feat(bookings): add comprehensive overlap detection tests

Covers admin create, user edit, auto-approve, service duration extension, reserve, admin reserve, admin reschedule, confirm, and admin approve edit request — all with overlap edge cases. Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
2026-06-21 21:01:17 +01:00
parent 88892059c5
commit e23cc3cc6f
1 changed files with 941 additions and 0 deletions
@@ -0,0 +1,941 @@
+//go:build test && dev
+// +build test,dev
+
+package bookings
+
+import (
+	"context"
+	"net/http"
+	"testing"
+	"time"
+
+	"crussell/db"
+	"crussell/mw"
+	"crussell/testutils"
+	"crussell/testutils/fixtures"
+	"crussell/testutils/jwt"
+)
+
+// ============================================================================
+// Helpers
+// ============================================================================
+
+// weekdayTime returns a far-future time on the given weekday at hour:00 UTC.
+// Ensures at least 2 weeks out so all time-window checks (deposits, advance)
+// pass without interference.
+func weekdayTime(weekday time.Weekday, hour int) time.Time {
+	now := time.Now().UTC()
+	daysAhead := int(weekday) - int(now.Weekday())
+	if daysAhead <= 0 {
+		daysAhead += 7
+	}
+	// Push far enough forward that advance-window / deposit checks don't interfere
+	daysAhead += 21
+	result := now.AddDate(0, 0, daysAhead)
+	return time.Date(result.Year(), result.Month(), result.Day(), hour, 0, 0, 0, time.UTC)
+}
+
+// durationMinutes returns the duration_minutes for a given service ID from the tx.
+func durationMinutes(t *testing.T, ctx context.Context, tx db.Querier, serviceID string) int {
+	t.Helper()
+	var d int
+	if err := tx.QueryRow(ctx, "SELECT duration_minutes FROM services WHERE id = $1", serviceID).Scan(&d); err != nil {
+		t.Fatalf("failed to get service duration: %v", err)
+	}
+	return d
+}
+
+// ============================================================================
+// AdminCreateBookingForUserHandler — overlap detection
+// ============================================================================
+
+// TestAdminCreateBooking_OverlapWithConfirmed verifies that creating a booking
+// at a time that overlaps an existing confirmed booking returns 409.
+func TestAdminCreateBooking_OverlapWithConfirmed(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	adminID, err := fixtures.CreateTestAdminUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create admin: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	// Create an existing confirmed booking
+	existingID, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create existing booking: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", existingID)
+	if err != nil {
+		t.Fatalf("failed to confirm existing booking: %v", err)
+	}
+
+	// Try to create a new booking overlapping the existing one (starts 15 min
+	// after the existing booking starts but before it ends).
+	overlapTime := baseTime.Add(time.Duration(dur/2) * time.Minute)
+
+	body := AdminCreateBookingForUserRequest{
+		UserID:     userID,
+		StartTime:  overlapTime,
+		ServiceIDs: []string{serviceID},
+	}
+
+	w := serveChiHandler(AdminCreateBookingForUserHandler, "POST", "/", "/", body,
+		func(baseCtx context.Context) context.Context {
+			baseCtx = context.WithValue(baseCtx, mw.UserRoleKey, "admin")
+			baseCtx = context.WithValue(baseCtx, mw.UserIDKey, adminID)
+			return db.ContextWithTx(baseCtx, db.TxFromContext(ctx))
+		})
+
+	if w.Code != http.StatusConflict {
+		t.Errorf("expected 409 for overlapping booking, got %d. body: %s", w.Code, w.Body.String())
+	}
+
+	// Verify the existing booking was NOT evicted (no pending_release eviction
+	// since the existing booking is confirmed, not pending_release).
+	var status string
+	err = tx.QueryRow(ctx, "SELECT status FROM bookings WHERE id = $1", existingID).Scan(&status)
+	if err != nil {
+		t.Fatalf("failed to query existing booking: %v", err)
+	}
+	if status != "confirmed" {
+		t.Errorf("expected existing booking to remain 'confirmed', got %q", status)
+	}
+}
+
+// TestAdminCreateBooking_AdjacentBooking_NoOverlap verifies that creating a
+// booking at the exact end of an existing booking (adjacent, no gap) is allowed.
