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()
+}