adjust test sleep timing to avoid spurious failure

- refactor ConsumeWithSpeed
 - documentation

Signed-off-by: Morgan Bauer <mbauer@us.ibm.com>

pkg/integration/utils.go

@@ -272,15 +272,12 @@ func RandomTmpDirPath(s string, platform string) string {
 	return filepath.ToSlash(path) // Using /
 }
 
-// ConsumeWithSpeed reads chunkSize bytes from reader after every interval.
-// Returns total read bytes.
+// ConsumeWithSpeed reads chunkSize bytes from reader before sleeping
+// for interval duration. Returns total read bytes. Send true to the
+// stop channel to return before reading to EOF on the reader.
 func ConsumeWithSpeed(reader io.Reader, chunkSize int, interval time.Duration, stop chan bool) (n int, err error) {
 	buffer := make([]byte, chunkSize)
 	for {
-		select {
-		case <-stop:
-			return
-		default:
 		var readBytes int
 		readBytes, err = reader.Read(buffer)
 		n += readBytes
@@ -290,7 +287,10 @@ func ConsumeWithSpeed(reader io.Reader, chunkSize int, interval time.Duration, s
 			}
 			return
 		}
-			time.Sleep(interval)
+		select {
+		case <-stop:
+			return
+		case <-time.After(interval):
 		}
 	}
 }

pkg/integration/utils_test.go

@@ -363,7 +363,7 @@ func TestConsumeWithSpeed(t *testing.T) {
 	reader := strings.NewReader("1234567890")
 	chunksize := 2
 
-	bytes1, err := ConsumeWithSpeed(reader, chunksize, 1*time.Millisecond, nil)
+	bytes1, err := ConsumeWithSpeed(reader, chunksize, 1*time.Second, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -385,7 +385,7 @@ func TestConsumeWithSpeedWithStop(t *testing.T) {
 		stopIt <- true
 	}()
 
-	bytes1, err := ConsumeWithSpeed(reader, chunksize, 2*time.Millisecond, stopIt)
+	bytes1, err := ConsumeWithSpeed(reader, chunksize, 20*time.Millisecond, stopIt)
 	if err != nil {
 		t.Fatal(err)
 	}