fixes broken random value generation

Author: apoorvajagtap

prepared_test.go

@@ -33,6 +33,11 @@ var preparedMessageTests = []struct {
 }
 
 func TestPreparedMessage(t *testing.T) {
+	testRand := rand.New(rand.NewSource(99))
+	prevMaskRand := maskRand
+	maskRand = testRand
+	defer func() { maskRand = prevMaskRand }()
+
 	for _, tt := range preparedMessageTests {
 		var data = []byte("this is a test")
 		var buf bytes.Buffer
@@ -43,7 +48,7 @@ func TestPreparedMessage(t *testing.T) {
 		c.SetCompressionLevel(tt.compressionLevel)
 
 		// Seed random number generator for consistent frame mask.
-		rand.Seed(1234)
+		testRand.Seed(1234)
 
 		if err := c.WriteMessage(tt.messageType, data); err != nil {
 			t.Fatal(err)
@@ -59,7 +64,7 @@ func TestPreparedMessage(t *testing.T) {
 		copy(data, "hello world")
 
 		// Seed random number generator for consistent frame mask.
-		rand.Seed(1234)
+		testRand.Seed(1234)
 
 		buf.Reset()
 		if err := c.WritePreparedMessage(pm); err != nil {