gn: beginnings of format command

tools/gn/parser_unittest.cc

 // Copyright (c) 2013 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.
 
 #include <iostream>
 #include <sstream>
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "tools/gn/input_file.h"
 #include "tools/gn/parser.h"
@@ skipping 473 matching lines @@
     "  BINARY(||)\n"
     "   BINARY(&&)\n"
     "    BINARY(+)\n"
     "     IDENTIFIER(b)\n"
     "     IDENTIFIER(c)\n"
     "    IDENTIFIER(d)\n"
     "   IDENTIFIER(e)\n";
   DoParserPrintTest(input, expected);
 }
 
+TEST(Parser, CommentsStandalone) {
+  const char* input = "# Toplevel comment.\n\nexecutable(\"wee\") {}\n";
+  const char* expected =
+    "BLOCK\n"
+    " +BEFORE_COMMENT(\"# Toplevel comment.\")\n"
+    " FUNCTION(executable)\n"
+    "  LIST\n"
+    "   LITERAL(\"wee\")\n"
+    "  BLOCK\n";
+  DoParserPrintTest(input, expected);
+}
+
+TEST(Parser, CommentsStandaloneEof) {
+  const char* input = "executable(\"wee\") {}\n# EOF comment.\n";
+  const char* expected =
+    "BLOCK\n"
+    " +AFTER_COMMENT(\"# EOF comment.\")\n"
+    " FUNCTION(executable)\n"
+    "  LIST\n"
+    "   LITERAL(\"wee\")\n"
+    "  BLOCK\n";
+  DoParserPrintTest(input, expected);
+}
+
+/* TODO(scottmg): Not implemented yet.
+TEST(Parser, CommentsSuffix) {
+  const char* input = "executable(\"wee\") { # This is some stuff.\n"
+    "sources = [ \"a.cc\"\n"
+    "] }";
+  const char* expected =
+    "BLOCK\n"
+    " FUNCTION(executable)\n"
+    "  LIST\n"
+    "   LITERAL(\"wee\")\n"
+    "    +SUFFIX_COMMENT(\"# This is some stuff.\")\n"
+    "  BLOCK\n"
+    "   BINARY(=)\n"
+    "    IDENTIFIER(sources)\n"
+    "    LIST\n"
+    "     LITERAL(\"a.cc\")\n"
+    "      +SUFFIX_COMMENT(\"# And another comment here.\")\n";
+  DoParserPrintTest(input, expected);
+}
+*/
+
 TEST(Parser, HangingIf) {
   DoParserErrorTest("if", 1, 1);
 }
 
 TEST(Parser, NegatingList) {
   DoParserErrorTest("executable(\"wee\") { sources =- [ \"foo.cc\" ] }", 1, 30);
 }