// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

library engine.scanner_test;

import 'package:analyzer/src/generated/error.dart';
import 'package:analyzer/src/generated/scanner.dart';
import 'package:analyzer/src/generated/source.dart';
import 'package:unittest/unittest.dart';

import '../reflective_tests.dart';
import '../utils.dart';
import 'test_support.dart';

main() {
  initializeTestEnvironment();
  runReflectiveTests(CharSequenceReaderTest);
  runReflectiveTests(KeywordStateTest);
  runReflectiveTests(ScannerTest);
  runReflectiveTests(TokenTypeTest);
}

class CharacterRangeReaderTest extends EngineTestCase {
  void test_advance() {
    CharSequenceReader baseReader = new CharSequenceReader("xyzzy");
    CharacterRangeReader reader = new CharacterRangeReader(baseReader, 1, 4);
    expect(reader.advance(), 0x79);
    expect(reader.advance(), 0x80);
    expect(reader.advance(), 0x80);
    expect(reader.advance(), -1);
    expect(reader.advance(), -1);
  }

  void test_creation() {
    CharSequenceReader baseReader = new CharSequenceReader("xyzzy");
    CharacterRangeReader reader = new CharacterRangeReader(baseReader, 1, 4);
    expect(reader, isNotNull);
  }

  void test_getOffset() {
    CharSequenceReader baseReader = new CharSequenceReader("xyzzy");
    CharacterRangeReader reader = new CharacterRangeReader(baseReader, 1, 2);
    expect(reader.offset, 1);
    reader.advance();
    expect(reader.offset, 2);
    reader.advance();
    expect(reader.offset, 2);
  }

  void test_getString() {
    CharSequenceReader baseReader = new CharSequenceReader("__xyzzy__");
    CharacterRangeReader reader = new CharacterRangeReader(baseReader, 2, 7);
    reader.offset = 5;
    expect(reader.getString(3, 0), "yzz");
    expect(reader.getString(4, 1), "zzy");
  }

  void test_peek() {
    CharSequenceReader baseReader = new CharSequenceReader("xyzzy");
    CharacterRangeReader reader = new CharacterRangeReader(baseReader, 1, 3);
    expect(reader.peek(), 0x79);
    expect(reader.peek(), 0x79);
    reader.advance();
    expect(reader.peek(), 0x80);
    expect(reader.peek(), 0x80);
    reader.advance();
    expect(reader.peek(), -1);
    expect(reader.peek(), -1);
  }

  void test_setOffset() {
    CharSequenceReader baseReader = new CharSequenceReader("xyzzy");
    CharacterRangeReader reader = new CharacterRangeReader(baseReader, 1, 4);
    reader.offset = 2;
    expect(reader.offset, 2);
  }
}

@reflectiveTest
class CharSequenceReaderTest {
  void test_advance() {
    CharSequenceReader reader = new CharSequenceReader("x");
    expect(reader.advance(), 0x78);
    expect(reader.advance(), -1);
    expect(reader.advance(), -1);
  }

  void test_creation() {
    expect(new CharSequenceReader("x"), isNotNull);
  }

  void test_getOffset() {
    CharSequenceReader reader = new CharSequenceReader("x");
    expect(reader.offset, -1);
    reader.advance();
    expect(reader.offset, 0);
    reader.advance();
    expect(reader.offset, 0);
  }

  void test_getString() {
    CharSequenceReader reader = new CharSequenceReader("xyzzy");
    reader.offset = 3;
    expect(reader.getString(1, 0), "yzz");
    expect(reader.getString(2, 1), "zzy");
  }

  void test_peek() {
    CharSequenceReader reader = new CharSequenceReader("xy");
    expect(reader.peek(), 0x78);
    expect(reader.peek(), 0x78);
    reader.advance();
    expect(reader.peek(), 0x79);
    expect(reader.peek(), 0x79);
    reader.advance();
    expect(reader.peek(), -1);
    expect(reader.peek(), -1);
  }

  void test_setOffset() {
    CharSequenceReader reader = new CharSequenceReader("xyz");
    reader.offset = 2;
    expect(reader.offset, 2);
  }
}

@reflectiveTest
class KeywordStateTest {
  void test_KeywordState() {
    //
    // Generate the test data to be scanned.
    //
    List<Keyword> keywords = Keyword.values;
    int keywordCount = keywords.length;
    List<String> textToTest = new List<String>(keywordCount * 3);
    for (int i = 0; i < keywordCount; i++) {
      String syntax = keywords[i].syntax;
      textToTest[i] = syntax;
      textToTest[i + keywordCount] = "${syntax}x";
      textToTest[i + keywordCount * 2] = syntax.substring(0, syntax.length - 1);
    }
    //
    // Scan each of the identifiers.
    //
    KeywordState firstState = KeywordState.KEYWORD_STATE;
    for (int i = 0; i < textToTest.length; i++) {
      String text = textToTest[i];
      int index = 0;
      int length = text.length;
      KeywordState state = firstState;
      while (index < length && state != null) {
        state = state.next(text.codeUnitAt(index));
        index++;
      }
      if (i < keywordCount) {
        // keyword
        expect(state, isNotNull);
        expect(state.keyword(), isNotNull);
        expect(state.keyword(), keywords[i]);
      } else if (i < keywordCount * 2) {
        // keyword + "x"
        expect(state, isNull);
      } else {
        // keyword.substring(0, keyword.length() - 1)
        expect(state, isNotNull);
      }
    }
  }
}

