style: replace type interface{} with any

server/pkg/service/middleware.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"time"
 
+	"git.umbrella.haus/ae/notatest/pkg/data"
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
 	"github.com/golang-jwt/jwt/v5"
@@ -18,8 +19,6 @@ const (
 	defaultLogMsg    = "incoming request"
 )
 
-type userCtxKey struct{}
-
 // Get JWT bearer from request's authorization header, parse it with custom user claims, and
 // ensure its validity before attaching the claims to the request's context.
 func authMiddleware(jwtSecret string, expectedType string) func(http.Handler) http.Handler {
@@ -30,7 +29,7 @@ func authMiddleware(jwtSecret string, expectedType string) func(http.Handler) ht
 				respondError(w, http.StatusUnauthorized, fmt.Sprintf("Unauthorized: %s", err))
 			}
 
-			token, err := jwt.ParseWithClaims(tokenString, &userClaims{}, func(token *jwt.Token) (interface{}, error) {
+			token, err := jwt.ParseWithClaims(tokenString, &userClaims{}, func(token *jwt.Token) (any, error) {
 				return []byte(jwtSecret), nil
 			})
 			if err != nil || !token.Valid {
@@ -109,6 +108,46 @@ func userCtx(store UserStore) func(http.Handler) http.Handler {
 	}
 }
 
+// Append note data into request's context based on note ID as a URL parameter and user ID as
+// context parameter.
+func noteCtx(store NoteStore) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			noteIDStr := chi.URLParam(r, "id")
+			noteID, err := uuid.Parse(noteIDStr)
+			if err != nil {
+				respondError(w, http.StatusNotFound, "Invalid note ID")
+				return
+			}
+
+			// NOTE: user must already be in the context (e.g. via JWT middleware)
+			user, ok := r.Context().Value(userCtxKey{}).(*userClaims)
+			if !ok {
+				respondError(w, http.StatusUnauthorized, "Unauthorized")
+				return
+			}
+
+			userID, err := uuid.Parse(user.Subject)
+			if err != nil {
+				respondError(w, http.StatusInternalServerError, "Invalid user ID")
+				return
+			}
+
+			note, err := store.GetNote(r.Context(), data.GetNoteParams{
+				ID:     noteID,
+				UserID: userID,
+			})
+			if err != nil {
+				respondError(w, http.StatusNotFound, "Note not found")
+				return
+			}
+
+			ctx := context.WithValue(r.Context(), noteCtxKey{}, note)
+			next.ServeHTTP(w, r.WithContext(ctx))
+		})
+	}
+}
+
 // Zerolog compatible logger middleware. Automatically logs and recovers from errors with HTTP 500
 // response, by default logs to INFO level.
 func loggerMiddleware(log *zerolog.Logger) func(http.Handler) http.Handler {
@@ -136,7 +175,7 @@ func loggerMiddleware(log *zerolog.Logger) func(http.Handler) http.Handler {
 				log.Info().
 					Str("type", "access").
 					Timestamp().
-					Fields(map[string]interface{}{
+					Fields(map[string]any{
 						"remote_ip":  r.RemoteAddr,
 						"url":        r.URL.Path,
 						"proto":      r.Proto,

server/pkg/service/middleware_test.go

@@ -232,9 +232,21 @@ func TestUserCtxMiddleware(t *testing.T) {
 		urlID      string
 		statusCode int
 	}{
-		{"valid ID", validUserID.String(), http.StatusOK},
-		{"invalid ID", invalidUserID, http.StatusNotFound},
-		{"non existent ID", uuid.New().String(), http.StatusNotFound},
+		{
+			"valid ID",
+			validUserID.String(),
+			http.StatusOK,
+		},
+		{
+			"invalid ID",
+			invalidUserID,
+			http.StatusNotFound,
+		},
+		{
+			"non existent ID",
+			uuid.New().String(),
+			http.StatusNotFound,
+		},
 	}
 
 	for _, tc := range tests {
@@ -257,6 +269,97 @@ func TestUserCtxMiddleware(t *testing.T) {
 	}
 }
 