+func TestAdminCreateBooking_AdjacentBooking_NoOverlap(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	adminID, err := fixtures.CreateTestAdminUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create admin: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	// Create an existing confirmed booking [10:00, 10:00+dur)
+	existingID, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create existing booking: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", existingID)
+	if err != nil {
+		t.Fatalf("failed to confirm existing booking: %v", err)
+	}
+
+	// Create a new booking starting exactly when the existing one ends (adjacent,
+	// no overlap).
+	adjacentTime := baseTime.Add(time.Duration(dur) * time.Minute)
+
+	body := AdminCreateBookingForUserRequest{
+		UserID:     userID,
+		StartTime:  adjacentTime,
+		ServiceIDs: []string{serviceID},
+	}
+
+	w := serveChiHandler(AdminCreateBookingForUserHandler, "POST", "/", "/", body,
+		func(baseCtx context.Context) context.Context {
+			baseCtx = context.WithValue(baseCtx, mw.UserRoleKey, "admin")
+			baseCtx = context.WithValue(baseCtx, mw.UserIDKey, adminID)
+			return db.ContextWithTx(baseCtx, db.TxFromContext(ctx))
+		})
+
+	if w.Code != http.StatusCreated && w.Code != http.StatusOK {
+		t.Errorf("expected 200/201 for adjacent (non-overlapping) booking, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// TestAdminCreateBooking_ExactSameStartTime verifies that creating a booking
+// at the exact same start time as an existing booking is rejected.
+func TestAdminCreateBooking_ExactSameStartTime(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	adminID, err := fixtures.CreateTestAdminUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create admin: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	existingID, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create existing booking: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", existingID)
+	if err != nil {
+		t.Fatalf("failed to confirm existing booking: %v", err)
+	}
+
+	// Same exact start time
+	body := AdminCreateBookingForUserRequest{
+		UserID:     userID,
+		StartTime:  baseTime,
+		ServiceIDs: []string{serviceID},
+	}
+
+	w := serveChiHandler(AdminCreateBookingForUserHandler, "POST", "/", "/", body,
+		func(baseCtx context.Context) context.Context {
+			baseCtx = context.WithValue(baseCtx, mw.UserRoleKey, "admin")
+			baseCtx = context.WithValue(baseCtx, mw.UserIDKey, adminID)
+			return db.ContextWithTx(baseCtx, db.TxFromContext(ctx))
+		})
+
+	if w.Code != http.StatusConflict {
+		t.Errorf("expected 409 for same start time, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// ============================================================================
+// EditBookingHandler - user-facing edit overlap detection
+// ============================================================================
+
+// TestEditBooking_OverlapWithExisting verifies that editing a booking to an
+// overlapping time slot returns 409.
+func TestEditBooking_OverlapWithExisting(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	// Disable deposits for this user so the handler doesn't check deposit limits
+	_, err = tx.Exec(ctx, "UPDATE users SET deposits_required = 0 WHERE id = $1", userID)
+	if err != nil {
+		t.Fatalf("failed to set deposits_required: %v", err)
+	}
+
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+	token := jwt.GenerateUserToken(userID)
+
+	// Create booking A (the one we're editing) at [10:00, 10:00+dur)
+	bookingA, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create booking A: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingA)
+	if err != nil {
+		t.Fatalf("failed to confirm booking A: %v", err)
+	}
+
+	// Create booking B at [12:00, 12:00+dur) — far enough away to not interfere initially
+	farTime := baseTime.Add(2 * time.Hour)
+	bookingB, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, farTime)
+	if err != nil {
+		t.Fatalf("failed to create booking B: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingB)
+	if err != nil {
+		t.Fatalf("failed to confirm booking B: %v", err)
+	}
+
+	// Now edit booking A to a time that overlaps booking B.
+	// Move it to [11:30, 11:30+dur) — booking B is at [12:00, 12:00+dur), so
+	// 11:30+dur > 12:00 means overlap.
