feture: showcasing select statement

concurrency/goroutines_test.go

@@ -2,6 +2,7 @@ package goroutines
 
 import (
 	"testing"
+	"time"
 )
 
 func TestAdd(t *testing.T) {
@@ -24,3 +25,33 @@ func TestChannelSynchronization(t *testing.T) {
 	<-done // this is blocked until something is pushed into.
 
 }
+
+// Showecase of the very nice Select feature
+func TestSelectWithTimeout(t *testing.T) {
+
+	ch1 := make(chan int)
+	ch2 := make(chan int)
+
+	// Start two goroutines with fixed delays
+	go func() {
+		time.Sleep(300 * time.Millisecond)
+		ch1 <- 10
+	}()
+	go func() {
+		time.Sleep(700 * time.Millisecond)
+		ch2 <- 20
+	}()
+
+	select { //accepts what comes firts.useful for tasks like multiplexing, timeouts
+
+	case result := <-ch1:
+		expected := 10
+		if result != expected {
+			t.Errorf("Expected %d from ch1, but got %d", expected, result)
+		}
+	case result := <-ch2:
+		t.Errorf("Did not expect to receive from ch2, but got %d", result)
+	case <-time.After(500 * time.Millisecond):
+		t.Error("Timeout occurred, but ch1 should have sent a value first")
+	}
+}