+func TestNoteCtxMiddleware(t *testing.T) {
+	userID := uuid.New()
+	noteID := uuid.New()
+
+	tests := []struct {
+		name       string
+		noteID     string
+		user       any
+		mock       func(*mockNoteStore)
+		statusCode int
+	}{
+		{
+			"invalid note ID",
+			"invalid",
+			&userClaims{RegisteredClaims: jwt.RegisteredClaims{
+				Subject: userID.String(),
+			}},
+			func(m *mockNoteStore) {},
+			http.StatusNotFound,
+		},
+		{
+			"unauthorized user",
+			noteID.String(),
+			nil,
+			func(m *mockNoteStore) {},
+			http.StatusUnauthorized,
+		},
+		{
+			"note not found",
+			noteID.String(),
+			&userClaims{RegisteredClaims: jwt.RegisteredClaims{
+				Subject: userID.String(),
+			}},
+			func(m *mockNoteStore) {
+				m.GetNoteFunc = func(ctx context.Context, arg data.GetNoteParams) (data.Note, error) {
+					return data.Note{}, errors.New("not found")
+				}
+			},
+			http.StatusNotFound,
+		},
+		{
+			"success",
+			noteID.String(),
+			&userClaims{RegisteredClaims: jwt.RegisteredClaims{
+				Subject: userID.String(),
+			}},
+			func(m *mockNoteStore) {
+				m.GetNoteFunc = func(ctx context.Context, arg data.GetNoteParams) (data.Note, error) {
+					assert.Equal(t, noteID, arg.ID)
+					assert.Equal(t, userID, arg.UserID)
+					return data.Note{ID: noteID}, nil
+				}
+			},
+			http.StatusOK,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			mockStore := &mockNoteStore{}
+			tc.mock(mockStore)
+
+			handler := noteCtx(mockStore)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				_, ok := r.Context().Value(noteCtxKey{}).(data.Note)
+				assert.True(t, ok)
+				w.WriteHeader(http.StatusOK)
+			}))
+
+			req := httptest.NewRequest("GET", fmt.Sprintf("/notes/%s", tc.noteID), nil)
+
+			// Chi router context mocks ID passed in a URL parameter
+			rctx := chi.NewRouteContext()
+			rctx.URLParams.Add("id", tc.noteID)
+			req = req.WithContext(context.WithValue(req.Context(), chi.RouteCtxKey, rctx))
+
+			if tc.user != nil {
+				req = req.WithContext(context.WithValue(
+					req.Context(),
+					userCtxKey{},
+					tc.user,
+				))
+			}
+
+			w := httptest.NewRecorder()
+			handler.ServeHTTP(w, req)
+
+			assert.Equal(t, tc.statusCode, w.Code)
+		})
+	}
+}
+
 func generateTestToken(t *testing.T, secret, tokenType, userID string, isAdmin bool, opts ...func(*userClaims)) string {
 	t.Helper()
 

server/pkg/service/notes.go

@@ -1,19 +1,262 @@
 package service
 
 import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"strconv"
+
+	"git.umbrella.haus/ae/notatest/pkg/data"
 	"github.com/go-chi/chi/v5"
+	"github.com/google/uuid"
 )
 
+type noteCtxKey struct{}
+
 // Mockable database operations interface
 type NoteStore interface {
-	// TODO: implement
+	CreateNote(ctx context.Context, userID uuid.UUID) (data.Note, error)
+	DeleteNote(ctx context.Context, arg data.DeleteNoteParams) error
+	GetNote(ctx context.Context, arg data.GetNoteParams) (data.Note, error)
+	ListNotes(ctx context.Context, arg data.ListNotesParams) ([]data.Note, error)
+	CreateNoteVersion(ctx context.Context, arg data.CreateNoteVersionParams) (data.NoteVersion, error)
+	FindDuplicateContent(ctx context.Context, arg data.FindDuplicateContentParams) (bool, error)
+	GetNoteVersion(ctx context.Context, arg data.GetNoteVersionParams) (data.NoteVersion, error)
+	GetNoteVersions(ctx context.Context, arg data.GetNoteVersionsParams) ([]data.NoteVersion, error)
 }
 
 type notesResource struct {
-	Notes NoteStore
+	JWTSecret string
+	Notes     NoteStore
 }
 
