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-rw-r--r--test/chancap.go71
1 files changed, 71 insertions, 0 deletions
diff --git a/test/chancap.go b/test/chancap.go
new file mode 100644
index 0000000..8dce924
--- /dev/null
+++ b/test/chancap.go
@@ -0,0 +1,71 @@
+// run
+
+// 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 the cap predeclared function applied to channels.
+
+package main
+
+import (
+ "strings"
+ "unsafe"
+)
+
+type T chan int
+
+const ptrSize = unsafe.Sizeof((*byte)(nil))
+
+func main() {
+ c := make(T, 10)
+ if len(c) != 0 || cap(c) != 10 {
+ println("chan len/cap ", len(c), cap(c), " want 0 10")
+ panic("fail")
+ }
+
+ for i := 0; i < 3; i++ {
+ c <- i
+ }
+ if len(c) != 3 || cap(c) != 10 {
+ println("chan len/cap ", len(c), cap(c), " want 3 10")
+ panic("fail")
+ }
+
+ c = make(T)
+ if len(c) != 0 || cap(c) != 0 {
+ println("chan len/cap ", len(c), cap(c), " want 0 0")
+ panic("fail")
+ }
+
+ n := -1
+ shouldPanic("makechan: size out of range", func() { _ = make(T, n) })
+ shouldPanic("makechan: size out of range", func() { _ = make(T, int64(n)) })
+ if ptrSize == 8 {
+ // Test mem > maxAlloc
+ var n2 int64 = 1 << 59
+ shouldPanic("makechan: size out of range", func() { _ = make(T, int(n2)) })
+ // Test elem.size*cap overflow
+ n2 = 1<<63 - 1
+ shouldPanic("makechan: size out of range", func() { _ = make(T, int(n2)) })
+ } else {
+ n = 1<<31 - 1
+ shouldPanic("makechan: size out of range", func() { _ = make(T, n) })
+ shouldPanic("makechan: size out of range", func() { _ = make(T, int64(n)) })
+ }
+}
+
+func shouldPanic(str string, f func()) {
+ defer func() {
+ err := recover()
+ if err == nil {
+ panic("did not panic")
+ }
+ s := err.(error).Error()
+ if !strings.Contains(s, str) {
+ panic("got panic " + s + ", want " + str)
+ }
+ }()
+
+ f()
+}