summaryrefslogtreecommitdiff
path: root/test/chan/select3.go
diff options
context:
space:
mode:
Diffstat (limited to 'test/chan/select3.go')
-rw-r--r--test/chan/select3.go224
1 files changed, 0 insertions, 224 deletions
diff --git a/test/chan/select3.go b/test/chan/select3.go
deleted file mode 100644
index b4e8f8e4b..000000000
--- a/test/chan/select3.go
+++ /dev/null
@@ -1,224 +0,0 @@
-// $G $D/$F.go && $L $F.$A && ./$A.out
-
-// Copyright 2010 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.
-
-// Tests verifying the semantics of the select statement
-// for basic empty/non-empty cases.
-
-package main
-
-import "time"
-
-const always = "function did not"
-const never = "function did"
-
-
-func unreachable() {
- panic("control flow shouldn't reach here")
-}
-
-
-// Calls f and verifies that f always/never panics depending on signal.
-func testPanic(signal string, f func()) {
- defer func() {
- s := never
- if recover() != nil {
- s = always // f panicked
- }
- if s != signal {
- panic(signal + " panic")
- }
- }()
- f()
-}
-
-
-// Calls f and empirically verifies that f always/never blocks depending on signal.
-func testBlock(signal string, f func()) {
- c := make(chan string)
- go func() {
- f()
- c <- never // f didn't block
- }()
- go func() {
- time.Sleep(1e8) // 0.1s seems plenty long
- c <- always // f blocked always
- }()
- if <-c != signal {
- panic(signal + " block")
- }
-}
-
-
-func main() {
- const async = 1 // asynchronous channels
- var nilch chan int
- closedch := make(chan int)
- close(closedch)
-
- // sending/receiving from a nil channel outside a select panics
- testPanic(always, func() {
- nilch <- 7
- })
- testPanic(always, func() {
- <-nilch
- })
-
- // sending/receiving from a nil channel inside a select never panics
- testPanic(never, func() {
- select {
- case nilch <- 7:
- unreachable()
- default:
- }
- })
- testPanic(never, func() {
- select {
- case <-nilch:
- unreachable()
- default:
- }
- })
-
- // sending to an async channel with free buffer space never blocks
- testBlock(never, func() {
- ch := make(chan int, async)
- ch <- 7
- })
-
- // receiving from a closed channel never blocks
- testBlock(never, func() {
- for i := 0; i < 10; i++ {
- if <-closedch != 0 {
- panic("expected zero value when reading from closed channel")
- }
- if x, ok := <-closedch; x != 0 || ok {
- println("closedch:", x, ok)
- panic("expected 0, false from closed channel")
- }
- }
- })
-
- // sending to a closed channel panics.
- testPanic(always, func() {
- closedch <- 7
- })
-
- // receiving from a non-ready channel always blocks
- testBlock(always, func() {
- ch := make(chan int)
- <-ch
- })
-
- // empty selects always block
- testBlock(always, func() {
- select {
- }
- })
-
- // selects with only nil channels always block
- testBlock(always, func() {
- select {
- case <-nilch:
- unreachable()
- }
- })
- testBlock(always, func() {
- select {
- case nilch <- 7:
- unreachable()
- }
- })
- testBlock(always, func() {
- select {
- case <-nilch:
- unreachable()
- case nilch <- 7:
- unreachable()
- }
- })
-
- // selects with non-ready non-nil channels always block
- testBlock(always, func() {
- ch := make(chan int)
- select {
- case <-ch:
- unreachable()
- }
- })
-
- // selects with default cases don't block
- testBlock(never, func() {
- select {
- default:
- }
- })
- testBlock(never, func() {
- select {
- case <-nilch:
- unreachable()
- default:
- }
- })
- testBlock(never, func() {
- select {
- case nilch <- 7:
- unreachable()
- default:
- }
- })
-
- // selects with ready channels don't block
- testBlock(never, func() {
- ch := make(chan int, async)
- select {
- case ch <- 7:
- default:
- unreachable()
- }
- })
- testBlock(never, func() {
- ch := make(chan int, async)
- ch <- 7
- select {
- case <-ch:
- default:
- unreachable()
- }
- })
-
- // selects with closed channels behave like ordinary operations
- testBlock(never, func() {
- select {
- case <-closedch:
- }
- })
- testBlock(never, func() {
- select {
- case x := <-closedch:
- _ = x
- }
- })
- testBlock(never, func() {
- select {
- case x, ok := <-closedch:
- _, _ = x, ok
- }
- })
- testPanic(always, func() {
- select {
- case closedch <- 7:
- }
- })
-
- // select should not get confused if it sees itself
- testBlock(always, func() {
- c := make(chan int)
- select {
- case c <- 1:
- case <-c:
- }
- })
-}