Fix some issues with whitespace in formatter.

mojom/mojom_parser/formatter/printer_test.go

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package formatter
 
 import (
         "mojom/mojom_parser/lexer"
         "mojom/mojom_parser/mojom"
         "testing"
@@ skipping 122 matching lines @@
 
         expected := `import "foo3.mojom";
 import "foo4.mojom";
 
 import "foo1.mojom";
 import "foo2.mojom";
 `
         checkEq(t, expected, p.result())
 }
 
+func TestWriteSingleLineComment(t *testing.T) {
+        commentText := "// Hello world."
+        token := lexer.Token{Kind: lexer.SingleLineComment, Text: commentText}
+        p := getNewPrinter()
+        p.writeSingleLineComment(token)
+        checkEq(t, commentText, p.result())
+}
+
+func TestWriteSingleLineCommentAddSpace(t *testing.T) {
+        commentText := "//Hello world."
+        token := lexer.Token{Kind: lexer.SingleLineComment, Text: commentText}
+        p := getNewPrinter()
+        p.writeSingleLineComment(token)
+        checkEq(t, "// Hello world.", p.result())
+}
+
 func TestWriteMultilineComments(t *testing.T) {
         commentText := `/*
  * Some comment.
  * More comments.
  * Even more comments.
 
  * And after a space.
  */`
         token := lexer.Token{Kind: lexer.MultiLineComment, Text: commentText}
         p := getNewPrinter()
@@ skipping 261 matching lines @@
         responseParams.InitAsScope(mojom.NewTestFileScope("test.scope"))
         responseParams.AddField(mojom.NewStructField(mojom.DeclTestData("rparam1"), mojom.SimpleTypeInt32, nil))
         responseParams.AddField(mojom.NewStructField(mojom.DeclTestData("rparam2"), mojom.SimpleTypeInt64, nil))
 
         mojomMethod := mojom.NewMojomMethod(mojom.DeclTestData("method_foo"), params, responseParams)
 
         p := getNewPrinter()
         p.writeDeclaredObject(mojomMethod)
         checkEq(t, "method_foo(int8 param1, int16 param2) => (int32 rparam1, int64 rparam2);", p.result())
 }