@reflectiveTest
class ScannerTest {
  void fail_incomplete_string_interpolation() {
    // https://code.google.com/p/dart/issues/detail?id=18073
    _assertErrorAndTokens(
        ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 9, "\"foo \${bar", [
      new StringToken(TokenType.STRING, "\"foo ", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_EXPRESSION, "\${", 5),
      new StringToken(TokenType.IDENTIFIER, "bar", 7)
    ]);
  }

  void test_ampersand() {
    _assertToken(TokenType.AMPERSAND, "&");
  }

  void test_ampersand_ampersand() {
    _assertToken(TokenType.AMPERSAND_AMPERSAND, "&&");
  }

  void test_ampersand_eq() {
    _assertToken(TokenType.AMPERSAND_EQ, "&=");
  }

  void test_at() {
    _assertToken(TokenType.AT, "@");
  }

  void test_backping() {
    _assertToken(TokenType.BACKPING, "`");
  }

  void test_backslash() {
    _assertToken(TokenType.BACKSLASH, "\\");
  }

  void test_bang() {
    _assertToken(TokenType.BANG, "!");
  }

  void test_bang_eq() {
    _assertToken(TokenType.BANG_EQ, "!=");
  }

  void test_bar() {
    _assertToken(TokenType.BAR, "|");
  }

  void test_bar_bar() {
    _assertToken(TokenType.BAR_BAR, "||");
  }

  void test_bar_eq() {
    _assertToken(TokenType.BAR_EQ, "|=");
  }

  void test_caret() {
    _assertToken(TokenType.CARET, "^");
  }

  void test_caret_eq() {
    _assertToken(TokenType.CARET_EQ, "^=");
  }

  void test_close_curly_bracket() {
    _assertToken(TokenType.CLOSE_CURLY_BRACKET, "}");
  }

  void test_close_paren() {
    _assertToken(TokenType.CLOSE_PAREN, ")");
  }

  void test_close_quare_bracket() {
    _assertToken(TokenType.CLOSE_SQUARE_BRACKET, "]");
  }

  void test_colon() {
    _assertToken(TokenType.COLON, ":");
  }

  void test_comma() {
    _assertToken(TokenType.COMMA, ",");
  }

  void test_comment_disabled_multi() {
    Scanner scanner = new Scanner(
        null,
        new CharSequenceReader("/* comment */ "),
        AnalysisErrorListener.NULL_LISTENER);
    scanner.preserveComments = false;
    Token token = scanner.tokenize();
    expect(token, isNotNull);
    expect(token.precedingComments, isNull);
  }

  void test_comment_generic_method_type_assign() {
    _assertComment(TokenType.MULTI_LINE_COMMENT, "/*=comment*/");
    _assertComment(TokenType.GENERIC_METHOD_TYPE_ASSIGN, "/*=comment*/",
        genericMethodComments: true);
  }

  void test_comment_generic_method_type_list() {
    _assertComment(TokenType.MULTI_LINE_COMMENT, "/*<comment>*/");
    _assertComment(TokenType.GENERIC_METHOD_TYPE_LIST, "/*<comment>*/",
        genericMethodComments: true);
  }

  void test_comment_multi() {
    _assertComment(TokenType.MULTI_LINE_COMMENT, "/* comment */");
  }

  void test_comment_multi_lineEnds() {
    String code = r'''
/**
 * aa
 * bbb
 * c
 */''';
    GatheringErrorListener listener = new GatheringErrorListener();
    Scanner scanner = new Scanner(null, new CharSequenceReader(code), listener);
    scanner.tokenize();
    expect(
        scanner.lineStarts,
        equals(<int>[
          code.indexOf('/**'),
          code.indexOf(' * aa'),
          code.indexOf(' * bbb'),
          code.indexOf(' * c'),
          code.indexOf(' */')
        ]));
  }

  void test_comment_multi_unterminated() {
    _assertError(ScannerErrorCode.UNTERMINATED_MULTI_LINE_COMMENT, 3, "/* x");
  }

  void test_comment_nested() {
    _assertComment(
        TokenType.MULTI_LINE_COMMENT, "/* comment /* within a */ comment */");
  }

  void test_comment_single() {
    _assertComment(TokenType.SINGLE_LINE_COMMENT, "// comment");
  }

  void test_double_both_E() {
    _assertToken(TokenType.DOUBLE, "0.123E4");
  }

  void test_double_both_e() {
    _assertToken(TokenType.DOUBLE, "0.123e4");
  }

  void test_double_fraction() {
    _assertToken(TokenType.DOUBLE, ".123");
  }

  void test_double_fraction_E() {
    _assertToken(TokenType.DOUBLE, ".123E4");
  }

  void test_double_fraction_e() {
    _assertToken(TokenType.DOUBLE, ".123e4");
  }

  void test_double_missingDigitInExponent() {
    _assertError(ScannerErrorCode.MISSING_DIGIT, 1, "1e");
  }

  void test_double_whole_E() {
    _assertToken(TokenType.DOUBLE, "12E4");
  }

  void test_double_whole_e() {
    _assertToken(TokenType.DOUBLE, "12e4");
  }

  void test_eq() {
    _assertToken(TokenType.EQ, "=");
  }

  void test_eq_eq() {
    _assertToken(TokenType.EQ_EQ, "==");
  }

  void test_gt() {
    _assertToken(TokenType.GT, ">");
  }

  void test_gt_eq() {
    _assertToken(TokenType.GT_EQ, ">=");
  }

  void test_gt_gt() {
    _assertToken(TokenType.GT_GT, ">>");
  }

  void test_gt_gt_eq() {
    _assertToken(TokenType.GT_GT_EQ, ">>=");
  }

  void test_hash() {
    _assertToken(TokenType.HASH, "#");
  }

  void test_hexidecimal() {
    _assertToken(TokenType.HEXADECIMAL, "0x1A2B3C");
  }

  void test_hexidecimal_missingDigit() {
    _assertError(ScannerErrorCode.MISSING_HEX_DIGIT, 1, "0x");
  }

