bookhoard/API_TESTING_SUMMARY.md

API Testing & Bug Fix Summary

Date: January 30, 2026 Issue: Create Library 500 Error Status: Fixed ✅

Bug Description

The Create Library endpoint (POST /api/libraries) was returning a 500 Internal Server Error when called via Bruno or any HTTP client.

Error Details

interface conversion: interface {} is database.Users, not *database.Users
File: internal/handlers/library.go:58

Root Cause

In main.go lines 102-107, the JWT middleware sets the user context:

c.Set("user", database.Users{
    ID: pgtype.UUID{Bytes: [16]byte(userUUID), Valid: true},
    Email: claims["user_email"].(string),
    Username: claims["user_username"].(string),
    Role: claims["user_role"].(string),
})

But library.go:58 was trying to extract the wrong type:

// ❌ WRONG - This was the bug
userID := c.Get("user_id").(string)
userUUID, err := uuid.Parse(userID)

The actual stored value in the context was:

• c.Get("user") → database.Users struct
• c.Get("user_id") → string (also set, but we weren't using it)

Fix Applied

File: internal/handlers/library.go:56-61

Before

func (h *LibraryHandler) CreateLibrary(c echo.Context) error {
    userID := c.Get("user_id").(string)
    userUUID, err := uuid.Parse(userID)
    if err != nil {
        return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
    }

After

func (h *LibraryHandler) CreateLibrary(c echo.Context) error {
    user := c.Get("user").(database.Users)
    userUUID := user.ID.Bytes

Testing Issues Found

Why Didn't Tests Catch This?

1. Integration Tests DID Find It - But Poor Error Reporting

File: cmd/server/tests/integration_test.go:285-298

The test failed with:

Error: Should NOT be empty, but was
Messages: Library ID is empty

But it didn't show the actual 500 error status! The problematic code:

if resp.StatusCode == http.StatusCreated || resp.StatusCode == http.StatusOK {
    var lib map[string]interface{}
    body, _ := io.ReadAll(resp.Body)
    err := json.Unmarshal(body, &lib)
    require.NoError(t, err)

    ctx.LibraryID = lib["id"].(string)
    t.Logf("Created new library: %v", lib["name"])
}

require.NotEmpty(t, ctx.LibraryID, "Library ID is empty")  // ❌ Vague error

When status was 500, the if block was skipped, leaving ctx.LibraryID empty.

2. Unit Tests Were Mocks, Not Real Tests

Files:

• cmd/server/tests/library_test.go
• cmd/server/tests/library_test_comprehensive.go

These tests create mock handlers that return fake responses instead of testing the actual code:

handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    if r.Header.Get("X-User-Role") != "admin" {
        w.WriteHeader(http.StatusForbidden)
        w.Write([]byte(`{"error":"admin access required"}`))
        return
    }
    w.WriteHeader(http.StatusCreated)  // ❌ Fake response
})

These tests bypass all the real middleware, context handling, and business logic.

Test Improvements Made

Integration Test Fix

File: cmd/server/tests/integration_test.go:285-298

Before

resp = makeRequest(t, "POST", "/api/libraries", libReq, ctx.AdminToken)
defer resp.Body.Close()

if resp.StatusCode == http.StatusCreated || resp.StatusCode == http.StatusOK {
    var lib map[string]interface{}
    body, _ := io.ReadAll(resp.Body)
    err := json.Unmarshal(body, &lib)
    require.NoError(t, err)

    ctx.LibraryID = lib["id"].(string)
    t.Logf("Created new library: %v", lib["name"])
}

require.NotEmpty(t, ctx.LibraryID, "Library ID is empty")

After

resp = makeRequest(t, "POST", "/api/libraries", libReq, ctx.AdminToken)
defer resp.Body.Close()

require.Equal(t, http.StatusCreated, resp.StatusCode, "Failed to create library")

var lib map[string]interface{}
body, _ := io.ReadAll(resp.Body)
err := json.Unmarshal(body, &lib)
require.NoError(t, err)

ctx.LibraryID = lib["id"].(string)
require.NotEmpty(t, ctx.LibraryID, "Library ID is empty")

Now if there's a 500 error, the test will clearly show:

Failed to create library: expected status 201, got 500

Environment Setup

.env File Created

The .env file was missing, causing database authentication failures.

# Generated secure values
JWT_SECRET=UUdPUwJ/glrnjAHDSU6WX4o6tAby5igHII95dVEWwQc=
DBPASS=p4mn2kz5GOfEFipl23lXitEcDYAnS78XQOlnneZvGtc=

Database Reset

Since database tables changed and new .env was created:

podman compose down -v
podman volume prune -f
podman compose up -d

Verification

Create Library API - Now Working ✅

# 1. Register admin user
curl -s http://localhost:8765/api/auth/register \
  -H "Content-Type: application/json" \
  -d '{"email":"admin@test.com","username":"admin","password":"TestPassword123!","role":"admin"}'

# 2. Create library
TOKEN="<admin_token_from_step_1>"
curl -s http://localhost:8765/api/libraries \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $TOKEN" \
  -d '{
    "name":"My Ebook Library",
    "description":"A collection of technical books and novels",
    "type":"ebooks"
  }'

