// Copyright 2014 The Flutter 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:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';

void main() {
  // DOWN (default)

  testWidgets('Column with one flexible child', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // Default is MainAxisAlignment.start so children so the children's
    // top edges should be at 0, 100, 500, child2's height should be 400.
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          Expanded(child: SizedBox(key: child1Key, width: 100.0, height: 100.0)),
          SizedBox(key: child2Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(0.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(400.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(100.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(500.0));
  });

  testWidgets('Column with default main axis parameters', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // Default is MainAxisAlignment.start so children so the children's
    // top edges should be at 0, 100, 200
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          SizedBox(key: child1Key, width: 100.0, height: 100.0),
          SizedBox(key: child2Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(0.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(100.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(200.0));
  });

  testWidgets('Column with MainAxisAlignment.center', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // The 100x100 children's top edges should be at 200, 300
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        mainAxisAlignment: MainAxisAlignment.center,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          SizedBox(key: child1Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(200.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(300.0));
  });

  testWidgets('Column with MainAxisAlignment.end', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // The 100x100 children's top edges should be at 300, 400, 500.
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        mainAxisAlignment: MainAxisAlignment.end,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          SizedBox(key: child1Key, width: 100.0, height: 100.0),
          SizedBox(key: child2Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(300.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(400.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(500.0));
  });

  testWidgets('Column with MainAxisAlignment.spaceBetween', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // The 100x100 children's top edges should be at 0, 250, 500
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          SizedBox(key: child1Key, width: 100.0, height: 100.0),
          SizedBox(key: child2Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(0.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(250.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(500.0));
  });

  testWidgets('Column with MainAxisAlignment.spaceAround', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');
    const Key child3Key = Key('child3');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // The 100x100 children's top edges should be at 25, 175, 325, 475
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        mainAxisAlignment: MainAxisAlignment.spaceAround,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          SizedBox(key: child1Key, width: 100.0, height: 100.0),
          SizedBox(key: child2Key, width: 100.0, height: 100.0),
          SizedBox(key: child3Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(25.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(175.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(325.0));

    renderBox = tester.renderObject(find.byKey(child3Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(475.0));
  });

  testWidgets('Column with MainAxisAlignment.spaceEvenly', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // The 100x20 children's top edges should be at 135, 290, 445
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 20.0),
          SizedBox(key: child1Key, width: 100.0, height: 20.0),
          SizedBox(key: child2Key, width: 100.0, height: 20.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(20.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(135.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(20.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(290.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(20.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(445.0));
  });

  testWidgets('Column and MainAxisSize.min', (WidgetTester tester) async {
    const Key flexKey = Key('flexKey');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    await tester.pumpWidget(Center(
      child: Column(
        key: flexKey,
        children: const <Widget>[
          SizedBox(width: 100.0, height: 100.0),
          SizedBox(width: 100.0, height: 150.0),
        ],
      ),
    ));
    RenderBox renderBox = tester.renderObject(find.byKey(flexKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    // Column with MainAxisSize.min without flexible children shrink wraps.
    await tester.pumpWidget(Center(
      child: Column(
        key: flexKey,
        mainAxisSize: MainAxisSize.min,
        children: const <Widget>[
          SizedBox(width: 100.0, height: 100.0),
          SizedBox(width: 100.0, height: 150.0),
        ],
      ),
    ));
    renderBox = tester.renderObject(find.byKey(flexKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(250.0));
  });

  testWidgets('Column MainAxisSize.min layout at zero size', (WidgetTester tester) async {
    const Key childKey = Key('childKey');

    await tester.pumpWidget(Center(
      child: SizedBox(
        width: 0.0,
        height: 0.0,
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: const <Widget>[
            SizedBox(
              key: childKey,
              width: 100.0,
              height: 100.0,
            ),
          ],
        ),
      ),
    ));

    final RenderBox renderBox = tester.renderObject(find.byKey(childKey));
    expect(renderBox.size.width, equals(0.0));
    expect(renderBox.size.height, equals(100.0));
  });


  // UP

  testWidgets('Column with one flexible child', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // Default is MainAxisAlignment.start so children so the children's
    // bottom edges should be at 0, 100, 500 from bottom, child2's height should be 400.
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        verticalDirection: VerticalDirection.up,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          Expanded(child: SizedBox(key: child1Key, width: 100.0, height: 100.0)),
          SizedBox(key: child2Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(500.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(400.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(100.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(0.0));
  });

  testWidgets('Column with default main axis parameters', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // Default is MainAxisAlignment.start so children so the children's
    // bottom edges should be at 0, 100, 200 from bottom
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        verticalDirection: VerticalDirection.up,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          SizedBox(key: child1Key, width: 100.0, height: 100.0),
          SizedBox(key: child2Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(500.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(400.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(300.0));
  });

