1 files changed, 47 insertions, 0 deletions
diff --git a/libgo/go/go/types/token_test.go b/libgo/go/go/types/token_test.go
new file mode 100644
index 00000000000..705bb295a16
--- /dev/null
+++ b/libgo/go/go/types/token_test.go
@@ -0,0 +1,47 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file checks invariants of token.Token ordering that we rely on
+// since package go/token doesn't provide any guarantees at the moment.
+
+package types
+
+import (
+	"go/token"
+	"testing"
+)
+
+var assignOps = map[token.Token]token.Token{
+	token.ADD_ASSIGN:     token.ADD,
+	token.SUB_ASSIGN:     token.SUB,
+	token.MUL_ASSIGN:     token.MUL,
+	token.QUO_ASSIGN:     token.QUO,
+	token.REM_ASSIGN:     token.REM,
+	token.AND_ASSIGN:     token.AND,
+	token.OR_ASSIGN:      token.OR,
+	token.XOR_ASSIGN:     token.XOR,
+	token.SHL_ASSIGN:     token.SHL,
+	token.SHR_ASSIGN:     token.SHR,
+	token.AND_NOT_ASSIGN: token.AND_NOT,
+}
+
+func TestZeroTok(t *testing.T) {
+	// zero value for token.Token must be token.ILLEGAL
+	var zero token.Token
+	if token.ILLEGAL != zero {
+		t.Errorf("%s == %d; want 0", token.ILLEGAL, zero)
+	}
+}
+
+func TestAssignOp(t *testing.T) {
+	// there are fewer than 256 tokens
+	for i := 0; i < 256; i++ {
+		tok := token.Token(i)
+		got := assignOp(tok)
+		want := assignOps[tok]
+		if got != want {
+			t.Errorf("for assignOp(%s): got %s; want %s", tok, got, want)
+		}
+	}
+}