diff --git a/amt_test.go b/amt_test.go
index 837ae11..85067f8 100644
--- a/amt_test.go
+++ b/amt_test.go
@@ -1092,13 +1092,13 @@ func TestForEachParallelTracked(t *testing.T) {
 				}
 			}
 			m.Lock()
+			defer m.Unlock()
 			_, ok := expectedTrails[trailStr]
 			if !ok {
 				return fmt.Errorf("unexpected trail: %s", trailStr)
 			}
 			delete(expectedTrails, trailStr)
 			delete(foundVals, i)
-			m.Unlock()
 			return nil
 		})
 		if err != nil {
@@ -1144,13 +1144,13 @@ func TestForEachParallelTracked(t *testing.T) {
 				}
 			}
 			m.Lock()
+			defer m.Unlock()
 			_, ok := expectedTrails[trailStr]
 			if !ok {
 				return fmt.Errorf("unexpected trail: %s", trailStr)
 			}
 			delete(expectedTrails, trailStr)
 			delete(foundVals, i)
-			m.Unlock()
 			return nil
 		})
 		if err != nil {
@@ -1196,13 +1196,13 @@ func TestForEachParallelTracked(t *testing.T) {
 				}
 			}
 			m.Lock()
+			defer m.Unlock()
 			_, ok := expectedTrails[trailStr]
 			if !ok {
 				return fmt.Errorf("unexpected trail: %s", trailStr)
 			}
 			delete(expectedTrails, trailStr)
 			delete(foundVals, i)
-			m.Unlock()
 			return nil
 		})
 		if err != nil {
@@ -1272,13 +1272,13 @@ func TestForEachParallelTrackedWithNodeSink(t *testing.T) {
 				}
 			}
 			m.Lock()
+			defer m.Unlock()
 			_, ok := expectedTrails[trailStr]
 			if !ok {
 				return fmt.Errorf("unexpected trail: %s", trailStr)
 			}
 			delete(expectedTrails, trailStr)
 			delete(foundVals, i)
-			m.Unlock()
 			return nil
 		})
 		if err != nil {
@@ -1332,13 +1332,13 @@ func TestForEachParallelTrackedWithNodeSink(t *testing.T) {
 				}
 			}
 			m.Lock()
+			defer m.Unlock()
 			_, ok := expectedTrails[trailStr]
 			if !ok {
 				return fmt.Errorf("unexpected trail: %s", trailStr)
 			}
 			delete(expectedTrails, trailStr)
 			delete(foundVals, i)
-			m.Unlock()
 			return nil
 		})
 		if err != nil {
@@ -1389,13 +1389,13 @@ func TestForEachParallelTrackedWithNodeSink(t *testing.T) {
 				}
 			}
 			m.Lock()
+			defer m.Unlock()
 			_, ok := expectedTrails[trailStr]
 			if !ok {
 				return fmt.Errorf("unexpected trail: %s", trailStr)
 			}
 			delete(expectedTrails, trailStr)
 			delete(foundVals, i)
-			m.Unlock()
 			return nil
 		})
 		if err != nil {