 func (rs notesResource) Routes() chi.Router {
 	r := chi.NewRouter()
+
+	r.Group(func(r chi.Router) {
+		r.Use(requireAccessToken(rs.JWTSecret))
+
+		r.Post("/", rs.CreateNote) // POST /notes - note creation
+		r.Get("/", rs.ListNotes)   // GET /notes - get all notes
+
+		r.Route("/{id}", func(r chi.Router) {
+			r.Use(noteCtx(rs.Notes))
+
+			r.Get("/", rs.GetNote)       // GET /notes/{id} - get specific note
+			r.Delete("/", rs.DeleteNote) // DELETE /notes/{id} - delete specific note
+
+			r.Route("/versions", func(r chi.Router) {
+				r.Post("/", rs.CreateNoteVersion)      // POST /notes/{id}/versions - create new version
+				r.Get("/", rs.ListNoteVersions)        // GET /notes/{id}/versions - get all existing versions
+				r.Get("/{version}", rs.GetNoteVersion) // GET /notes/{id}/versions/{version} - get specific version
+			})
+		})
+	})
+
 	return r
 }
+
+func (rs *notesResource) CreateNote(w http.ResponseWriter, r *http.Request) {
+	user, ok := r.Context().Value(userCtxKey{}).(*userClaims)
+	if !ok {
+		respondError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	userID, err := uuid.Parse(user.Subject)
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Invalid user ID")
+		return
+	}
+
+	note, err := rs.Notes.CreateNote(r.Context(), userID)
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to create note")
+		return
+	}
+
+	respondJSON(w, http.StatusCreated, note)
+}
+
+func (rs *notesResource) ListNotes(w http.ResponseWriter, r *http.Request) {
+	user, ok := r.Context().Value(userCtxKey{}).(*userClaims)
+	if !ok {
+		respondError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	userID, err := uuid.Parse(user.Subject)
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Invalid user ID")
+		return
+	}
+
+	limit, offset := getPaginationParams(r)
+
+	notes, err := rs.Notes.ListNotes(r.Context(), data.ListNotesParams{
+		UserID: userID,
+		Limit:  limit,
+		Offset: offset,
+	})
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to retrieve notes")
+		return
+	}
+
+	respondJSON(w, http.StatusOK, notes)
+}
+
+func (rs *notesResource) GetNote(w http.ResponseWriter, r *http.Request) {
+	note, ok := r.Context().Value(noteCtxKey{}).(data.Note)
+	if !ok {
+		respondError(w, http.StatusNotFound, "Note not found")
+		return
+	}
+
+	respondJSON(w, http.StatusOK, note)
+}
+
+func (rs *notesResource) DeleteNote(w http.ResponseWriter, r *http.Request) {
+	note, ok := r.Context().Value(noteCtxKey{}).(data.Note)
+	if !ok {
+		respondError(w, http.StatusNotFound, "Note not found")
+		return
+	}
+
+	user, ok := r.Context().Value(userCtxKey{}).(*userClaims)
+	if !ok {
+		respondError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	userID, err := uuid.Parse(user.Subject)
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Invalid user ID")
+		return
+	}
+
+	err = rs.Notes.DeleteNote(r.Context(), data.DeleteNoteParams{
+		ID:     note.ID,
+		UserID: userID,
+	})
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to delete note")
+		return
+	}
+
+	w.WriteHeader(http.StatusNoContent)
+}
+
+func (rs *notesResource) CreateNoteVersion(w http.ResponseWriter, r *http.Request) {
+	note, ok := r.Context().Value(noteCtxKey{}).(data.Note)
+	if !ok {
+		respondError(w, http.StatusNotFound, "Note not found")
+		return
+	}
+
+	var req struct {
+		Title   string `json:"title"`
+		Content string `json:"content"`
+	}
+
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		respondError(w, http.StatusBadRequest, "Invalid request body")
+		return
+	}
+
+	// De-duplication check
+	duplicate, err := rs.Notes.FindDuplicateContent(r.Context(), data.FindDuplicateContentParams{
+		NoteID:  note.ID,
+		Column2: []byte(req.Title),
+		Column3: []byte(req.Content),
+	})
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to check for duplicate content")
+		return
+	}
+	if duplicate {
+		respondError(w, http.StatusConflict, "Duplicate content detected")
+		return
+	}
+
+	version, err := rs.Notes.CreateNoteVersion(r.Context(), data.CreateNoteVersionParams{
+		NoteID:  note.ID,
+		Title:   req.Title,
+		Content: req.Content,
+	})
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to create note version")
+		return
+	}
+
+	respondJSON(w, http.StatusCreated, version)
+}
+
+func (rs *notesResource) ListNoteVersions(w http.ResponseWriter, r *http.Request) {
+	note, ok := r.Context().Value(noteCtxKey{}).(data.Note)
+	if !ok {
+		respondError(w, http.StatusNotFound, "Note not found")
+		return
+	}
+
+	limit, offset := getPaginationParams(r)
+
+	versions, err := rs.Notes.GetNoteVersions(r.Context(), data.GetNoteVersionsParams{
+		NoteID: note.ID,
+		Limit:  limit,
+		Offset: offset,
+	})
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to retrieve versions")
+		return
+	}
+
+	respondJSON(w, http.StatusOK, versions)
+}
+
+func (rs *notesResource) GetNoteVersion(w http.ResponseWriter, r *http.Request) {
+	note, ok := r.Context().Value(noteCtxKey{}).(data.Note)
+	if !ok {
+		respondError(w, http.StatusNotFound, "Note not found")
+		return
+	}
+
+	versionStr := chi.URLParam(r, "version")
+	versionNumber, err := strconv.ParseInt(versionStr, 10, 32)
+	if err != nil {
+		respondError(w, http.StatusBadRequest, "Invalid version number")
+		return
+	}
+
+	version, err := rs.Notes.GetNoteVersion(r.Context(), data.GetNoteVersionParams{
+		NoteID:        note.ID,
+		VersionNumber: int32(versionNumber),
+	})
+	if err != nil {
+		respondError(w, http.StatusNotFound, "Version not found")
+		return
+	}
+
+	respondJSON(w, http.StatusOK, version)
+}
+
+func getPaginationParams(r *http.Request) (limit int32, offset int32) {
+	defaultLimit := 50
+	defaultOffset := 0
+
+	limitStr := r.URL.Query().Get("limit")
+	if limitStr != "" {
+		if l, err := strconv.Atoi(limitStr); err == nil && l > 0 {
+			defaultLimit = l
+		}
+	}
+
+	offsetStr := r.URL.Query().Get("offset")
+	if offsetStr != "" {
+		if o, err := strconv.Atoi(offsetStr); err == nil && o >= 0 {
+			defaultOffset = o
+		}
+	}
+
+	return int32(defaultLimit), int32(defaultOffset)
+}