  void test_identifier() {
    _assertToken(TokenType.IDENTIFIER, "result");
  }

  void test_illegalChar_cyrillicLetter_middle() {
    _assertError(ScannerErrorCode.ILLEGAL_CHARACTER, 5, "Shche\u0433lov");
  }

  void test_illegalChar_cyrillicLetter_start() {
    _assertError(ScannerErrorCode.ILLEGAL_CHARACTER, 0, "\u0429");
  }

  void test_illegalChar_nbsp() {
    _assertError(ScannerErrorCode.ILLEGAL_CHARACTER, 0, "\u00A0");
  }

  void test_illegalChar_notLetter() {
    _assertError(ScannerErrorCode.ILLEGAL_CHARACTER, 0, "\u0312");
  }

  void test_index() {
    _assertToken(TokenType.INDEX, "[]");
  }

  void test_index_eq() {
    _assertToken(TokenType.INDEX_EQ, "[]=");
  }

  void test_int() {
    _assertToken(TokenType.INT, "123");
  }

  void test_int_initialZero() {
    _assertToken(TokenType.INT, "0123");
  }

  void test_keyword_abstract() {
    _assertKeywordToken("abstract");
  }

  void test_keyword_as() {
    _assertKeywordToken("as");
  }

  void test_keyword_assert() {
    _assertKeywordToken("assert");
  }

  void test_keyword_break() {
    _assertKeywordToken("break");
  }

  void test_keyword_case() {
    _assertKeywordToken("case");
  }

  void test_keyword_catch() {
    _assertKeywordToken("catch");
  }

  void test_keyword_class() {
    _assertKeywordToken("class");
  }

  void test_keyword_const() {
    _assertKeywordToken("const");
  }

  void test_keyword_continue() {
    _assertKeywordToken("continue");
  }

  void test_keyword_default() {
    _assertKeywordToken("default");
  }

  void test_keyword_deferred() {
    _assertKeywordToken("deferred");
  }

  void test_keyword_do() {
    _assertKeywordToken("do");
  }

  void test_keyword_dynamic() {
    _assertKeywordToken("dynamic");
  }

  void test_keyword_else() {
    _assertKeywordToken("else");
  }

  void test_keyword_enum() {
    _assertKeywordToken("enum");
  }

  void test_keyword_export() {
    _assertKeywordToken("export");
  }

  void test_keyword_extends() {
    _assertKeywordToken("extends");
  }

  void test_keyword_factory() {
    _assertKeywordToken("factory");
  }

  void test_keyword_false() {
    _assertKeywordToken("false");
  }

  void test_keyword_final() {
    _assertKeywordToken("final");
  }

  void test_keyword_finally() {
    _assertKeywordToken("finally");
  }

  void test_keyword_for() {
    _assertKeywordToken("for");
  }

  void test_keyword_get() {
    _assertKeywordToken("get");
  }

  void test_keyword_if() {
    _assertKeywordToken("if");
  }

  void test_keyword_implements() {
    _assertKeywordToken("implements");
  }

  void test_keyword_import() {
    _assertKeywordToken("import");
  }

  void test_keyword_in() {
    _assertKeywordToken("in");
  }

  void test_keyword_is() {
    _assertKeywordToken("is");
  }

  void test_keyword_library() {
    _assertKeywordToken("library");
  }

  void test_keyword_new() {
    _assertKeywordToken("new");
  }

  void test_keyword_null() {
    _assertKeywordToken("null");
  }

  void test_keyword_operator() {
    _assertKeywordToken("operator");
  }

  void test_keyword_part() {
    _assertKeywordToken("part");
  }

  void test_keyword_rethrow() {
    _assertKeywordToken("rethrow");
  }

  void test_keyword_return() {
    _assertKeywordToken("return");
  }

  void test_keyword_set() {
    _assertKeywordToken("set");
  }

  void test_keyword_static() {
    _assertKeywordToken("static");
  }

  void test_keyword_super() {
    _assertKeywordToken("super");
  }

  void test_keyword_switch() {
    _assertKeywordToken("switch");
  }

  void test_keyword_this() {
    _assertKeywordToken("this");
  }

  void test_keyword_throw() {
    _assertKeywordToken("throw");
  }

  void test_keyword_true() {
    _assertKeywordToken("true");
  }

  void test_keyword_try() {
    _assertKeywordToken("try");
  }

  void test_keyword_typedef() {
    _assertKeywordToken("typedef");
  }

  void test_keyword_var() {
    _assertKeywordToken("var");
  }

  void test_keyword_void() {
    _assertKeywordToken("void");
  }

  void test_keyword_while() {
    _assertKeywordToken("while");
  }

  void test_keyword_with() {
    _assertKeywordToken("with");
  }

  void test_lineInfo_multilineComment() {
    String source = "/*\r *\r */";
    _assertLineInfo(source, [
      new ScannerTest_ExpectedLocation(0, 1, 1),
      new ScannerTest_ExpectedLocation(4, 2, 2),
      new ScannerTest_ExpectedLocation(source.length - 1, 3, 3)
    ]);
  }

  void test_lineInfo_multilineString() {
    String source = "'''a\r\nbc\r\nd'''";
    _assertLineInfo(source, [
      new ScannerTest_ExpectedLocation(0, 1, 1),
      new ScannerTest_ExpectedLocation(7, 2, 2),
      new ScannerTest_ExpectedLocation(source.length - 1, 3, 4)
    ]);
  }

  void test_lineInfo_multilineString_raw() {
    String source = "var a = r'''\nblah\n''';\n\nfoo";
    _assertLineInfo(source, [
      new ScannerTest_ExpectedLocation(0, 1, 1),
      new ScannerTest_ExpectedLocation(14, 2, 2),
      new ScannerTest_ExpectedLocation(source.length - 2, 5, 2)
    ]);
  }

