
+
+## Quick Start
+
+```bash
+# Run all tests
+composer test
+
+# Run only unit tests
+composer test:unit
+
+# Run only E2E tests
+composer test:e2e
+
+# Run tests with coverage report
+composer test:coverage
+```
+
+## Test Structure
+
+```
+tests/
+├── Models/           # Unit tests (validation, model behavior)
+│   └── Kakao/
+│       └── Bms/
+│           ├── BmsModelsTest.php
+│           └── BmsValidatorTest.php
+└── E2E/              # End-to-end tests (actual API calls)
+    └── BmsFreeSendTest.php
+```
+
+## E2E Tests Configuration
+
+E2E tests require environment variables to connect to the SOLAPI API:
+
+```bash
+export SOLAPI_API_KEY="your-api-key"
+export SOLAPI_API_SECRET="your-api-secret"
+export SOLAPI_KAKAO_PF_ID="your-kakao-pf-id"
+export SOLAPI_SENDER_NUMBER="01012345678"
+export SOLAPI_RECIPIENT_NUMBER="01087654321"
+export SOLAPI_TEST_IMAGE_PATH="/path/to/test/image.jpg"  # Optional
+```
+
+Without these variables, E2E tests will be skipped automatically.
+
+### Running E2E Tests
+
+```bash
+# Set environment variables and run
+SOLAPI_API_KEY=xxx SOLAPI_API_SECRET=xxx \
+SOLAPI_KAKAO_PF_ID=xxx \
+SOLAPI_SENDER_NUMBER=01012345678 \
+SOLAPI_RECIPIENT_NUMBER=01087654321 \
+composer test:e2e
+```
+
+Or use a `.env` file with a tool like `dotenv`:
+
+```bash
+# .env.test (do not commit this file)
+SOLAPI_API_KEY=your-api-key
+SOLAPI_API_SECRET=your-api-secret
+SOLAPI_KAKAO_PF_ID=your-pf-id
+SOLAPI_SENDER_NUMBER=01012345678
+SOLAPI_RECIPIENT_NUMBER=01087654321
+```
+
+## PHPUnit Direct Commands
+
+```bash
+# Run specific test file
+./vendor/bin/phpunit tests/E2E/BmsFreeSendTest.php
+
+# Run specific test method
+./vendor/bin/phpunit --filter testSendBmsTextMinimal
+
+# Run with verbose output
+./vendor/bin/phpunit --testdox
+
+# List all available tests
+./vendor/bin/phpunit --list-tests
+```
+
+## Test Suites
+
+| Suite | Command | Description |
+|-------|---------|-------------|
+| All | `composer test` | Run all tests |
+| Unit | `composer test:unit` | Unit tests only (no API calls) |
+| E2E | `composer test:e2e` | E2E tests (requires env vars) |
+
+## E2E Test Cases
+
+| Test | BMS Type | Description |
+|------|----------|-------------|
+| `testSendBmsTextMinimal` | TEXT | Minimal text message |
+| `testSendBmsTextWithButtons` | TEXT | Text with buttons and coupon |
+| `testSendBmsImage` | IMAGE | Image message |
+| `testSendBmsWide` | WIDE | Wide format message |
+| `testSendBmsCommerce` | COMMERCE | Commerce/product message |
+| `testSendBmsWideItemList` | WIDE_ITEM_LIST | Wide item list (main + 3 sub items) |
+| `testSendBmsCarouselFeed` | CAROUSEL_FEED | Carousel feed message |
+| `testSendBmsCarouselCommerce` | CAROUSEL_COMMERCE | Carousel commerce message |
+| `testSendBmsPremiumVideo` | PREMIUM_VIDEO | Premium video message |

tests/E2E/BmsFreeSendTest.php

@@ -341,9 +341,9 @@ public function testSendBmsWideItemList(): void
 
         try {
             // Upload main image (2:1 ratio)
-            $mainImageId = $this->messageService->uploadFile($mainImagePath, 'BMS_WIDE_ITEM_LIST_MAIN');
+            $mainImageId = $this->messageService->uploadFile($mainImagePath, 'BMS_WIDE_MAIN_ITEM_LIST');
             // Upload sub images (1:1 ratio)
-            $subImageId = $this->messageService->uploadFile($subImagePath, 'BMS_WIDE_ITEM_LIST_SUB');
+            $subImageId = $this->messageService->uploadFile($subImagePath, 'BMS_WIDE_SUB_ITEM_LIST');
 
             $mainItem = new BmsMainWideItem();
             $mainItem->setImageId($mainImageId)