server/pkg/service/notes_test.go

@@ -0,0 +1,364 @@
+package service
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"git.umbrella.haus/ae/notatest/pkg/data"
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+)
+
+type mockNoteStore struct {
+	CreateNoteFunc           func(context.Context, uuid.UUID) (data.Note, error)
+	DeleteNoteFunc           func(context.Context, data.DeleteNoteParams) error
+	GetNoteFunc              func(context.Context, data.GetNoteParams) (data.Note, error)
+	ListNotesFunc            func(context.Context, data.ListNotesParams) ([]data.Note, error)
+	CreateNoteVersionFunc    func(context.Context, data.CreateNoteVersionParams) (data.NoteVersion, error)
+	FindDuplicateContentFunc func(context.Context, data.FindDuplicateContentParams) (bool, error)
+	GetNoteVersionFunc       func(context.Context, data.GetNoteVersionParams) (data.NoteVersion, error)
+	GetNoteVersionsFunc      func(context.Context, data.GetNoteVersionsParams) ([]data.NoteVersion, error)
+}
+
+func (m *mockNoteStore) CreateNote(ctx context.Context, userID uuid.UUID) (data.Note, error) {
+	return m.CreateNoteFunc(ctx, userID)
+}
+
+func (m *mockNoteStore) DeleteNote(ctx context.Context, arg data.DeleteNoteParams) error {
+	return m.DeleteNoteFunc(ctx, arg)
+}
+
+func (m *mockNoteStore) GetNote(ctx context.Context, arg data.GetNoteParams) (data.Note, error) {
+	return m.GetNoteFunc(ctx, arg)
+}
+
+func (m *mockNoteStore) ListNotes(ctx context.Context, arg data.ListNotesParams) ([]data.Note, error) {
+	return m.ListNotesFunc(ctx, arg)
+}
+
+func (m *mockNoteStore) CreateNoteVersion(ctx context.Context, arg data.CreateNoteVersionParams) (data.NoteVersion, error) {
+	return m.CreateNoteVersionFunc(ctx, arg)
+}
+
+func (m *mockNoteStore) FindDuplicateContent(ctx context.Context, arg data.FindDuplicateContentParams) (bool, error) {
+	return m.FindDuplicateContentFunc(ctx, arg)
+}
+
+func (m *mockNoteStore) GetNoteVersion(ctx context.Context, arg data.GetNoteVersionParams) (data.NoteVersion, error) {
+	return m.GetNoteVersionFunc(ctx, arg)
+}
+
+func (m *mockNoteStore) GetNoteVersions(ctx context.Context, arg data.GetNoteVersionsParams) ([]data.NoteVersion, error) {
+	return m.GetNoteVersionsFunc(ctx, arg)
+}
+
+func TestNotes_CreateNote(t *testing.T) {
+	userID := uuid.New()
+	testNote := data.Note{ID: uuid.New(), UserID: userID}
+
+	tests := []struct {
+		name       string
+		mock       func(*mockNoteStore)
+		statusCode int
+	}{
+		{
+			"success",
+			func(m *mockNoteStore) {
+				m.CreateNoteFunc = func(_ context.Context, uid uuid.UUID) (data.Note, error) {
+					assert.Equal(t, userID, uid)
+					return testNote, nil
+				}
+			},
+			http.StatusCreated,
+		},
+		{
+			"database error",
+			func(m *mockNoteStore) {
+				m.CreateNoteFunc = func(context.Context, uuid.UUID) (data.Note, error) {
+					return data.Note{}, errors.New("db error")
+				}
+			},
+			http.StatusInternalServerError,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			mockStore := &mockNoteStore{}
+			tc.mock(mockStore)
+
+			rs := notesResource{Notes: mockStore}
+			req := httptest.NewRequest("POST", "/", nil)
+			req = req.WithContext(context.WithValue(
+				req.Context(),
+				userCtxKey{},
