test/formatter_test.dart

// 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.

@TestOn("vm")
library dart_style.test.formatter_test;

import 'package:test/test.dart';

import 'package:dart_style/dart_style.dart';

import 'utils.dart';

void main() {
  testDirectory("comments");
  testDirectory("regression");
  testDirectory("selections");
  testDirectory("splitting");
  testDirectory("whitespace");

  test("throws a FormatterException on failed parse", () {
    var formatter = new DartFormatter();
    expect(() => formatter.format('wat?!'),
        throwsA(new isInstanceOf<FormatterException>()));
  });

  test("FormatterException.message() does not throw", () {
    // This is a regression test for #358 where an error whose position is
    // past the end of the source caused FormatterException to throw.
    try {
      new DartFormatter().format("library");
    } on FormatterException catch (err) {
      var message = err.message();
      expect(message, contains("Could not format"));
    }
  });

  test("FormatterException describes parse errors", () {
    try {
      new DartFormatter().format("""

      var a = some error;

      var b = another one;
      """, uri: "my_file.dart");

      fail("Should throw.");
    } on FormatterException catch (err) {
      var message = err.message();
      expect(message, contains("my_file.dart"));
      expect(message, contains("line 2"));
      expect(message, contains("line 4"));
    }
  });

  test("adds newline to unit", () {
    expect(new DartFormatter().format("var x = 1;"), equals("var x = 1;\n"));
  });

  test("adds newline to unit after trailing comment", () {
    expect(new DartFormatter().format("library foo; //zamm"),
        equals("library foo; //zamm\n"));
  });

  test("removes extra newlines", () {
    expect(
        new DartFormatter().format("var x = 1;\n\n\n"), equals("var x = 1;\n"));
  });

  test("does not add newline to statement", () {
    expect(new DartFormatter().formatStatement("var x = 1;"),
        equals("var x = 1;"));
  });

  test("fails if anything is after the statement", () {
    try {
      new DartFormatter().formatStatement("var x = 1;;");

      fail("Should throw.");
    } on FormatterException catch (ex) {
      expect(ex.errors.length, equals(1));
      expect(ex.errors.first.offset, equals(10));
    }
  });

  test('preserves initial indent', () {
    var formatter = new DartFormatter(indent: 3);
    expect(
        formatter.formatStatement('if (foo) {bar;}'),
        equals('   if (foo) {\n'
            '     bar;\n'
            '   }'));
  });

  group("line endings", () {
    test("uses given line ending", () {
      // Use zero width no-break space character as the line ending. We have
      // to use a whitespace character for the line ending as the formatter
      // will throw an error if it accidentally makes non-whitespace changes
      // as will occur
      var lineEnding = "\t";
      expect(new DartFormatter(lineEnding: lineEnding).format("var i = 1;"),
          equals("var i = 1;\t"));
    });

    test('infers \\r\\n if the first newline uses that', () {
      expect(new DartFormatter().format("var\r\ni\n=\n1;\n"),
          equals("var i = 1;\r\n"));
    });

    test('infers \\n if the first newline uses that', () {
      expect(new DartFormatter().format("var\ni\r\n=\r\n1;\r\n"),
          equals("var i = 1;\n"));
    });

    test('defaults to \\n if there are no newlines', () {
      expect(new DartFormatter().format("var i =1;"), equals("var i = 1;\n"));
    });

    test('handles Windows line endings in multiline strings', () {
      expect(
          new DartFormatter(lineEnding: "\r\n").formatStatement('  """first\r\n'
              'second\r\n'
              'third"""  ;'),
          equals('"""first\r\n'
              'second\r\n'
              'third""";'));
    });
  });

  test('throws an UnexpectedOutputException on non-whitespace changes', () {
    // Use an invalid line ending character to ensure the formatter will
    // attempt to make non-whitespace changes.
    var formatter = new DartFormatter(lineEnding: '%');
    expect(() => formatter.format("var i = 1;"),
        throwsA(new isInstanceOf<UnexpectedOutputException>()));
  });
}