ObservableCollections/tests/ObservableCollections.Tests/ViewContainer.cs

using System;
using System.Collections.Generic;
using System.Collections.Specialized;

namespace ObservableCollections.Tests
{
    public struct ViewContainer<T> : IEquatable<ViewContainer<T>>, IComparable<ViewContainer<T>>
    {
        public ViewContainer(T value)
        {
            Value = value;
        }

        public T Value { get; }

        public static implicit operator ViewContainer<T>(T value) => new(value);

        public override int GetHashCode()
        {
            return Value.GetHashCode();
        }

        public int CompareTo(ViewContainer<T> other)
        {
            return Comparer<T>.Default.Compare(Value, other.Value);
        }

        public bool Equals(ViewContainer<T> other)
        {
            return EqualityComparer<T>.Default.Equals(Value, other.Value);
        }
    }

    public class TestFilter<T> : ISynchronizedViewFilter<T, ViewContainer<T>>
    {
        readonly Func<T, ViewContainer<T>, bool> filter;
        public List<(T, ViewContainer<T>)> CalledWhenTrue = new();
        public List<(T, ViewContainer<T>)> CalledWhenFalse = new();
        public List<(NotifyCollectionChangedAction changedAction, T value, ViewContainer<T> view, int index, int oldIndex)> CalledOnCollectionChanged = new();

        public TestFilter(Func<T, ViewContainer<T>, bool> filter)
        {
            this.filter = filter;
        }

        public void Clear()
        {
            CalledWhenTrue.Clear();
            CalledWhenFalse.Clear();
            CalledOnCollectionChanged.Clear();
        }

        public bool IsMatch(T value, ViewContainer<T> view)
        {
            return this.filter.Invoke(value, view);
        }

        public void OnCollectionChanged(NotifyCollectionChangedAction changedAction, T value, ViewContainer<T> view, in NotifyCollectionChangedEventArgs<T> eventArgs)
        {
            CalledOnCollectionChanged.Add((changedAction, value, view, eventArgs.NewStartingIndex, eventArgs.OldStartingIndex));
        }

        public void WhenTrue(T value, ViewContainer<T> view)
        {
            CalledWhenTrue.Add((value, view));
        }

        public void WhenFalse(T value, ViewContainer<T> view)
        {
            CalledWhenFalse.Add((value, view));
        }
    }

    public class TestFilter2<T> : ISynchronizedViewFilter<KeyValuePair<T, T>, ViewContainer<T>>
    {
        readonly Func<KeyValuePair<T, T>, ViewContainer<T>, bool> filter;
        public List<(KeyValuePair<T, T>, ViewContainer<T>)> CalledWhenTrue = new();
        public List<(KeyValuePair<T, T>, ViewContainer<T>)> CalledWhenFalse = new();
        public List<(NotifyCollectionChangedAction changedAction, KeyValuePair<T, T> value, ViewContainer<T> view)> CalledOnCollectionChanged = new();

        public TestFilter2(Func<KeyValuePair<T, T>, ViewContainer<T>, bool> filter)
        {
            this.filter = filter;
        }

        public void Clear()
        {
            CalledWhenTrue.Clear();
            CalledWhenFalse.Clear();
            CalledOnCollectionChanged.Clear();
        }

        public bool IsMatch(KeyValuePair<T, T> value, ViewContainer<T> view)
        {
            return this.filter.Invoke(value, view);
        }

        public void OnCollectionChanged(NotifyCollectionChangedAction changedAction, KeyValuePair<T, T> value, ViewContainer<T> view, in NotifyCollectionChangedEventArgs<KeyValuePair<T, T>> eventArgs)
        {
            CalledOnCollectionChanged.Add((changedAction, value, view));
        }

        public void WhenTrue(KeyValuePair<T, T> value, ViewContainer<T> view)
        {
            CalledWhenTrue.Add((value, view));
        }

        public void WhenFalse(KeyValuePair<T, T> value, ViewContainer<T> view)
        {
            CalledWhenFalse.Add((value, view));
        }
    }
}