diff --git a/src/runtime/chan_test.go b/src/runtime/chan_test.go
index 66dfd6f8d87..0b918bb99f6 100644
--- a/src/runtime/chan_test.go
+++ b/src/runtime/chan_test.go
@@ -218,6 +218,81 @@ func TestNonblockRecvRace(t *testing.T) {
 	}
 }
 
+// This test checks that select acts on the state of the channels at one
+// moment in the execution, not over a smeared time window.
+// In the test, one goroutine does:
+//	create c1, c2
+//	make c1 ready for receiving
+//	create second goroutine
+//	make c2 ready for receiving
+//	make c1 no longer ready for receiving (if possible)
+// The second goroutine does a non-blocking select receiving from c1 and c2.
+// From the time the second goroutine is created, at least one of c1 and c2
+// is always ready for receiving, so the select in the second goroutine must
+// always receive from one or the other. It must never execute the default case.
+func TestNonblockSelectRace(t *testing.T) {
+	n := 100000
+	if testing.Short() {
+		n = 1000
+	}
+	done := make(chan bool, 1)
+	for i := 0; i < n; i++ {
+		c1 := make(chan int, 1)
+		c2 := make(chan int, 1)
+		c1 <- 1
+		go func() {
+			select {
+			case <-c1:
+			case <-c2:
+			default:
+				done <- false
+				return
+			}
+			done <- true
+		}()
+		c2 <- 1
+		select {
+		case <-c1:
+		default:
+		}
+		if !<-done {
+			t.Fatal("no chan is ready")
+		}
+	}
+}
+
+// Same as TestNonblockSelectRace, but close(c2) replaces c2 <- 1.
+func TestNonblockSelectRace2(t *testing.T) {
+	n := 100000
+	if testing.Short() {
+		n = 1000
+	}
+	done := make(chan bool, 1)
+	for i := 0; i < n; i++ {
+		c1 := make(chan int, 1)
+		c2 := make(chan int)
+		c1 <- 1
+		go func() {
+			select {
+			case <-c1:
+			case <-c2:
+			default:
+				done <- false
+				return
+			}
+			done <- true
+		}()
+		close(c2)
+		select {
+		case <-c1:
+		default:
+		}
+		if !<-done {
+			t.Fatal("no chan is ready")
+		}
+	}
+}
+
 func TestSelfSelect(t *testing.T) {
 	// Ensure that send/recv on the same chan in select
 	// does not crash nor deadlock.