  void test_lineInfo_simpleClass() {
    String source =
        "class Test {\r\n    String s = '...';\r\n    int get x => s.MISSING_GETTER;\r\n}";
    _assertLineInfo(source, [
      new ScannerTest_ExpectedLocation(0, 1, 1),
      new ScannerTest_ExpectedLocation(source.indexOf("MISSING_GETTER"), 3, 20),
      new ScannerTest_ExpectedLocation(source.length - 1, 4, 1)
    ]);
  }

  void test_lineInfo_slashN() {
    String source = "class Test {\n}";
    _assertLineInfo(source, [
      new ScannerTest_ExpectedLocation(0, 1, 1),
      new ScannerTest_ExpectedLocation(source.indexOf("}"), 2, 1)
    ]);
  }

  void test_lt() {
    _assertToken(TokenType.LT, "<");
  }

  void test_lt_eq() {
    _assertToken(TokenType.LT_EQ, "<=");
  }

  void test_lt_lt() {
    _assertToken(TokenType.LT_LT, "<<");
  }

  void test_lt_lt_eq() {
    _assertToken(TokenType.LT_LT_EQ, "<<=");
  }

  void test_minus() {
    _assertToken(TokenType.MINUS, "-");
  }

  void test_minus_eq() {
    _assertToken(TokenType.MINUS_EQ, "-=");
  }

  void test_minus_minus() {
    _assertToken(TokenType.MINUS_MINUS, "--");
  }

  void test_open_curly_bracket() {
    _assertToken(TokenType.OPEN_CURLY_BRACKET, "{");
  }

  void test_open_paren() {
    _assertToken(TokenType.OPEN_PAREN, "(");
  }

  void test_open_square_bracket() {
    _assertToken(TokenType.OPEN_SQUARE_BRACKET, "[");
  }

  void test_openSquareBracket() {
    _assertToken(TokenType.OPEN_SQUARE_BRACKET, "[");
  }

  void test_percent() {
    _assertToken(TokenType.PERCENT, "%");
  }

  void test_percent_eq() {
    _assertToken(TokenType.PERCENT_EQ, "%=");
  }

  void test_period() {
    _assertToken(TokenType.PERIOD, ".");
  }

  void test_period_period() {
    _assertToken(TokenType.PERIOD_PERIOD, "..");
  }

  void test_period_period_period() {
    _assertToken(TokenType.PERIOD_PERIOD_PERIOD, "...");
  }

  void test_periodAfterNumberNotIncluded_identifier() {
    _assertTokens("42.isEven()", [
      new StringToken(TokenType.INT, "42", 0),
      new Token(TokenType.PERIOD, 2),
      new StringToken(TokenType.IDENTIFIER, "isEven", 3),
      new Token(TokenType.OPEN_PAREN, 9),
      new Token(TokenType.CLOSE_PAREN, 10)
    ]);
  }

  void test_periodAfterNumberNotIncluded_period() {
    _assertTokens("42..isEven()", [
      new StringToken(TokenType.INT, "42", 0),
      new Token(TokenType.PERIOD_PERIOD, 2),
      new StringToken(TokenType.IDENTIFIER, "isEven", 4),
      new Token(TokenType.OPEN_PAREN, 10),
      new Token(TokenType.CLOSE_PAREN, 11)
    ]);
  }

  void test_plus() {
    _assertToken(TokenType.PLUS, "+");
  }

  void test_plus_eq() {
    _assertToken(TokenType.PLUS_EQ, "+=");
  }

  void test_plus_plus() {
    _assertToken(TokenType.PLUS_PLUS, "++");
  }

  void test_question() {
    _assertToken(TokenType.QUESTION, "?");
  }

  void test_question_dot() {
    _assertToken(TokenType.QUESTION_PERIOD, "?.");
  }

  void test_question_question() {
    _assertToken(TokenType.QUESTION_QUESTION, "??");
  }

  void test_question_question_eq() {
    _assertToken(TokenType.QUESTION_QUESTION_EQ, "??=");
  }

  void test_scriptTag_withArgs() {
    _assertToken(TokenType.SCRIPT_TAG, "#!/bin/dart -debug");
  }

  void test_scriptTag_withoutSpace() {
    _assertToken(TokenType.SCRIPT_TAG, "#!/bin/dart");
  }

  void test_scriptTag_withSpace() {
    _assertToken(TokenType.SCRIPT_TAG, "#! /bin/dart");
  }

  void test_semicolon() {
    _assertToken(TokenType.SEMICOLON, ";");
  }

  void test_setSourceStart() {
    int offsetDelta = 42;
    GatheringErrorListener listener = new GatheringErrorListener();
    Scanner scanner =
        new Scanner(null, new SubSequenceReader("a", offsetDelta), listener);
    scanner.setSourceStart(3, 9);
    scanner.tokenize();
    List<int> lineStarts = scanner.lineStarts;
    expect(lineStarts, isNotNull);
    expect(lineStarts.length, 3);
    expect(lineStarts[2], 33);
  }

  void test_slash() {
    _assertToken(TokenType.SLASH, "/");
  }

  void test_slash_eq() {
    _assertToken(TokenType.SLASH_EQ, "/=");
  }

  void test_star() {
    _assertToken(TokenType.STAR, "*");
  }

  void test_star_eq() {
    _assertToken(TokenType.STAR_EQ, "*=");
  }

  void test_startAndEnd() {
    Token token = _scan("a");
    Token previous = token.previous;
    expect(previous.next, token);
    expect(previous.previous, previous);
    Token next = token.next;
    expect(next.next, next);
    expect(next.previous, token);
  }

  void test_string_multi_double() {
    _assertToken(TokenType.STRING, "\"\"\"line1\nline2\"\"\"");
  }

