Added tests, shift 'delete'. Fixed overnight shifts, sync, error handling.

handle_kiosk.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"net/http"
 	"strconv"
 )
@@ -87,15 +88,12 @@ func (app *App) handleKioskClaim(w http.ResponseWriter, r *http.Request) {
 		writeError(w, "shift not found", http.StatusNotFound)
 		return
 	}
-	if shift.Capacity > 0 {
-		count, _ := app.shiftAssignedCount(shiftID)
-		if count >= shift.Capacity {
+
+	if err := app.assignShiftWithCapacity(v.ID, shiftID, shift.Capacity); err != nil {
+		if errors.Is(err, errShiftFull) {
 			writeError(w, "shift is full", http.StatusConflict)
 			return
 		}
-	}
-
-	if err := app.assignShift(v.ID, shiftID); err != nil {
 		writeError(w, err.Error(), http.StatusInternalServerError)
 		return
 	}