AppFlowy/frontend/app_flowy/packages/flowy_editor/test/delta_test.dart

import 'package:flutter_test/flutter_test.dart';
import 'package:flowy_editor/document/text_delta.dart';

void main() {
  TestWidgetsFlutterBinding.ensureInitialized();
  test('test delta', () {
    final delta = Delta(<TextOperation>[
      TextInsert('Gandalf', {
        'bold': true,
      }),
      TextInsert(' the '),
      TextInsert('Grey', {
        'color': '#ccc',
      })
    ]);

    final death = Delta().retain(12).insert("White", {
      'color': '#fff',
    }).delete(4);

    final restores = delta.compose(death);
    expect(restores.operations, <TextOperation>[
      TextInsert('Gandalf', {'bold': true}),
      TextInsert(' the '),
      TextInsert('White', {'color': '#fff'}),
    ]);
  });
  test('compose()', () {
    final a = Delta().insert('A');
    final b = Delta().insert('B');
    final expected = Delta().insert('B').insert('A');
    expect(a.compose(b), expected);
  });
  test('insert + retain', () {
    final a = Delta().insert('A');
    final b = Delta().retain(1, {
      'bold': true,
      'color': 'red',
    });
    final expected = Delta().insert('A', {
      'bold': true,
      'color': 'red',
    });
    expect(a.compose(b), expected);
  });
  test('insert + delete', () {
    final a = Delta().insert('A');
    final b = Delta().delete(1);
    final expected = Delta();
    expect(a.compose(b), expected);
  });
  test('delete + insert', () {
    final a = Delta().delete(1);
    final b = Delta().insert('B');
    final expected = Delta().insert('B').delete(1);
    expect(a.compose(b), expected);
  });
  test('delete + retain', () {
    final a = Delta().delete(1);
    final b = Delta().retain(1, {
      'bold': true,
      'color': 'red',
    });
    final expected = Delta().delete(1).retain(1, {
      'bold': true,
      'color': 'red',
    });
    expect(a.compose(b), expected);
  });
  test('delete + delete', () {
    final a = Delta().delete(1);
    final b = Delta().delete(1);
    final expected = Delta().delete(2);
    expect(a.compose(b), expected);
  });
  test('retain + insert', () {
    final a = Delta().retain(1, {
      'color': 'blue'
    });
    final b = Delta().insert('B');
    final expected = Delta().insert('B').retain(1, {
      'color': 'blue',
    });
    expect(a.compose(b), expected);
  });
  test('retain + retain', () {
    final a = Delta().retain(1, {
      'color': 'blue',
    });
    final b = Delta().retain(1, {
      'bold': true,
      'color': 'red',
    });
    final expected = Delta().retain(1, {
      'bold': true,
      'color': 'red',
    });
    expect(a.compose(b), expected);
  });
  test('retain + delete', () {
    final a = Delta().retain(1, {
      'color': 'blue',
    });
    final b = Delta().delete(1);
    final expected = Delta().delete(1);
    expect(a.compose(b), expected);
  });
  test('insert in middle of text', () {
    final a = Delta().insert('Hello');
    final b = Delta().retain(3).insert('X');
    final expected = Delta().insert('HelXlo');
    expect(a.compose(b), expected);
  });
  test('insert and delete ordering', () {
    final a = Delta().insert('Hello');
    final b = Delta().insert('Hello');
    final insertFirst = Delta().retain(3).insert('X').delete(1);
    final deleteFirst = Delta().retain(3).delete(1).insert('X');
    final expected = Delta().insert('HelXo');
    expect(a.compose(insertFirst), expected);
    expect(b.compose(deleteFirst), expected);
  });
  test('delete entire text', () {
    final a = Delta().retain(4).insert('Hello');
    final b = Delta().delete(9);
    final expected = Delta().delete(4);
    expect(a.compose(b), expected);
  });
  test('retain more than length of text', () {
    final a = Delta().insert('Hello');
    final b = Delta().retain(10);
    final expected = Delta().insert('Hello');
    expect(a.compose(b), expected);
  });
  test('retain start optimization', () {
    final a = Delta()
        .insert('A', {'bold': true})
        .insert('B')
        .insert('C', {'bold': true})
        .delete(1);
    final b = Delta().retain(3).insert('D');
    final expected = Delta()
        .insert('A', {'bold': true})
        .insert('B')
        .insert('C', {'bold': true})
        .insert('D')
        .delete(1);
    expect(a.compose(b), expected);
  });
  test('retain end optimization', () {
    final a = Delta()
        .insert('A', {'bold': true})
        .insert('B')
        .insert('C', {'bold': true});
    final b = Delta().delete(1);
    final expected = Delta().insert('B').insert('C', {'bold': true});
    expect(a.compose(b), expected);
  });
  test('retain end optimization join', () {
    final a = Delta()
        .insert('A', {'bold': true})
        .insert('B')
        .insert('C', {'bold': true})
        .insert('D')
        .insert('E', {'bold': true})
        .insert('F');
    final b = Delta().retain(1).delete(1);
    final expected = Delta()
        .insert('AC', {'bold': true})
        .insert('D')
        .insert('E', {'bold': true})
        .insert('F');
    expect(a.compose(b), expected);
  });
}