+				&userClaims{RegisteredClaims: jwt.RegisteredClaims{
+					Subject: userID.String(),
+				}},
+			))
+
+			w := httptest.NewRecorder()
+			rs.CreateNote(w, req)
+
+			assert.Equal(t, tc.statusCode, w.Code)
+			if tc.statusCode == http.StatusCreated {
+				var note data.Note
+				json.Unmarshal(w.Body.Bytes(), &note)
+				assert.Equal(t, testNote.ID, note.ID)
+			}
+		})
+	}
+}
+
+func TestNotes_ListNotes(t *testing.T) {
+	userID := uuid.New()
+	notes := []data.Note{
+		{ID: uuid.New(), UserID: userID},
+		{ID: uuid.New(), UserID: userID},
+	}
+
+	tests := []struct {
+		name       string
+		query      string
+		mock       func(*mockNoteStore)
+		statusCode int
+	}{
+		{
+			"success",
+			"",
+			func(m *mockNoteStore) {
+				m.ListNotesFunc = func(_ context.Context, arg data.ListNotesParams) ([]data.Note, error) {
+					assert.Equal(t, userID, arg.UserID)
+					return notes, nil
+				}
+			},
+			http.StatusOK,
+		},
+		{
+			"with pagination",
+			"?limit=10&offset=20",
+			func(m *mockNoteStore) {
+				m.ListNotesFunc = func(_ context.Context, arg data.ListNotesParams) ([]data.Note, error) {
+					assert.EqualValues(t, 10, arg.Limit)
+					assert.EqualValues(t, 20, arg.Offset)
+					return notes, nil
+				}
+			},
+			http.StatusOK,
+		},
+		{
+			"database error",
+			"",
+			func(m *mockNoteStore) {
+				m.ListNotesFunc = func(context.Context, data.ListNotesParams) ([]data.Note, error) {
+					return nil, errors.New("db error")
+				}
+			},
+			http.StatusInternalServerError,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			mockStore := &mockNoteStore{}
+			tc.mock(mockStore)
+
+			rs := notesResource{Notes: mockStore}
+			req := httptest.NewRequest("GET", fmt.Sprintf("/%s", tc.query), nil)
+			req = req.WithContext(context.WithValue(
+				req.Context(),
+				userCtxKey{},
+				&userClaims{RegisteredClaims: jwt.RegisteredClaims{
+					Subject: userID.String(),
+				}},
+			))
+
+			w := httptest.NewRecorder()
+			rs.ListNotes(w, req)
+
+			assert.Equal(t, tc.statusCode, w.Code)
+		})
+	}
+}
+
+func TestNotes_GetNote(t *testing.T) {
+	noteID := uuid.New()
+	userID := uuid.New()
+	validNote := data.Note{ID: noteID, UserID: userID}
+
+	t.Run("success", func(t *testing.T) {
+		rs := notesResource{}
+		req := httptest.NewRequest("GET", "/", nil)
+		req = req.WithContext(context.WithValue(
+			req.Context(),
+			noteCtxKey{},
+			validNote,
+		))
+
+		w := httptest.NewRecorder()
+		rs.GetNote(w, req)
+
+		assert.Equal(t, http.StatusOK, w.Code)
+		var note data.Note
+		json.Unmarshal(w.Body.Bytes(), &note)
+		assert.Equal(t, validNote.ID, note.ID)
+	})
+
+	t.Run("not found", func(t *testing.T) {
+		rs := notesResource{}
+		req := httptest.NewRequest("GET", "/", nil)
+		w := httptest.NewRecorder()
+		rs.GetNote(w, req)
+
+		assert.Equal(t, http.StatusNotFound, w.Code)
+	})
+}
+
+func TestNotes_DeleteNote(t *testing.T) {
+	noteID := uuid.New()
+	userID := uuid.New()
+	validNote := data.Note{ID: noteID, UserID: userID}
+
+	t.Run("success", func(t *testing.T) {
+		mockStore := &mockNoteStore{
+			DeleteNoteFunc: func(_ context.Context, arg data.DeleteNoteParams) error {
+				assert.Equal(t, noteID, arg.ID)
+				assert.Equal(t, userID, arg.UserID)
+				return nil
+			},
+		}
