add test for close/closed, fix a few implementation bugs.

R=ken
OCL=26664
CL=26664

test/closedchan.go

diff --git a/test/closedchan.go b/test/closedchan.go
new file mode 100644
index 0000000..4ab12c7
--- /dev/null
+++ b/test/closedchan.go
@@ -0,0 +1,197 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2009 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.
+
+// Test close(c), closed(c).
+//
+// TODO(rsc): Doesn't check behavior of close(c) when there
+// are blocked senders/receivers.
+
+package main
+
+type Chan interface {
+	Send(int);
+	Nbsend(int) bool;
+	Recv() int;
+	Nbrecv() (int, bool);
+	Close();
+	Closed() bool;
+	Impl() string;
+}
+
+// direct channel operations
+type XChan chan int
+func (c XChan) Send(x int) {
+	c <- x
+}
+
+func (c XChan) Nbsend(x int) bool {
+	return c <- x;
+}
+
+func (c XChan) Recv() int {
+	return <-c
+}
+
+func (c XChan) Nbrecv() (int, bool) {
+	x, ok := <-c;
+	return x, ok;
+}
+
+func (c XChan) Close() {
+	close(c)
+}
+
+func (c XChan) Closed() bool {
+	return closed(c)
+}
+
+func (c XChan) Impl() string {
+	return "(<- operator)"
+}
+
+// indirect operations via select
+type SChan chan int
+func (c SChan) Send(x int) {
+	select {
+	case c <- x:
+	}
+}
+
+func (c SChan) Nbsend(x int) bool {
+	select {
+	case c <- x:
+		return true;
+	default:
+		return false;
+	}
+	panic("nbsend");
+}
+
+func (c SChan) Recv() int {
+	select {
+	case x := <-c:
+		return x;
+	}
+	panic("recv");
+}
+
+func (c SChan) Nbrecv() (int, bool) {
+	select {
+	case x := <-c:
+		return x, true;
+	default:
+		return 0, false;
+	}
+	panic("nbrecv");
+}
+
+func (c SChan) Close() {
+	close(c)
+}
+
+func (c SChan) Closed() bool {
+	return closed(c)
+}
+
+func (c SChan) Impl() string {
+	return "(select)";
+}
+
+func test1(c Chan) {
+	// not closed until the close signal (a zero value) has been received.
+	if c.Closed() {
+		println("test1: Closed before Recv zero:", c.Impl());
+	}
+
+	for i := 0; i < 3; i++ {
+		// recv a close signal (a zero value)
+		if x := c.Recv(); x != 0 {
+			println("test1: recv on closed got non-zero:", x, c.Impl());
+		}
+
+		// should now be closed.
+		if !c.Closed() {
+			println("test1: not closed after recv zero", c.Impl());
+		}
+
+		// should work with ,ok: received a value without blocking, so ok == true.
+		x, ok := c.Nbrecv();
+		if !ok {
+			println("test1: recv on closed got not ok", c.Impl());
+		}
+		if x != 0 {
+			println("test1: recv ,ok on closed got non-zero:", x, c.Impl());
+		}
+	}
+
+	// send should work with ,ok too: sent a value without blocking, so ok == true.
+	ok := c.Nbsend(1);
+	if !ok {
+		println("test1: send on closed got not ok", c.Impl());
+	}
+
+	// but the value should have been discarded.
+	if x := c.Recv(); x != 0 {
+		println("test1: recv on closed got non-zero after send on closed:", x, c.Impl());
+	}
+
+	// similarly Send.
+	c.Send(2);
+	if x := c.Recv(); x != 0 {
+		println("test1: recv on closed got non-zero after send on closed:", x, c.Impl());
+	}
+}
+
+func testasync1(c Chan) {
+	// not closed until the close signal (a zero value) has been received.
+	if c.Closed() {
+		println("testasync1: Closed before Recv zero:", c.Impl());
+	}
+
+	// should be able to get the last value via Recv
+	if x := c.Recv(); x != 1 {
+		println("testasync1: Recv did not get 1:", x, c.Impl());
+	}
+
+	test1(c);
+}
+
+func testasync2(c Chan) {
+	// not closed until the close signal (a zero value) has been received.
+	if c.Closed() {
+		println("testasync2: Closed before Recv zero:", c.Impl());
+	}
+
+	// should be able to get the last value via Nbrecv
+	if x, ok := c.Nbrecv(); !ok || x != 1 {
+		println("testasync2: Nbrecv did not get 1, true:", x, ok, c.Impl());
+	}
+
+	test1(c);
+}
+
+func closedsync() chan int {
+	c := make(chan int);
+	close(c);
+	return c;
+}
+
+func closedasync() chan int {
+	c := make(chan int, 2);
+	c <- 1;
+	close(c);
+	return c;
+}
+
+func main() {
+	test1(XChan(closedsync()));
+	test1(SChan(closedsync()));
+
+	testasync1(XChan(closedasync()));
+	testasync1(SChan(closedasync()));
+	testasync2(XChan(closedasync()));
+	testasync2(SChan(closedasync()));
+}