Rename test.py to val.py (#4000)

utils/augmentations.py

@@ -90,7 +90,7 @@ def letterbox(im, new_shape=(640, 640), color=(114, 114, 114), auto=True, scaleF
 
     # Scale ratio (new / old)
     r = min(new_shape[0] / shape[0], new_shape[1] / shape[1])
-    if not scaleup:  # only scale down, do not scale up (for better test mAP)
+    if not scaleup:  # only scale down, do not scale up (for better val mAP)
         r = min(r, 1.0)
 
     # Compute padding