+
+		rs := notesResource{Notes: mockStore}
+		req := httptest.NewRequest("DELETE", "/", nil)
+		req = req.WithContext(context.WithValue(
+			req.Context(),
+			noteCtxKey{},
+			validNote,
+		))
+		req = req.WithContext(context.WithValue(
+			req.Context(),
+			userCtxKey{},
+			&userClaims{RegisteredClaims: jwt.RegisteredClaims{
+				Subject: userID.String(),
+			}},
+		))
+
+		w := httptest.NewRecorder()
+		rs.DeleteNote(w, req)
+
+		assert.Equal(t, http.StatusNoContent, w.Code)
+	})
+
+	t.Run("database error", func(t *testing.T) {
+		mockStore := &mockNoteStore{
+			DeleteNoteFunc: func(context.Context, data.DeleteNoteParams) error {
+				return errors.New("db error")
+			},
+		}
+
+		rs := notesResource{Notes: mockStore}
+		req := httptest.NewRequest("DELETE", "/", nil)
+		req = req.WithContext(context.WithValue(
+			req.Context(),
+			noteCtxKey{},
+			validNote,
+		))
+		req = req.WithContext(context.WithValue(
+			req.Context(),
+			userCtxKey{},
+			&userClaims{RegisteredClaims: jwt.RegisteredClaims{
+				Subject: userID.String(),
+			}},
+		))
+
+		w := httptest.NewRecorder()
+		rs.DeleteNote(w, req)
+
+		assert.Equal(t, http.StatusInternalServerError, w.Code)
+	})
+}
+
+func TestNotes_CreateNoteVersion(t *testing.T) {
+	noteID := uuid.New()
+	validRequest := `{"title": "Test", "content": "Content"}`
+
+	tests := []struct {
+		name       string
+		body       string
+		mock       func(*mockNoteStore)
+		statusCode int
+	}{
+		{
+			"success",
+			validRequest,
+			func(m *mockNoteStore) {
+				m.FindDuplicateContentFunc = func(context.Context, data.FindDuplicateContentParams) (bool, error) {
+					return false, nil
+				}
+				m.CreateNoteVersionFunc = func(_ context.Context, arg data.CreateNoteVersionParams) (data.NoteVersion, error) {
+					assert.Equal(t, noteID, arg.NoteID)
+					return data.NoteVersion{}, nil
+				}
+			},
+			http.StatusCreated,
+		},
+		{
+			"duplicate content",
+			validRequest,
+			func(m *mockNoteStore) {
+				m.FindDuplicateContentFunc = func(context.Context, data.FindDuplicateContentParams) (bool, error) {
+					return true, nil
+				}
+			},
+			http.StatusConflict,
+		},
+		{
+			"invalid request",
+			"{invalid}",
+			func(m *mockNoteStore) {},
+			http.StatusBadRequest,
+		},
+		{
+			"database error",
+			validRequest,
+			func(m *mockNoteStore) {
+				m.FindDuplicateContentFunc = func(context.Context, data.FindDuplicateContentParams) (bool, error) {
+					return false, nil
+				}
+				m.CreateNoteVersionFunc = func(context.Context, data.CreateNoteVersionParams) (data.NoteVersion, error) {
+					return data.NoteVersion{}, errors.New("db error")
+				}
+			},
+			http.StatusInternalServerError,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			mockStore := &mockNoteStore{}
+			tc.mock(mockStore)
+
+			rs := notesResource{Notes: mockStore}
+			req := httptest.NewRequest("POST", "/", strings.NewReader(tc.body))
+			req = req.WithContext(context.WithValue(
+				req.Context(),
+				noteCtxKey{},
+				data.Note{ID: noteID},
+			))
+
+			w := httptest.NewRecorder()
+			rs.CreateNoteVersion(w, req)
+
+			assert.Equal(t, tc.statusCode, w.Code)
+		})
+	}
+}
+
+// TODO: add similar tests for `ListNoteVersions` and `GetNoteVersion`

