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crypto/internal/hash_test.go

@@ -0,0 +1,62 @@
+//
+// Copyright Coinbase, Inc. All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package internal
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestByteSub(t *testing.T) {
+	f := bytes.Repeat([]byte{0xFF}, 32)
+	ByteSub(f)
+	require.Equal(t, f[0], byte(0xFE))
+	for i := 1; i < len(f); i++ {
+		require.Equal(t, f[i], byte(0xFF))
+	}
+	ByteSub(f)
+	require.Equal(t, f[0], byte(0xFD))
+	for i := 1; i < len(f); i++ {
+		require.Equal(t, f[i], byte(0xFF))
+	}
+	f[0] = 0x2
+	ByteSub(f)
+	for i := 1; i < len(f); i++ {
+		require.Equal(t, f[i], byte(0xFF))
+	}
+	ByteSub(f)
+	require.Equal(t, f[0], byte(0xFF))
+	require.Equal(t, f[1], byte(0xFE))
+	for i := 2; i < len(f); i++ {
+		require.Equal(t, f[i], byte(0xFF))
+	}
+	ByteSub(f)
+	require.Equal(t, f[0], byte(0xFE))
+	require.Equal(t, f[1], byte(0xFE))
+	for i := 2; i < len(f); i++ {
+		require.Equal(t, f[i], byte(0xFF))
+	}
+	f[0] = 1
+	f[1] = 1
+	ByteSub(f)
+	require.Equal(t, f[0], byte(0xFF))
+	require.Equal(t, f[1], byte(0xFF))
+	require.Equal(t, f[2], byte(0xFE))
+	for i := 3; i < len(f); i++ {
+		require.Equal(t, f[i], byte(0xFF))
+	}
+}
+
+func TestByteSubAll1(t *testing.T) {
+	f := bytes.Repeat([]byte{0x1}, 32)
+	ByteSub(f)
+	for i := 0; i < len(f); i++ {
+		require.Equal(t, f[i], byte(0xFF))
+	}
+}