diff --git a/ws/message_test.go b/ws/message_test.go
index 2ecc989..04254c4 100644
--- a/ws/message_test.go
+++ b/ws/message_test.go
@@ -139,6 +139,22 @@ func TestReadEOF(t *testing.T) {
 			"complete extended 64 bits length",
 			[]byte{0x82,127, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
 			false, true,
+		}, {
+			"missing mask",
+			[]byte{0x82,0x80},
+			true, false,
+		}, {
+			"incomplete mask 1",
+			[]byte{0x82,0x80, 0x00},
+			true, false,
+		}, {
+			"incomplete mask 2",
+			[]byte{0x82,0x80, 0x00, 0x00, 0x00},
+			true, false,
+		},{
+			"complete mask",
+			[]byte{0x82,0x80, 0x00, 0x00, 0x00, 0x00},
+			false, false,
 		},
 	}