+	overlapTime := farTime.Add(-time.Duration(dur/2) * time.Minute)
+
+	handler := http.HandlerFunc(EditBookingHandler)
+	w := makeRequest(handler, "PUT", "/api/bookings/"+bookingA, map[string]interface{}{
+		"start_time":  overlapTime.Format(time.RFC3339),
+		"service_ids": []string{serviceID},
+	}, token, ctx)
+
+	if w.Code != http.StatusConflict {
+		t.Errorf("expected 409 for overlapping edit, got %d. body: %s", w.Code, w.Body.String())
+	}
+
+	// Verify booking A was NOT updated (still at original time)
+	var actualStart time.Time
+	err = tx.QueryRow(ctx, "SELECT start_time FROM bookings WHERE id = $1", bookingA).Scan(&actualStart)
+	if err != nil {
+		t.Fatalf("failed to query booking A: %v", err)
+	}
+	if !actualStart.Equal(baseTime) {
+		t.Errorf("expected booking A start_time to remain %v, got %v", baseTime, actualStart)
+	}
+}
+
+// TestEditBooking_NonOverlappingEdit_Succeeds verifies that editing a booking
+// to a non-overlapping time succeeds.
+func TestEditBooking_NonOverlappingEdit_Succeeds(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE users SET deposits_required = 0 WHERE id = $1", userID)
+	if err != nil {
+		t.Fatalf("failed to set deposits_required: %v", err)
+	}
+
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+	newTime := baseTime.Add(24 * time.Hour) // Next day, far from any conflict
+	token := jwt.GenerateUserToken(userID)
+
+	bookingID, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create booking: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingID)
+	if err != nil {
+		t.Fatalf("failed to confirm booking: %v", err)
+	}
+
+	_ = dur
+
+	handler := http.HandlerFunc(EditBookingHandler)
+	w := makeRequest(handler, "PUT", "/api/bookings/"+bookingID, map[string]interface{}{
+		"start_time":  newTime.Format(time.RFC3339),
+		"service_ids": []string{serviceID},
+	}, token, ctx)
+
+	if w.Code != http.StatusOK {
+		t.Errorf("expected 200 for non-overlapping edit, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// ============================================================================
+// RequestEditHandler — auto-approve path overlap detection
+// ============================================================================
+
+// TestRequestEditHandler_AutoApprove_OverlapDetected verifies that the
+// auto-approve path rejects a request that would create an overlap.
+// Requests with new_start_time and >48h to the event trigger auto-approval
+// which runs the overlap check inline.
+func TestRequestEditHandler_AutoApprove_OverlapDetected(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE users SET deposits_required = 0 WHERE id = $1", userID)
+	if err != nil {
+		t.Fatalf("failed to set deposits_required: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+	token := jwt.GenerateUserToken(userID)
+
+	// Booking A — user's existing confirmed booking at [10:00, 10:00+dur)
+	bookingA, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create booking A: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingA)
+	if err != nil {
+		t.Fatalf("failed to confirm booking A: %v", err)
+	}
+
+	// Booking B — at a far-away time (so auto-approve triggers when we set
+	// new_start_time on an existing confirmed booking >48h out)
+	bookingBTime := baseTime.Add(48 * time.Hour)
+	bookingB, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, bookingBTime)
+	if err != nil {
+		t.Fatalf("failed to create booking B: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingB)
+	if err != nil {
+		t.Fatalf("failed to confirm booking B: %v", err)
+	}
+
+	// Submit edit request with a new_start_time that overlaps A.
+	// Since the edit request is >48h before the booking event, the auto-approve
+	// path runs the overlap check and should reject with 409.
+	overlapTime := baseTime.Add(time.Duration(dur/2) * time.Minute)
+
+	handler := http.HandlerFunc(RequestEditHandler)
+	w := makeRequest(handler, "POST", "/api/bookings/"+bookingB+"/edit-request", map[string]interface{}{
+		"new_start_time": overlapTime.Format(time.RFC3339),
+	}, token, ctx)
+
+	if w.Code != http.StatusConflict {
+		t.Errorf("expected 409 for overlapping auto-approve, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// ============================================================================
+// UpdateBookingServicesHandler — extending duration into existing booking
+// ============================================================================
+
+// TestUpdateBookingServices_ExtendOverlapsExisting verifies that extending a
+// booking's duration (by adding a second service) into an existing booking's
+// slot returns 409.