  void test_string_multi_embeddedQuotes() {
    _assertToken(TokenType.STRING, "\"\"\"line1\n\"\"\nline2\"\"\"");
  }

  void test_string_multi_embeddedQuotes_escapedChar() {
    _assertToken(TokenType.STRING, "\"\"\"a\"\"\\tb\"\"\"");
  }

  void test_string_multi_interpolation_block() {
    _assertTokens("\"Hello \${name}!\"", [
      new StringToken(TokenType.STRING, "\"Hello ", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_EXPRESSION, "\${", 7),
      new StringToken(TokenType.IDENTIFIER, "name", 9),
      new Token(TokenType.CLOSE_CURLY_BRACKET, 13),
      new StringToken(TokenType.STRING, "!\"", 14)
    ]);
  }

  void test_string_multi_interpolation_identifier() {
    _assertTokens("\"Hello \$name!\"", [
      new StringToken(TokenType.STRING, "\"Hello ", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 7),
      new StringToken(TokenType.IDENTIFIER, "name", 8),
      new StringToken(TokenType.STRING, "!\"", 12)
    ]);
  }

  void test_string_multi_single() {
    _assertToken(TokenType.STRING, "'''string'''");
  }

  void test_string_multi_slashEnter() {
    _assertToken(TokenType.STRING, "'''\\\n'''");
  }

  void test_string_multi_unterminated() {
    _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 8,
        "'''string", [new StringToken(TokenType.STRING, "'''string", 0)]);
  }

  void test_string_multi_unterminated_interpolation_block() {
    _assertErrorAndTokens(
        ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 8, "'''\${name", [
      new StringToken(TokenType.STRING, "'''", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_EXPRESSION, "\${", 3),
      new StringToken(TokenType.IDENTIFIER, "name", 5),
      new StringToken(TokenType.STRING, "", 9)
    ]);
  }

  void test_string_multi_unterminated_interpolation_identifier() {
    _assertErrorAndTokens(
        ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 7, "'''\$name", [
      new StringToken(TokenType.STRING, "'''", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 3),
      new StringToken(TokenType.IDENTIFIER, "name", 4),
      new StringToken(TokenType.STRING, "", 8)
    ]);
  }

  void test_string_raw_multi_double() {
    _assertToken(TokenType.STRING, "r\"\"\"line1\nline2\"\"\"");
  }

  void test_string_raw_multi_single() {
    _assertToken(TokenType.STRING, "r'''string'''");
  }

  void test_string_raw_multi_unterminated() {
    String source = "r'''string";
    _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 9,
        source, [new StringToken(TokenType.STRING, source, 0)]);
  }

  void test_string_raw_simple_double() {
    _assertToken(TokenType.STRING, "r\"string\"");
  }

  void test_string_raw_simple_single() {
    _assertToken(TokenType.STRING, "r'string'");
  }

  void test_string_raw_simple_unterminated_eof() {
    String source = "r'string";
    _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 7,
        source, [new StringToken(TokenType.STRING, source, 0)]);
  }

  void test_string_raw_simple_unterminated_eol() {
    String source = "r'string";
    _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 8,
        "$source\n", [new StringToken(TokenType.STRING, source, 0)]);
  }

  void test_string_simple_double() {
    _assertToken(TokenType.STRING, "\"string\"");
  }

  void test_string_simple_escapedDollar() {
    _assertToken(TokenType.STRING, "'a\\\$b'");
  }

  void test_string_simple_interpolation_adjacentIdentifiers() {
    _assertTokens("'\$a\$b'", [
      new StringToken(TokenType.STRING, "'", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 1),
      new StringToken(TokenType.IDENTIFIER, "a", 2),
      new StringToken(TokenType.STRING, "", 3),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 3),
      new StringToken(TokenType.IDENTIFIER, "b", 4),
      new StringToken(TokenType.STRING, "'", 5)
    ]);
  }

  void test_string_simple_interpolation_block() {
    _assertTokens("'Hello \${name}!'", [
      new StringToken(TokenType.STRING, "'Hello ", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_EXPRESSION, "\${", 7),
      new StringToken(TokenType.IDENTIFIER, "name", 9),
      new Token(TokenType.CLOSE_CURLY_BRACKET, 13),
      new StringToken(TokenType.STRING, "!'", 14)
    ]);
  }

  void test_string_simple_interpolation_blockWithNestedMap() {
    _assertTokens("'a \${f({'b' : 'c'})} d'", [
      new StringToken(TokenType.STRING, "'a ", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_EXPRESSION, "\${", 3),
      new StringToken(TokenType.IDENTIFIER, "f", 5),
      new Token(TokenType.OPEN_PAREN, 6),
      new Token(TokenType.OPEN_CURLY_BRACKET, 7),
      new StringToken(TokenType.STRING, "'b'", 8),
      new Token(TokenType.COLON, 12),
      new StringToken(TokenType.STRING, "'c'", 14),
      new Token(TokenType.CLOSE_CURLY_BRACKET, 17),
      new Token(TokenType.CLOSE_PAREN, 18),
      new Token(TokenType.CLOSE_CURLY_BRACKET, 19),
      new StringToken(TokenType.STRING, " d'", 20)
    ]);
  }

  void test_string_simple_interpolation_firstAndLast() {
    _assertTokens("'\$greeting \$name'", [
      new StringToken(TokenType.STRING, "'", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 1),
      new StringToken(TokenType.IDENTIFIER, "greeting", 2),
      new StringToken(TokenType.STRING, " ", 10),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 11),
      new StringToken(TokenType.IDENTIFIER, "name", 12),
      new StringToken(TokenType.STRING, "'", 16)
    ]);
  }

