// Package clock is a library for testing time related code.  It exports an interface Clock that
// mimics the standard library time package functions.  In production, an implementation that calls
// thru to the standard library is used.  In testing, a Mock clock is used to precisely control and
// intercept time functions.
package clock

import (
	"context"
	"time"
)

type Clock interface {
	// TickerFunc is a convenience function that calls f on the interval d until either the given
	// context expires or f returns an error.  Callers may call Wait() on the returned Waiter to
	// wait until this happens and obtain the error.
	TickerFunc(ctx context.Context, d time.Duration, f func() error, tags ...string) Waiter
	// NewTimer creates a new Timer that will send the current time on its channel after at least
	// duration d.
	NewTimer(d time.Duration, tags ...string) *Timer
}

// Waiter can be waited on for an error.
type Waiter interface {
	Wait(tags ...string) error
}