+func TestUpdateBookingServices_ExtendOverlapsExisting(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	adminID, err := fixtures.CreateTestAdminUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create admin: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	// Booking A — starts at 10:00, duration = dur (ends at 10:00+dur)
+	bookingA, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create booking A: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingA)
+	if err != nil {
+		t.Fatalf("failed to confirm booking A: %v", err)
+	}
+
+	// Booking B — starts exactly when A ends (adjacent, no overlap initially)
+	adjacentTime := baseTime.Add(time.Duration(dur) * time.Minute)
+	bookingB, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, adjacentTime)
+	if err != nil {
+		t.Fatalf("failed to create booking B: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingB)
+	if err != nil {
+		t.Fatalf("failed to confirm booking B: %v", err)
+	}
+
+	// Create a second service with short duration (30 min) that, when added to
+	// A, would make A extend INTO B's slot.
+	shortSvcID, err := fixtures.CreateTestServiceWithDuration(tx, 30)
+	if err != nil {
+		t.Fatalf("failed to create short service: %v", err)
+	}
+
+	// Try to add the second service to booking A — this extends A's duration
+	// to dur+30, which exceeds the gap to booking B.
+	w := serveChiHandler(UpdateBookingServicesHandler, "PUT", "/"+bookingA, "/{id}", map[string]interface{}{
+		"service_ids": []string{serviceID, shortSvcID},
+	}, func(baseCtx context.Context) context.Context {
+		baseCtx = context.WithValue(baseCtx, mw.UserRoleKey, "admin")
+		baseCtx = context.WithValue(baseCtx, mw.UserIDKey, adminID)
+		return db.ContextWithTx(baseCtx, db.TxFromContext(ctx))
+	})
+
+	if w.Code != http.StatusConflict {
+		t.Errorf("expected 409 for extending into existing booking, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// TestUpdateBookingServices_ExtendNoOverlap_Succeeds verifies that extending a
+// booking's duration without overlapping another booking succeeds.
+func TestUpdateBookingServices_ExtendNoOverlap_Succeeds(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	adminID, err := fixtures.CreateTestAdminUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create admin: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	// Booking A — starts at 10:00
+	bookingA, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create booking A: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingA)
+	if err != nil {
+		t.Fatalf("failed to confirm booking A: %v", err)
+	}
+
+	// Booking B — starts 3 hours later (plenty of room)
+	farTime := baseTime.Add(3 * time.Hour)
+	bookingB, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, farTime)
+	if err != nil {
+		t.Fatalf("failed to create booking B: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingB)
+	if err != nil {
+		t.Fatalf("failed to confirm booking B: %v", err)
+	}
+
+	_ = dur
+
+	// Create a second service with 30 min duration — A would be dur+30,
+	// which still leaves plenty of gap before B.
+	shortSvcID, err := fixtures.CreateTestServiceWithDuration(tx, 30)
+	if err != nil {
+		t.Fatalf("failed to create short service: %v", err)
+	}
+
+	w := serveChiHandler(UpdateBookingServicesHandler, "PUT", "/"+bookingA, "/{id}", map[string]interface{}{
+		"service_ids": []string{serviceID, shortSvcID},
+	}, func(baseCtx context.Context) context.Context {
+		baseCtx = context.WithValue(baseCtx, mw.UserRoleKey, "admin")
+		baseCtx = context.WithValue(baseCtx, mw.UserIDKey, adminID)
+		return db.ContextWithTx(baseCtx, db.TxFromContext(ctx))
+	})
+
+	if w.Code != http.StatusOK {
+		t.Errorf("expected 200 for extending without overlap, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// ============================================================================
+// ReserveSlotHandler — overlap detection (existing test was checking for
+// regression, this strengthens coverage)
+// ============================================================================
+
+// TestReserveSlot_OverlapWithExistingBooking confirms that the reserve endpoint
+// returns 409 when the requested slot overlaps a confirmed booking.
