package taskscheduler

import (
	"context"
	"testing"
	"time"
)

func TestSingleFlightGateBlocksUntilTerminalRelease(t *testing.T) {
	gate := NewSingleFlightGate()
	if err := gate.Acquire(context.Background()); err != nil {
		t.Fatal(err)
	}
	blocked, cancel := context.WithTimeout(context.Background(), 20*time.Millisecond)
	defer cancel()
	if err := gate.Acquire(blocked); err == nil {
		t.Fatal("second task acquired capacity before release")
	}
	gate.Release()
	gate.Release()
	if err := gate.Acquire(context.Background()); err != nil {
		t.Fatal(err)
	}
	blockedAgain, cancelAgain := context.WithTimeout(context.Background(), 20*time.Millisecond)
	defer cancelAgain()
	if err := gate.Acquire(blockedAgain); err == nil {
		t.Fatal("duplicate terminal release increased capacity")
	}
}