  testWidgets('Column with MainAxisAlignment.center', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // The 100x100 children's bottom edges should be at 200, 300 from bottom
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        mainAxisAlignment: MainAxisAlignment.center,
        verticalDirection: VerticalDirection.up,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          SizedBox(key: child1Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(300.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(200.0));
  });

  testWidgets('Column with MainAxisAlignment.end', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // The 100x100 children's bottom edges should be at 300, 400, 500 from bottom.
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        mainAxisAlignment: MainAxisAlignment.end,
        verticalDirection: VerticalDirection.up,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          SizedBox(key: child1Key, width: 100.0, height: 100.0),
          SizedBox(key: child2Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(200.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(100.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(0.0));
  });

  testWidgets('Column with MainAxisAlignment.spaceBetween', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // The 100x100 children's bottom edges should be at 0, 250, 500 from bottom
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        verticalDirection: VerticalDirection.up,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          SizedBox(key: child1Key, width: 100.0, height: 100.0),
          SizedBox(key: child2Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(500.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(250.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(0.0));
  });

  testWidgets('Column with MainAxisAlignment.spaceAround', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');
    const Key child3Key = Key('child3');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // The 100x100 children's bottom edges should be at 25, 175, 325, 475 from bottom
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        mainAxisAlignment: MainAxisAlignment.spaceAround,
        verticalDirection: VerticalDirection.up,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 100.0),
          SizedBox(key: child1Key, width: 100.0, height: 100.0),
          SizedBox(key: child2Key, width: 100.0, height: 100.0),
          SizedBox(key: child3Key, width: 100.0, height: 100.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(500.0 - 25.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(500.0 - 175.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(500.0 - 325.0));

    renderBox = tester.renderObject(find.byKey(child3Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(100.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(500.0 - 475.0));
  });

  testWidgets('Column with MainAxisAlignment.spaceEvenly', (WidgetTester tester) async {
    const Key columnKey = Key('column');
    const Key child0Key = Key('child0');
    const Key child1Key = Key('child1');
    const Key child2Key = Key('child2');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    // The 100x20 children's bottom edges should be at 135, 290, 445 from bottom
    await tester.pumpWidget(Center(
      child: Column(
        key: columnKey,
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        verticalDirection: VerticalDirection.up,
        children: const <Widget>[
          SizedBox(key: child0Key, width: 100.0, height: 20.0),
          SizedBox(key: child1Key, width: 100.0, height: 20.0),
          SizedBox(key: child2Key, width: 100.0, height: 20.0),
        ],
      ),
    ));

    RenderBox renderBox;
    BoxParentData boxParentData;

    renderBox = tester.renderObject(find.byKey(columnKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    renderBox = tester.renderObject(find.byKey(child0Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(20.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(600.0 - 135.0 - 20.0));

    renderBox = tester.renderObject(find.byKey(child1Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(20.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(600.0 - 290.0 - 20.0));

    renderBox = tester.renderObject(find.byKey(child2Key));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(20.0));
    boxParentData = renderBox.parentData! as BoxParentData;
    expect(boxParentData.offset.dy, equals(600.0 - 445.0 - 20.0));
  });

  testWidgets('Column and MainAxisSize.min', (WidgetTester tester) async {
    const Key flexKey = Key('flexKey');

    // Default is MainAxisSize.max so the Column should be as high as the test: 600.
    await tester.pumpWidget(Center(
      child: Column(
        key: flexKey,
        verticalDirection: VerticalDirection.up,
        children: const <Widget>[
          SizedBox(width: 100.0, height: 100.0),
          SizedBox(width: 100.0, height: 150.0),
        ],
      ),
    ));
    RenderBox renderBox = tester.renderObject(find.byKey(flexKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(600.0));

    // Column with MainAxisSize.min without flexible children shrink wraps.
    await tester.pumpWidget(Center(
      child: Column(
        key: flexKey,
        mainAxisSize: MainAxisSize.min,
        verticalDirection: VerticalDirection.up,
        children: const <Widget>[
          SizedBox(width: 100.0, height: 100.0),
          SizedBox(width: 100.0, height: 150.0),
        ],
      ),
    ));
    renderBox = tester.renderObject(find.byKey(flexKey));
    expect(renderBox.size.width, equals(100.0));
    expect(renderBox.size.height, equals(250.0));
  });

  testWidgets('Column MainAxisSize.min layout at zero size', (WidgetTester tester) async {
    const Key childKey = Key('childKey');

    await tester.pumpWidget(Center(
      child: SizedBox(
        width: 0.0,
        height: 0.0,
        child: Column(
          mainAxisSize: MainAxisSize.min,
          verticalDirection: VerticalDirection.up,
          children: const <Widget>[
            SizedBox(
              key: childKey,
              width: 100.0,
              height: 100.0,
            ),
          ],
        ),
      ),
    ));

    final RenderBox renderBox = tester.renderObject(find.byKey(childKey));
    expect(renderBox.size.width, equals(0.0));
    expect(renderBox.size.height, equals(100.0));
  });
}