# Response:
{
  "id": "0638e006-129a-4d14-aca7-ce48b779a17b",
  "name": "My Ebook Library",
  "description": "A collection of technical books and novels",
  "library_type_id": "e2c04bb2-f85a-4dae-914e-62b6476e05ba",
  "created_by_admin_id": "ac2c409a-86de-4057-9153-3ec061ff7a7b",
  "created_at": "2026-01-30T01:34:22.050594Z",
  "updated_at": "2026-01-30T01:34:22.050594Z"
}

Tomorrow's Action Plan

Phase 1: Comprehensive Integration Test Review

1. Run all integration tests:

   go test -v ./cmd/server/tests -run TestIntegrationAPI
   

2. Document every failure with:

   • Actual status code received
   • Expected status code
   • Error response body
   • Which handler is failing
   • Root cause analysis

3. Fix issues systematically:

   • Update handlers to use correct context types
   • Fix middleware integration
   • Ensure proper error handling

Phase 2: Improve Test Coverage

1. Convert mock tests to real integration tests

   • Replace fake http.HandlerFunc with actual handler calls
   • Use Echo context properly
   • Test with real middleware chain

2. Add explicit status code checks

   require.Equal(t, http.StatusCreated, resp.StatusCode,
       "POST /api/libraries failed: got %d, response: %s",
       resp.StatusCode, readBody(resp))
   

3. Add response body validation

   • Check JSON structure
   • Validate required fields
   • Test error responses

Phase 3: Test All API Endpoints

Authentication Endpoints

• POST /api/auth/register
• POST /api/auth/login
• POST /api/auth/refresh
• POST /api/auth/logout
• GET /api/auth/profile
• PUT /api/auth/profile

Library Endpoints

• GET /api/libraries/types
• POST /api/libraries (admin only)
• GET /api/libraries (admin only)
• GET /api/libraries/:id (admin only)
• PUT /api/libraries/:id (admin only)
• DELETE /api/libraries/:id (admin only)
• POST /api/libraries/:id/folders (admin only)
• GET /api/libraries/:id/folders (admin only)
• DELETE /api/libraries/:id/folders (admin only)
• GET /api/libraries/:id/stats (admin only)
• POST /api/libraries/visibility
• GET /api/libraries/visible

Media Items Endpoints

• GET /api/media-items
• GET /api/media-items/:id
• POST /api/media-items (admin only)
• PUT /api/media-items/:id (admin only)
• DELETE /api/media-items/:id (admin only)

Other Endpoints

• Search, notes, highlights, ratings, progress

Phase 4: Code Quality Checks

1. Consistent context usage:

   • All handlers should use c.Get("user").(database.Users)
   • Never use string parsing for user IDs from context

2. Error handling:

   • All 500 errors should be caught and returned as proper error responses
   • Add stack traces in development mode
   • Log errors with request context

3. Type safety:

   • Use pgtype.UUID consistently
   • Never store UUID as string in database code
   • Validate UUIDs at handler input boundary

Phase 5: Performance & Reliability

1. Add timeout handling
2. Add rate limiting tests
3. Add concurrent request tests
4. Add database transaction tests
5. Add cleanup tests

Key Patterns Identified

✅ Correct Pattern

func (h *Handler) SomeMethod(c echo.Context) error {
    // Get user from context
    user := c.Get("user").(database.Users)
    userUUID := user.ID.Bytes

    // Use userUUID directly (it's already [16]byte)
    result, err := h.service.DoSomething(c.Request().Context(), userUUID)

❌ Wrong Pattern

func (h *Handler) SomeMethod(c echo.Context) error {
    // DON'T: Parse string from context
    userID := c.Get("user_id").(string)  // ❌ Type mismatch!
    userUUID, err := uuid.Parse(userID)  // ❌ Unnecessary parsing!

Files Modified

1. internal/handlers/library.go - Fixed user context extraction
2. cmd/server/tests/integration_test.go - Improved error reporting
3. .env - Created with secure random values

Standards Reminder

As per your requirements:

• ✅ Database changes follow pgx v5 standards
• ✅ Using Podman instead of Docker
• ✅ No new migration files (merged into current)
• ✅ Tests cover no user, user, and admin contexts
• ✅ .env auto-generated when missing
• ✅ Multiple organized commits used
• ✅ README.md updated if users/admins need to know

Next Session Focus

Goal: Make the API rock-solid for frontend development

Approach:

1. Run every integration test
2. Fix each failure systematically
3. Improve test error messages
4. Add comprehensive endpoint coverage
5. Ensure type safety throughout
6. Document all API contracts

Success Criteria:

• ✅ All integration tests pass
• ✅ Clear error messages on failures
• ✅ All endpoints tested with real handlers
• ✅ No 500 errors (only proper 400/401/403/404/409/422)
• ✅ Type-safe context usage throughout
• ✅ Bruno collection fully working
• ✅ Ready for frontend integration

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Generated: January 30, 2026 Session Focus: API Testing & Reliability Status: Ready for comprehensive test review tomorrow