+func TestReserveSlot_OverlapWithExistingBooking(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	_, err = tx.Exec(ctx, `
+		INSERT INTO bookings (user_id, start_time, status, deposit_required)
+		VALUES ($1, $2, 'confirmed', false)
+	`, userID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create booking: %v", err)
+	}
+
+	w := makeReserveRequest(ctx, "POST", "/api/bookings/reserve", ReserveSlotRequest{
+		StartTime:  baseTime,
+		ServiceIDs: []string{serviceID},
+	}, "")
+	if w.Code != http.StatusConflict {
+		t.Errorf("expected 409 for overlapping booking, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// ============================================================================
+// AdminReserveSlotHandler — overlap detection
+// ============================================================================
+
+// TestAdminReserveSlot_OverlapWithExistingBooking verifies that admin reserve
+// returns 409 when the slot overlaps a confirmed booking.
+func TestAdminReserveSlot_OverlapWithExistingBooking(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	_, err = tx.Exec(ctx, `
+		INSERT INTO bookings (user_id, start_time, status)
+		VALUES ($1, $2, 'confirmed')
+	`, userID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create booking: %v", err)
+	}
+
+	w := serveChiHandler(AdminReserveSlotHandler, "POST", "/", "/", AdminReserveSlotRequest{
+		StartTime:       baseTime,
+		ServiceIDs:      []string{serviceID},
+		ReservationType: "callin",
+	}, func(baseCtx context.Context) context.Context {
+		baseCtx = context.WithValue(baseCtx, mw.UserRoleKey, "admin")
+		baseCtx = context.WithValue(baseCtx, mw.UserIDKey, userID)
+		return db.ContextWithTx(baseCtx, db.TxFromContext(ctx))
+	})
+
+	if w.Code != http.StatusConflict {
+		t.Errorf("expected 409 for overlapping admin reserve, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// ============================================================================
+// AdminRescheduleBookingHandler — overlap detection
+// ============================================================================
+
+// TestAdminRescheduleBooking_OverlapWithConfirmed verifies that rescheduling
+// a booking to an overlapping time returns 409.
+func TestAdminRescheduleBooking_OverlapWithConfirmed(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	adminID, err := fixtures.CreateTestAdminUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create admin: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	// Booking A — occupies [10:00, 10:00+dur)
+	bookingA, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create booking A: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingA)
+	if err != nil {
+		t.Fatalf("failed to confirm booking A: %v", err)
+	}
+
+	// Booking B — later slot, will be rescheduled INTO A's slot
+	bookingBTime := baseTime.Add(48 * time.Hour)
+	bookingB, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, bookingBTime)
+	if err != nil {
+		t.Fatalf("failed to create booking B: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingB)
+	if err != nil {
+		t.Fatalf("failed to confirm booking B: %v", err)
+	}
+
+	// Try to reschedule B into A's slot (overlap)
+	overlapTime := baseTime.Add(time.Duration(dur/2) * time.Minute)
+
+	body := map[string]interface{}{
+		"start_time": overlapTime.Format(time.RFC3339),
+	}
+
+	w := serveChiHandler(AdminRescheduleBookingHandler, "PUT", "/"+bookingB+"/reschedule", "/{id}/reschedule", body,
+		func(baseCtx context.Context) context.Context {
+			baseCtx = context.WithValue(baseCtx, mw.UserRoleKey, "admin")
+			baseCtx = context.WithValue(baseCtx, mw.UserIDKey, adminID)
+			return db.ContextWithTx(baseCtx, db.TxFromContext(ctx))
+		})
+
+	if w.Code != http.StatusConflict {
+		t.Errorf("expected 409 for reschedule overlapping booking, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// ============================================================================
+// ConfirmBookingHandler — overlap detection
+// ============================================================================
+
+// TestConfirmBooking_OverlapWithConfirmed verifies that confirming a booking
+// that would overlap an existing confirmed booking returns 409.
