diff --git a/go.mod b/go.mod
index fc3a96d..282a5c4 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@ module github.com/robindittmar/dttmr-api
 go 1.26
 
 require (
+	github.com/DATA-DOG/go-sqlmock v1.5.2
 	github.com/golang-jwt/jwt/v5 v5.3.1
 	github.com/golang-migrate/migrate/v4 v4.19.1
 	github.com/jackc/pgx/v5 v5.10.0
diff --git a/internal/repository/user_test.go b/internal/repository/user_test.go
new file mode 100644
index 0000000..659674a
--- /dev/null
+++ b/internal/repository/user_test.go
@@ -0,0 +1,189 @@
+package repository
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"regexp"
+	"testing"
+	"time"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/robindittmar/dttmr-api/internal/domain"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestUserRepo_CreateUser(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	assert.NoError(t, err)
+	defer db.Close()
+
+	repo := NewUserRepo(db)
+
+	ctx := context.Background()
+	email := "test@example.com"
+	name := "Test User"
+	passwordHash := "hashedpassword123"
+
+	now := time.Now()
+	expectedUser := &domain.User{
+		ID:        "1",
+		Email:     email,
+		Name:      name,
+		CreatedAt: now,
+	}
+
+	t.Run("success", func(t *testing.T) {
+		mock.ExpectBegin()
+
+		mock.ExpectQuery(`^INSERT INTO users \(email, name, password_hash\) VALUES \(\$1, \$2, \$3\) RETURNING id, created_at$`).
+			WithArgs(email, name, passwordHash).
+			WillReturnRows(sqlmock.NewRows([]string{"id", "created_at"}).AddRow(expectedUser.ID, expectedUser.CreatedAt))
+
+		mock.ExpectCommit()
+
+		user, err := repo.CreateUser(ctx, email, name, passwordHash)
+		assert.NoError(t, err)
+		assert.Equal(t, expectedUser, user)
+		assert.NoError(t, mock.ExpectationsWereMet())
+	})
+
+	t.Run("begin_tx_error", func(t *testing.T) {
+		mock.ExpectBegin().WillReturnError(fmt.Errorf("tx error"))
+
+		user, err := repo.CreateUser(ctx, email, name, passwordHash)
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "begin transaction")
+		assert.Nil(t, user)
+		assert.NoError(t, mock.ExpectationsWereMet())
+	})
+
+	t.Run("insert_error", func(t *testing.T) {
+		mock.ExpectBegin()
+		mock.ExpectQuery(`^INSERT INTO users \(email, name, password_hash\) VALUES \(\$1, \$2, \$3\) RETURNING id, created_at$`).
+			WithArgs(email, name, passwordHash).
+			WillReturnError(fmt.Errorf("insert error"))
+		mock.ExpectRollback()
+
+		user, err := repo.CreateUser(ctx, email, name, passwordHash)
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "failed to insert user")
+		assert.Nil(t, user)
+		assert.NoError(t, mock.ExpectationsWereMet())
+	})
+
+	t.Run("commit_error", func(t *testing.T) {
+		mock.ExpectBegin()
+		mock.ExpectQuery(`^INSERT INTO users \(email, name, password_hash\) VALUES \(\$1, \$2, \$3\) RETURNING id, created_at$`).
+			WithArgs(email, name, passwordHash).
+			WillReturnRows(sqlmock.NewRows([]string{"id", "created_at"}).AddRow(expectedUser.ID, expectedUser.CreatedAt))
+		mock.ExpectCommit().WillReturnError(fmt.Errorf("commit error"))
+
+		user, err := repo.CreateUser(ctx, email, name, passwordHash)
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "commit transaction")
+		assert.Nil(t, user)
+		assert.NoError(t, mock.ExpectationsWereMet())
+	})
+}
+
+func TestUserRepo_CreateUser2(t *testing.T) {
+	email := "test@example.com"
+	name := "Test User"
+	passwordHash := "hashedpassword123"
+	now := time.Now()
+	expectedID := "42"
+
+	insertQuery := regexp.QuoteMeta(
+		"INSERT INTO users (email, name, password_hash) VALUES ($1, $2, $3) RETURNING id, created_at",
+	)
+
+	testCases := []struct {
+		name          string
+		setupMock     func(mock sqlmock.Sqlmock)
+		expectedError string
+	}{
+		{
+			name: "Success: User created perfectly",
+			setupMock: func(mock sqlmock.Sqlmock) {
+				mock.ExpectBegin()
+
+				rows := sqlmock.NewRows([]string{"id", "created_at"}).
+					AddRow(expectedID, now)
+
+				mock.ExpectQuery(insertQuery).
+					WithArgs(email, name, passwordHash).
+					WillReturnRows(rows)
+
+				mock.ExpectCommit()
+			},
+			expectedError: "",
+		},
+		{
+			name: "Failure: Database connection fails on BeginTx",
+			setupMock: func(mock sqlmock.Sqlmock) {
+				mock.ExpectBegin().WillReturnError(errors.New("db connection failed"))
+			},
+			expectedError: "begin transaction: db connection failed",
+		},
+		{
+			name: "Failure: Query fails (e.g., duplicate email)",
+			setupMock: func(mock sqlmock.Sqlmock) {
+				mock.ExpectBegin()
+
+				mock.ExpectQuery(insertQuery).
+					WithArgs(email, name, passwordHash).
+					WillReturnError(errors.New("unique constraint violation"))
+
+				mock.ExpectRollback()
+			},
+			expectedError: "failed to insert user: unique constraint violation",
+		},
+		{
+			name: "Failure: Commit fails (e.g., network timeout)",
+			setupMock: func(mock sqlmock.Sqlmock) {
+				mock.ExpectBegin()
+
+				rows := sqlmock.NewRows([]string{"id", "created_at"}).
+					AddRow(expectedID, now)
+
+				mock.ExpectQuery(insertQuery).
+					WithArgs(email, name, passwordHash).
+					WillReturnRows(rows)
+
+				mock.ExpectCommit().WillReturnError(errors.New("commit timeout"))
+			},
+			expectedError: "commit transaction: commit timeout",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			db, mock, err := sqlmock.New()
+			require.NoError(t, err)
+			defer db.Close()
+
+			tc.setupMock(mock)
+
+			repo := NewUserRepo(db)
+
+			user, err := repo.CreateUser(context.Background(), email, name, passwordHash)
+
+			if tc.expectedError != "" {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), tc.expectedError)
+				assert.Nil(t, user)
+			} else {
+				require.NoError(t, err)
+				require.NotNil(t, user)
+				assert.Equal(t, expectedID, user.ID)
+				assert.Equal(t, email, user.Email)
+				assert.Equal(t, name, user.Name)
+				assert.Equal(t, now, user.CreatedAt)
+			}
+
+			assert.NoError(t, mock.ExpectationsWereMet())
+		})
+	}
+}