  void test_string_simple_interpolation_identifier() {
    _assertTokens("'Hello \$name!'", [
      new StringToken(TokenType.STRING, "'Hello ", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 7),
      new StringToken(TokenType.IDENTIFIER, "name", 8),
      new StringToken(TokenType.STRING, "!'", 12)
    ]);
  }

  void test_string_simple_interpolation_missingIdentifier() {
    _assertTokens("'\$x\$'", [
      new StringToken(TokenType.STRING, "'", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 1),
      new StringToken(TokenType.IDENTIFIER, "x", 2),
      new StringToken(TokenType.STRING, "", 3),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 3),
      new StringToken(TokenType.STRING, "'", 4)
    ]);
  }

  void test_string_simple_interpolation_nonIdentifier() {
    _assertTokens("'\$1'", [
      new StringToken(TokenType.STRING, "'", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 1),
      new StringToken(TokenType.STRING, "1'", 2)
    ]);
  }

  void test_string_simple_single() {
    _assertToken(TokenType.STRING, "'string'");
  }

  void test_string_simple_unterminated_eof() {
    String source = "'string";
    _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 6,
        source, [new StringToken(TokenType.STRING, source, 0)]);
  }

  void test_string_simple_unterminated_eol() {
    String source = "'string";
    _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 7,
        "$source\r", [new StringToken(TokenType.STRING, source, 0)]);
  }

  void test_string_simple_unterminated_interpolation_block() {
    _assertErrorAndTokens(
        ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 6, "'\${name", [
      new StringToken(TokenType.STRING, "'", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_EXPRESSION, "\${", 1),
      new StringToken(TokenType.IDENTIFIER, "name", 3),
      new StringToken(TokenType.STRING, "", 7)
    ]);
  }

  void test_string_simple_unterminated_interpolation_identifier() {
    _assertErrorAndTokens(
        ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 5, "'\$name", [
      new StringToken(TokenType.STRING, "'", 0),
      new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 1),
      new StringToken(TokenType.IDENTIFIER, "name", 2),
      new StringToken(TokenType.STRING, "", 6)
    ]);
  }

  void test_tilde() {
    _assertToken(TokenType.TILDE, "~");
  }

  void test_tilde_slash() {
    _assertToken(TokenType.TILDE_SLASH, "~/");
  }

  void test_tilde_slash_eq() {
    _assertToken(TokenType.TILDE_SLASH_EQ, "~/=");
  }

  void test_unclosedPairInInterpolation() {
    GatheringErrorListener listener = new GatheringErrorListener();
    _scanWithListener("'\${(}'", listener);
  }

  void _assertComment(TokenType commentType, String source,
      {bool genericMethodComments: false}) {
    //
    // Test without a trailing end-of-line marker
    //
    Token token = _scan(source, genericMethodComments: genericMethodComments);
    expect(token, isNotNull);
    expect(token.type, TokenType.EOF);
    Token comment = token.precedingComments;
    expect(comment, isNotNull);
    expect(comment.type, commentType);
    expect(comment.offset, 0);
    expect(comment.length, source.length);
    expect(comment.lexeme, source);
    //
    // Test with a trailing end-of-line marker
    //
    token = _scan("$source\n", genericMethodComments: genericMethodComments);
    expect(token, isNotNull);
    expect(token.type, TokenType.EOF);
    comment = token.precedingComments;
    expect(comment, isNotNull);
    expect(comment.type, commentType);
    expect(comment.offset, 0);
    expect(comment.length, source.length);
    expect(comment.lexeme, source);
  }

  /**
   * Assert that scanning the given [source] produces an error with the given
   * code.
   *
   * [expectedError] the error that should be produced
   * [expectedOffset] the string offset that should be associated with the error
   * [source] the source to be scanned to produce the error
   */
  void _assertError(
      ScannerErrorCode expectedError, int expectedOffset, String source) {
    GatheringErrorListener listener = new GatheringErrorListener();
    _scanWithListener(source, listener);
    listener.assertErrors([
      new AnalysisError(null, expectedOffset, 1, expectedError,
          [source.codeUnitAt(expectedOffset)])
    ]);
  }

  /**
   * Assert that scanning the given [source] produces an error with the given
   * code, and also produces the given tokens.
   *
   * [expectedError] the error that should be produced
   * [expectedOffset] the string offset that should be associated with the error
   * [source] the source to be scanned to produce the error
   * [expectedTokens] the tokens that are expected to be in the source
   */
  void _assertErrorAndTokens(ScannerErrorCode expectedError, int expectedOffset,
      String source, List<Token> expectedTokens) {
    GatheringErrorListener listener = new GatheringErrorListener();
    Token token = _scanWithListener(source, listener);
    listener.assertErrors([
      new AnalysisError(null, expectedOffset, 1, expectedError,
          [source.codeUnitAt(expectedOffset)])
    ]);
    _checkTokens(token, expectedTokens);
  }

  /**
   * Assert that when scanned the given [source] contains a single keyword token
   * with the same lexeme as the original source.
   */
  void _assertKeywordToken(String source) {
    Token token = _scan(source);
    expect(token, isNotNull);
    expect(token.type, TokenType.KEYWORD);
    expect(token.offset, 0);
    expect(token.length, source.length);
    expect(token.lexeme, source);
    Object value = token.value();
    expect(value is Keyword, isTrue);
    expect((value as Keyword).syntax, source);
    token = _scan(" $source ");
    expect(token, isNotNull);
    expect(token.type, TokenType.KEYWORD);
    expect(token.offset, 1);
    expect(token.length, source.length);
    expect(token.lexeme, source);
    value = token.value();
    expect(value is Keyword, isTrue);
    expect((value as Keyword).syntax, source);
    expect(token.next.type, TokenType.EOF);
  }

  void _assertLineInfo(
      String source, List<ScannerTest_ExpectedLocation> expectedLocations) {
    GatheringErrorListener listener = new GatheringErrorListener();
    _scanWithListener(source, listener);
    listener.assertNoErrors();
    LineInfo info = listener.getLineInfo(new TestSource());
    expect(info, isNotNull);
    int count = expectedLocations.length;
    for (int i = 0; i < count; i++) {
      ScannerTest_ExpectedLocation expectedLocation = expectedLocations[i];
      LineInfo_Location location = info.getLocation(expectedLocation._offset);
      expect(location.lineNumber, expectedLocation._lineNumber,
          reason: 'Line number in location $i');
      expect(location.columnNumber, expectedLocation._columnNumber,
          reason: 'Column number in location $i');
    }
  }