+func TestConfirmBooking_OverlapWithConfirmed(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	adminID, err := fixtures.CreateTestAdminUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create admin: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	// Booking A — confirmed, occupies [10:00, 10:00+dur)
+	bookingA, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create booking A: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingA)
+	if err != nil {
+		t.Fatalf("failed to confirm booking A: %v", err)
+	}
+
+	// Booking B — pending, at the same time (would overlap if confirmed)
+	bookingB, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime.Add(15*time.Minute))
+	if err != nil {
+		t.Fatalf("failed to create booking B: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'pending' WHERE id = $1", bookingB)
+	if err != nil {
+		t.Fatalf("failed to set booking B to pending: %v", err)
+	}
+
+	_ = dur
+
+	// Confirm booking B — should be rejected because it would overlap A
+	w := serveChiHandler(ConfirmBookingHandler, "POST", "/"+bookingB+"/confirm", "/{id}/confirm", map[string]interface{}{},
+		func(baseCtx context.Context) context.Context {
+			baseCtx = context.WithValue(baseCtx, mw.UserRoleKey, "admin")
+			baseCtx = context.WithValue(baseCtx, mw.UserIDKey, adminID)
+			return db.ContextWithTx(baseCtx, db.TxFromContext(ctx))
+		})
+
+	if w.Code != http.StatusConflict {
+		t.Errorf("expected 409 for confirm overlapping booking, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// TestConfirmBooking_NoOverlap_Succeeds verifies that confirming a non-overlapping
+// pending booking succeeds.
+func TestConfirmBooking_NoOverlap_Succeeds(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	adminID, err := fixtures.CreateTestAdminUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create admin: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	// Existing confirmed booking
+	existingID, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create existing booking: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", existingID)
+	if err != nil {
+		t.Fatalf("failed to confirm existing booking: %v", err)
+	}
+
+	// Pending booking at a non-overlapping time (adjacent, exactly when A ends)
+	pendingStart := baseTime.Add(time.Duration(dur) * time.Minute)
+	pendingID, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, pendingStart)
+	if err != nil {
+		t.Fatalf("failed to create pending booking: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'pending' WHERE id = $1", pendingID)
+	if err != nil {
+		t.Fatalf("failed to set pending: %v", err)
+	}
+
+	w := serveChiHandler(ConfirmBookingHandler, "POST", "/"+pendingID+"/confirm", "/{id}/confirm", map[string]interface{}{},
+		func(baseCtx context.Context) context.Context {
+			baseCtx = context.WithValue(baseCtx, mw.UserRoleKey, "admin")
+			baseCtx = context.WithValue(baseCtx, mw.UserIDKey, adminID)
+			return db.ContextWithTx(baseCtx, db.TxFromContext(ctx))
+		})
+
+	if w.Code != http.StatusOK {
+		t.Errorf("expected 200 for confirming non-overlapping booking, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// ============================================================================
+// AdminApproveEditRequestHandler — overlap at approval time
+// ============================================================================
+
+// TestAdminApproveEditRequest_OverlapWithBooking is already tested in
+// edit_requests_test.go:1607. This test re-verifies the same scenario with
+// the updated handler to guard against regression.
