flutter_flutter/packages/flutter/test/rendering/flex_test.dart

// Copyright 2015 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.

import 'package:flutter/rendering.dart';
import 'package:test/test.dart';

import 'rendering_tester.dart';

void main() {
  test('Overconstrained flex', () {
    RenderDecoratedBox box = new RenderDecoratedBox(decoration: new BoxDecoration());
    RenderFlex flex = new RenderFlex(children: <RenderBox>[box]);
    layout(flex, constraints: const BoxConstraints(
      minWidth: 200.0, maxWidth: 200.0, minHeight: 200.0, maxHeight: 200.0)
    );

    expect(flex.size.width, equals(200.0), reason: "flex width");
    expect(flex.size.height, equals(200.0), reason: "flex height");
  });

  test('Vertical Overflow', () {
    RenderConstrainedBox flexible = new RenderConstrainedBox(
      additionalConstraints: const BoxConstraints.expand()
    );
    RenderFlex flex = new RenderFlex(
      direction: FlexDirection.vertical,
      children: <RenderBox>[
        new RenderConstrainedBox(additionalConstraints: new BoxConstraints.tightFor(height: 200.0)),
        flexible,
      ]
    );
    FlexParentData flexParentData = flexible.parentData;
    flexParentData.flex = 1;
    BoxConstraints viewport = new BoxConstraints(maxHeight: 100.0, maxWidth: 100.0);
    layout(flex, constraints: viewport);
    expect(flexible.size.height, equals(0.0));
    expect(flex.getMinIntrinsicHeight(viewport), equals(100.0));
    expect(flex.getMaxIntrinsicHeight(viewport), equals(100.0));
    expect(flex.getMinIntrinsicWidth(viewport), equals(100.0));
    expect(flex.getMaxIntrinsicWidth(viewport), equals(100.0));
  });

  test('Horizontal Overflow', () {
    RenderConstrainedBox flexible = new RenderConstrainedBox(
      additionalConstraints: const BoxConstraints.expand()
    );
    RenderFlex flex = new RenderFlex(
      direction: FlexDirection.horizontal,
      children: <RenderBox>[
        new RenderConstrainedBox(additionalConstraints: new BoxConstraints.tightFor(width: 200.0)),
        flexible,
      ]
    );
    FlexParentData flexParentData = flexible.parentData;
    flexParentData.flex = 1;
    BoxConstraints viewport = new BoxConstraints(maxHeight: 100.0, maxWidth: 100.0);
    layout(flex, constraints: viewport);
    expect(flexible.size.width, equals(0.0));
    expect(flex.getMinIntrinsicHeight(viewport), equals(100.0));
    expect(flex.getMaxIntrinsicHeight(viewport), equals(100.0));
    expect(flex.getMinIntrinsicWidth(viewport), equals(100.0));
    expect(flex.getMaxIntrinsicWidth(viewport), equals(100.0));
  });

  test('Vertical Flipped Constraints', () {
    RenderFlex flex = new RenderFlex(
      direction: FlexDirection.vertical,
      children: <RenderBox>[
        new RenderAspectRatio(aspectRatio: 1.0),
      ]
    );
    BoxConstraints viewport = new BoxConstraints(maxHeight: 200.0, maxWidth: 1000.0);
    layout(flex, constraints: viewport);
    expect(flex.getMaxIntrinsicWidth(viewport) , equals(1000.0));
  });

  // We can't right a horizontal version of the above test due to
  // RenderAspectRatio being height-in, width-out.

  test('Defaults', () {
    RenderFlex flex = new RenderFlex();
    expect(flex.alignItems, equals(FlexAlignItems.center));
    expect(flex.direction, equals(FlexDirection.horizontal));
  });

  test('Parent data', () {
    RenderDecoratedBox box1 = new RenderDecoratedBox(decoration: new BoxDecoration());
    RenderDecoratedBox box2 = new RenderDecoratedBox(decoration: new BoxDecoration());
    RenderFlex flex = new RenderFlex(children: <RenderBox>[box1, box2]);
    layout(flex, constraints: const BoxConstraints(
      minWidth: 0.0, maxWidth: 100.0, minHeight: 0.0, maxHeight: 100.0)
    );
    expect(box1.size.width, equals(0.0));
    expect(box1.size.height, equals(0.0));
    expect(box2.size.width, equals(0.0));
    expect(box2.size.height, equals(0.0));

    final FlexParentData box2ParentData = box2.parentData;
    box2ParentData.flex = 1;
    flex.markNeedsLayout();
    pumpFrame();
    expect(box1.size.width, equals(0.0));
    expect(box1.size.height, equals(0.0));
    expect(box2.size.width, equals(100.0));
    expect(box2.size.height, equals(0.0));
  });

  test('Stretch', () {
    RenderDecoratedBox box1 = new RenderDecoratedBox(decoration: new BoxDecoration());
    RenderDecoratedBox box2 = new RenderDecoratedBox(decoration: new BoxDecoration());
    RenderFlex flex = new RenderFlex();
    flex.setupParentData(box2);
    final FlexParentData box2ParentData = box2.parentData;
    box2ParentData.flex = 2;
    flex.addAll(<RenderBox>[box1, box2]);
    layout(flex, constraints: const BoxConstraints(
      minWidth: 0.0, maxWidth: 100.0, minHeight: 0.0, maxHeight: 100.0)
    );
    expect(box1.size.width, equals(0.0));
    expect(box1.size.height, equals(0.0));
    expect(box2.size.width, equals(100.0));
    expect(box2.size.height, equals(0.0));

    flex.alignItems = FlexAlignItems.stretch;
    pumpFrame();
    expect(box1.size.width, equals(0.0));
    expect(box1.size.height, equals(100.0));
    expect(box2.size.width, equals(100.0));
    expect(box2.size.height, equals(100.0));

    flex.direction = FlexDirection.vertical;
    pumpFrame();
    expect(box1.size.width, equals(100.0));
    expect(box1.size.height, equals(0.0));
    expect(box2.size.width, equals(100.0));
    expect(box2.size.height, equals(100.0));
  });
}