  /**
   * Assert that the token scanned from the given [source] has the
   * [expectedType].
   */
  Token _assertToken(TokenType expectedType, String source) {
    Token originalToken = _scan(source);
    expect(originalToken, isNotNull);
    expect(originalToken.type, expectedType);
    expect(originalToken.offset, 0);
    expect(originalToken.length, source.length);
    expect(originalToken.lexeme, source);
    if (expectedType == TokenType.SCRIPT_TAG) {
      // Adding space before the script tag is not allowed, and adding text at
      // the end changes nothing.
      return originalToken;
    } else if (expectedType == TokenType.SINGLE_LINE_COMMENT) {
      // Adding space to an end-of-line comment changes the comment.
      Token tokenWithSpaces = _scan(" $source");
      expect(tokenWithSpaces, isNotNull);
      expect(tokenWithSpaces.type, expectedType);
      expect(tokenWithSpaces.offset, 1);
      expect(tokenWithSpaces.length, source.length);
      expect(tokenWithSpaces.lexeme, source);
      return originalToken;
    } else if (expectedType == TokenType.INT ||
        expectedType == TokenType.DOUBLE) {
      Token tokenWithLowerD = _scan("${source}d");
      expect(tokenWithLowerD, isNotNull);
      expect(tokenWithLowerD.type, expectedType);
      expect(tokenWithLowerD.offset, 0);
      expect(tokenWithLowerD.length, source.length);
      expect(tokenWithLowerD.lexeme, source);
      Token tokenWithUpperD = _scan("${source}D");
      expect(tokenWithUpperD, isNotNull);
      expect(tokenWithUpperD.type, expectedType);
      expect(tokenWithUpperD.offset, 0);
      expect(tokenWithUpperD.length, source.length);
      expect(tokenWithUpperD.lexeme, source);
    }
    Token tokenWithSpaces = _scan(" $source ");
    expect(tokenWithSpaces, isNotNull);
    expect(tokenWithSpaces.type, expectedType);
    expect(tokenWithSpaces.offset, 1);
    expect(tokenWithSpaces.length, source.length);
    expect(tokenWithSpaces.lexeme, source);
    expect(originalToken.next.type, TokenType.EOF);
    return originalToken;
  }

  /**
   * Assert that when scanned the given [source] contains a sequence of tokens
   * identical to the given list of [expectedTokens].
   */
  void _assertTokens(String source, List<Token> expectedTokens) {
    Token token = _scan(source);
    _checkTokens(token, expectedTokens);
  }

  void _checkTokens(Token firstToken, List<Token> expectedTokens) {
    expect(firstToken, isNotNull);
    Token token = firstToken;
    for (int i = 0; i < expectedTokens.length; i++) {
      Token expectedToken = expectedTokens[i];
      expect(token.type, expectedToken.type, reason: "Wrong type for token $i");
      expect(token.offset, expectedToken.offset,
          reason: "Wrong offset for token $i");
      expect(token.length, expectedToken.length,
          reason: "Wrong length for token $i");
      expect(token.lexeme, expectedToken.lexeme,
          reason: "Wrong lexeme for token $i");
      token = token.next;
      expect(token, isNotNull);
    }
    expect(token.type, TokenType.EOF);
  }

  Token _scan(String source, {bool genericMethodComments: false}) {
    GatheringErrorListener listener = new GatheringErrorListener();
    Token token = _scanWithListener(source, listener,
        genericMethodComments: genericMethodComments);
    listener.assertNoErrors();
    return token;
  }

  Token _scanWithListener(String source, GatheringErrorListener listener,
      {bool genericMethodComments: false}) {
    Scanner scanner =
        new Scanner(null, new CharSequenceReader(source), listener);
    if (genericMethodComments) {
      scanner.scanGenericMethodComments = true;
    }
    Token result = scanner.tokenize();
    listener.setLineInfo(new TestSource(), scanner.lineStarts);
    return result;
  }
}

/**
 * An `ExpectedLocation` encodes information about the expected location of a
 * given offset in source code.
 */
class ScannerTest_ExpectedLocation {
  final int _offset;

  final int _lineNumber;

  final int _columnNumber;

  ScannerTest_ExpectedLocation(
      this._offset, this._lineNumber, this._columnNumber);
}