+func TestAdminApproveEditRequest_OverlapWithBooking_Regression(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE users SET deposits_required = 0 WHERE id = $1", userID)
+	if err != nil {
+		t.Fatalf("failed to set deposits_required: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+	dur := durationMinutes(t, ctx, tx, serviceID)
+
+	// Use <48h from now so RequestEditHandler does NOT auto-approve
+	nearTime := time.Now().Add(40 * time.Hour)
+	nearTime = time.Date(nearTime.Year(), nearTime.Month(), nearTime.Day(), nearTime.Hour(), 0, 0, 0, nearTime.Location())
+	switch nearTime.Weekday() {
+	case time.Sunday:
+		nearTime = nearTime.AddDate(0, 0, 2)
+	case time.Monday:
+		nearTime = nearTime.AddDate(0, 0, 1)
+	}
+
+	token := jwt.GenerateUserToken(userID)
+
+	bookingA, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, nearTime)
+	if err != nil {
+		t.Fatalf("failed to create booking A: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingA)
+	if err != nil {
+		t.Fatalf("failed to confirm booking A: %v", err)
+	}
+
+	bookingBTime := nearTime.Add(2 * time.Hour)
+	bookingB, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, bookingBTime)
+	if err != nil {
+		t.Fatalf("failed to create booking B: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'confirmed' WHERE id = $1", bookingB)
+	if err != nil {
+		t.Fatalf("failed to confirm booking B: %v", err)
+	}
+
+	overlapTime := nearTime.Add(time.Duration(dur/2) * time.Minute)
+	handler := http.HandlerFunc(RequestEditHandler)
+	w := makeRequest(handler, "POST", "/api/bookings/"+bookingB+"/edit-request",
+		map[string]interface{}{
+			"new_start_time": overlapTime.Format(time.RFC3339),
+		}, token, ctx)
+	if w.Code != http.StatusCreated {
+		t.Fatalf("failed to create edit request: %d. body: %s", w.Code, w.Body.String())
+	}
+
+	editRequestID := getEditRequestIDFromDB(t, ctx, tx, bookingB)
+
+	approveHandler := http.HandlerFunc(AdminApproveEditRequestHandler)
+	w = serveAdminHandler(approveHandler, "POST",
+		"/api/admin/bookings/"+bookingB+"/edit-requests/"+editRequestID+"/approve",
+		"/api/admin/bookings/{id}/edit-requests/{request_id}/approve", nil, ctx)
+
+	if w.Code != http.StatusConflict {
+		t.Errorf("expected 409 for approve overlapping request, got %d. body: %s", w.Code, w.Body.String())
+	}
+}
+
+// ============================================================================
+// Bookings status evolution — overlap edge cases
+// ============================================================================
+
+// TestAdminCreateBooking_OverlapWithCancelled_Allowed verifies that creating a
+// booking overlapping a cancelled booking is allowed (cancelled bookings are
+// excluded from overlap checks).
+func TestAdminCreateBooking_OverlapWithCancelled_Allowed(t *testing.T) {
+	t.Parallel()
+	ctx, tx := testutils.SetupTestTx(t)
+
+	userID, err := fixtures.CreateTestUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create user: %v", err)
+	}
+	adminID, err := fixtures.CreateTestAdminUser(tx)
+	if err != nil {
+		t.Fatalf("failed to create admin: %v", err)
+	}
+	serviceID, err := fixtures.CreateTestService(tx)
+	if err != nil {
+		t.Fatalf("failed to create service: %v", err)
+	}
+
+	baseTime := weekdayTime(time.Wednesday, 10)
+
+	cancelledID, err := fixtures.CreateTestBookingAtTime(tx, userID, serviceID, baseTime)
+	if err != nil {
+		t.Fatalf("failed to create booking: %v", err)
+	}
+	_, err = tx.Exec(ctx, "UPDATE bookings SET status = 'client_cancelled' WHERE id = $1", cancelledID)
+	if err != nil {
+		t.Fatalf("failed to set client_cancelled: %v", err)
+	}
+
+	// Creating a booking overlapping a cancelled one should be OK
+	body := AdminCreateBookingForUserRequest{
+		UserID:     userID,
+		StartTime:  baseTime,
+		ServiceIDs: []string{serviceID},
+	}
+
+	w := serveChiHandler(AdminCreateBookingForUserHandler, "POST", "/", "/", body,
+		func(baseCtx context.Context) context.Context {
+			baseCtx = context.WithValue(baseCtx, mw.UserRoleKey, "admin")
+			baseCtx = context.WithValue(baseCtx, mw.UserIDKey, adminID)
+			return db.ContextWithTx(baseCtx, db.TxFromContext(ctx))
+		})
+
+	if w.Code != http.StatusCreated && w.Code != http.StatusOK {
+		t.Errorf("expected 200/201 for overlapping completed booking, got %d. body: %s", w.Code, w.Body.String())
+	}
+}