server/pkg/service/users.go

@@ -14,6 +14,8 @@ import (
 	"golang.org/x/crypto/bcrypt"
 )
 
+type userCtxKey struct{}
+
 // Mockable database operations interface
 type UserStore interface {
 	CreateUser(ctx context.Context, arg data.CreateUserParams) (data.User, error)
@@ -124,9 +126,9 @@ func (rs usersResource) List(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Output sanitization
-	var output []map[string]interface{}
+	var output []map[string]any
 	for _, user := range users {
-		output = append(output, map[string]interface{}{
+		output = append(output, map[string]any{
 			"id":         user.ID,
 			"username":   user.Username,
 			"created_at": user.CreatedAt,
@@ -144,7 +146,7 @@ func (rs usersResource) Get(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	respondJSON(w, http.StatusOK, map[string]interface{}{
+	respondJSON(w, http.StatusOK, map[string]any{
 		"id":         user.ID,
 		"username":   user.Username,
 		"created_at": user.CreatedAt,

server/pkg/service/users_test.go

@@ -154,7 +154,7 @@ func TestListUsers_Success(t *testing.T) {
 
 	assert.Equal(t, http.StatusOK, w.Code)
 
-	var response []map[string]interface{}
+	var response []map[string]any
 	if err := json.Unmarshal(w.Body.Bytes(), &response); err != nil {
 		t.Fatal(err)
 	}

server/pkg/service/util.go

@@ -30,7 +30,7 @@ var (
 	usernameRegex = regexp.MustCompile("^[a-z0-9_]+$")
 )
 
-func respondJSON(w http.ResponseWriter, status int, data interface{}) {
+func respondJSON(w http.ResponseWriter, status int, data any) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(status)
 	json.NewEncoder(w).Encode(data)

server/pkg/service/util_test.go

@@ -89,9 +89,18 @@ func TestPasswordEntropyCalculation(t *testing.T) {
 		password string
 		entropy  float64
 	}{
-		{"password", 37.6},
-		{"SecurePassw0rd!123", 103.12},
-		{"aaaaaaaaaaaaaaaa", 9.5},
+		{
+			"password",
+			37.6,
+		},
+		{
+			"SecurePassw0rd!123",
+			103.12,
+		},
+		{
+			"aaaaaaaaaaaaaaaa",
+			9.5,
+		},
 	}
 
 	for _, tt := range tests {