/**
 * A `TokenStreamValidator` is used to validate the correct construction of a
 * stream of tokens.
 */
class TokenStreamValidator {
  /**
   * Validate that the stream of tokens that starts with the given [token] is
   * correct.
   */
  void validate(Token token) {
    StringBuffer buffer = new StringBuffer();
    _validateStream(buffer, token);
    if (buffer.length > 0) {
      fail(buffer.toString());
    }
  }

  void _validateStream(StringBuffer buffer, Token token) {
    if (token == null) {
      return;
    }
    Token previousToken = null;
    int previousEnd = -1;
    Token currentToken = token;
    while (currentToken != null && currentToken.type != TokenType.EOF) {
      _validateStream(buffer, currentToken.precedingComments);
      TokenType type = currentToken.type;
      if (type == TokenType.OPEN_CURLY_BRACKET ||
          type == TokenType.OPEN_PAREN ||
          type == TokenType.OPEN_SQUARE_BRACKET ||
          type == TokenType.STRING_INTERPOLATION_EXPRESSION) {
        if (currentToken is! BeginToken) {
          buffer.write("\r\nExpected BeginToken, found ");
          buffer.write(currentToken.runtimeType.toString());
          buffer.write(" ");
          _writeToken(buffer, currentToken);
        }
      }
      int currentStart = currentToken.offset;
      int currentLength = currentToken.length;
      int currentEnd = currentStart + currentLength - 1;
      if (currentStart <= previousEnd) {
        buffer.write("\r\nInvalid token sequence: ");
        _writeToken(buffer, previousToken);
        buffer.write(" followed by ");
        _writeToken(buffer, currentToken);
      }
      previousEnd = currentEnd;
      previousToken = currentToken;
      currentToken = currentToken.next;
    }
  }

  void _writeToken(StringBuffer buffer, Token token) {
    buffer.write("[");
    buffer.write(token.type);
    buffer.write(", '");
    buffer.write(token.lexeme);
    buffer.write("', ");
    buffer.write(token.offset);
    buffer.write(", ");
    buffer.write(token.length);
    buffer.write("]");
  }
}

@reflectiveTest
class TokenTypeTest extends EngineTestCase {
  void test_isOperator() {
    expect(TokenType.AMPERSAND.isOperator, isTrue);
    expect(TokenType.AMPERSAND_AMPERSAND.isOperator, isTrue);
    expect(TokenType.AMPERSAND_EQ.isOperator, isTrue);
    expect(TokenType.BANG.isOperator, isTrue);
    expect(TokenType.BANG_EQ.isOperator, isTrue);
    expect(TokenType.BAR.isOperator, isTrue);
    expect(TokenType.BAR_BAR.isOperator, isTrue);
    expect(TokenType.BAR_EQ.isOperator, isTrue);
    expect(TokenType.CARET.isOperator, isTrue);
    expect(TokenType.CARET_EQ.isOperator, isTrue);
    expect(TokenType.EQ.isOperator, isTrue);
    expect(TokenType.EQ_EQ.isOperator, isTrue);
    expect(TokenType.GT.isOperator, isTrue);
    expect(TokenType.GT_EQ.isOperator, isTrue);
    expect(TokenType.GT_GT.isOperator, isTrue);
    expect(TokenType.GT_GT_EQ.isOperator, isTrue);
    expect(TokenType.INDEX.isOperator, isTrue);
    expect(TokenType.INDEX_EQ.isOperator, isTrue);
    expect(TokenType.IS.isOperator, isTrue);
    expect(TokenType.LT.isOperator, isTrue);
    expect(TokenType.LT_EQ.isOperator, isTrue);
    expect(TokenType.LT_LT.isOperator, isTrue);
    expect(TokenType.LT_LT_EQ.isOperator, isTrue);
    expect(TokenType.MINUS.isOperator, isTrue);
    expect(TokenType.MINUS_EQ.isOperator, isTrue);
    expect(TokenType.MINUS_MINUS.isOperator, isTrue);
    expect(TokenType.PERCENT.isOperator, isTrue);
    expect(TokenType.PERCENT_EQ.isOperator, isTrue);
    expect(TokenType.PERIOD_PERIOD.isOperator, isTrue);
    expect(TokenType.PLUS.isOperator, isTrue);
    expect(TokenType.PLUS_EQ.isOperator, isTrue);
    expect(TokenType.PLUS_PLUS.isOperator, isTrue);
    expect(TokenType.QUESTION.isOperator, isTrue);
    expect(TokenType.SLASH.isOperator, isTrue);
    expect(TokenType.SLASH_EQ.isOperator, isTrue);
    expect(TokenType.STAR.isOperator, isTrue);
    expect(TokenType.STAR_EQ.isOperator, isTrue);
    expect(TokenType.TILDE.isOperator, isTrue);
    expect(TokenType.TILDE_SLASH.isOperator, isTrue);
    expect(TokenType.TILDE_SLASH_EQ.isOperator, isTrue);
  }

  void test_isUserDefinableOperator() {
    expect(TokenType.AMPERSAND.isUserDefinableOperator, isTrue);
    expect(TokenType.BAR.isUserDefinableOperator, isTrue);
    expect(TokenType.CARET.isUserDefinableOperator, isTrue);
    expect(TokenType.EQ_EQ.isUserDefinableOperator, isTrue);
    expect(TokenType.GT.isUserDefinableOperator, isTrue);
    expect(TokenType.GT_EQ.isUserDefinableOperator, isTrue);
    expect(TokenType.GT_GT.isUserDefinableOperator, isTrue);
    expect(TokenType.INDEX.isUserDefinableOperator, isTrue);
    expect(TokenType.INDEX_EQ.isUserDefinableOperator, isTrue);
    expect(TokenType.LT.isUserDefinableOperator, isTrue);
    expect(TokenType.LT_EQ.isUserDefinableOperator, isTrue);
    expect(TokenType.LT_LT.isUserDefinableOperator, isTrue);
    expect(TokenType.MINUS.isUserDefinableOperator, isTrue);
    expect(TokenType.PERCENT.isUserDefinableOperator, isTrue);
    expect(TokenType.PLUS.isUserDefinableOperator, isTrue);
    expect(TokenType.SLASH.isUserDefinableOperator, isTrue);
    expect(TokenType.STAR.isUserDefinableOperator, isTrue);
    expect(TokenType.TILDE.isUserDefinableOperator, isTrue);
    expect(TokenType.TILDE_SLASH.isUserDefinableOperator, isTrue);
  }
}