// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package testing

func TestTestContext(t *T) {
	const (
		add1 = 0
		done = 1
	)
	// After each of the calls are applied to the context, the
	type call struct {
		typ int // run or done
		// result from applying the call
		running int
		waiting int
		started bool
	}
	testCases := []struct {
		max int
		run []call
	}{{
		max: 1,
		run: []call{
			{typ: add1, running: 1, waiting: 0, started: true},
			{typ: done, running: 0, waiting: 0, started: false},
		},
	}, {
		max: 1,
		run: []call{
			{typ: add1, running: 1, waiting: 0, started: true},
			{typ: add1, running: 1, waiting: 1, started: false},
			{typ: done, running: 1, waiting: 0, started: true},
			{typ: done, running: 0, waiting: 0, started: false},
			{typ: add1, running: 1, waiting: 0, started: true},
		},
	}, {
		max: 3,
		run: []call{
			{typ: add1, running: 1, waiting: 0, started: true},
			{typ: add1, running: 2, waiting: 0, started: true},
			{typ: add1, running: 3, waiting: 0, started: true},
			{typ: add1, running: 3, waiting: 1, started: false},
			{typ: add1, running: 3, waiting: 2, started: false},
			{typ: add1, running: 3, waiting: 3, started: false},
			{typ: done, running: 3, waiting: 2, started: true},
			{typ: add1, running: 3, waiting: 3, started: false},
			{typ: done, running: 3, waiting: 2, started: true},
			{typ: done, running: 3, waiting: 1, started: true},
			{typ: done, running: 3, waiting: 0, started: true},
			{typ: done, running: 2, waiting: 0, started: false},
			{typ: done, running: 1, waiting: 0, started: false},
			{typ: done, running: 0, waiting: 0, started: false},
		},
	}}
	for i, tc := range testCases {
		ctx := &testContext{
			startParallel: make(chan bool),
			maxParallel:   tc.max,
		}
		for j, call := range tc.run {
			doCall := func(f func()) chan bool {
				done := make(chan bool)
				go func() {
					f()
					done <- true
				}()
				return done
			}
			started := false
			switch call.typ {
			case add1:
				signal := doCall(ctx.waitParallel)
				select {
				case <-signal:
					started = true
				case ctx.startParallel <- true:
					<-signal
				}
			case done:
				signal := doCall(ctx.release)
				select {
				case <-signal:
				case <-ctx.startParallel:
					started = true
					<-signal
				}
			}
			if started != call.started {
				t.Errorf("%d:%d:started: got %v; want %v", i, j, started, call.started)
			}
			if ctx.running != call.running {
				t.Errorf("%d:%d:running: got %v; want %v", i, j, ctx.running, call.running)
			}
			if ctx.numWaiting != call.waiting {
				t.Errorf("%d:%d:waiting: got %v; want %v", i, j, ctx.numWaiting, call.waiting)
			}
		}
	}
}