gn: beginnings of format command

tools/gn/parser_unittest.cc

Index: tools/gn/parser_unittest.cc
diff --git a/tools/gn/parser_unittest.cc b/tools/gn/parser_unittest.cc
index 1205038a8bccf7cf92b1c04c598ac5425cb48014..09930a461d6c64f5917d9c2ddca5c9690fec164a 100644
--- a/tools/gn/parser_unittest.cc
+++ b/tools/gn/parser_unittest.cc
@@ -491,6 +491,51 @@ TEST(Parser, LongExpression) {
   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);
 }