Add dedicated Wino.Mail.ViewModels.Tests coverage for WinoMailCollection (#812)

* Add WinoMailCollection tests in dedicated ViewModels test project

* Fix WinoMailCollection tests flattening without SelectMany

Wino.Mail.ViewModels.Tests/Collections/WinoMailCollectionTests.cs

@@ -0,0 +1,157 @@
+using FluentAssertions;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Interfaces;
+using Wino.Mail.ViewModels.Collections;
+using Wino.Mail.ViewModels.Data;
+using Xunit;
+
+namespace Wino.Mail.ViewModels.Tests.Collections;
+
+public class WinoMailCollectionTests
+{
+    [Fact]
+    public async Task AddAsync_ShouldAddSingleItemAsMailItemViewModel()
+    {
+        var sut = CreateCollection();
+        var mail = CreateMailCopy(threadId: "thread-1");
+
+        await sut.AddAsync(mail);
+
+        var items = FlattenItems(sut);
+        items.Should().ContainSingle().Which.Should().BeOfType<MailItemViewModel>();
+        sut.ContainsMailUniqueId(mail.UniqueId).Should().BeTrue();
+    }
+
+    [Fact]
+    public async Task AddAsync_ShouldKeepItemsSeparate_WhenThreadIdsDiffer()
+    {
+        var sut = CreateCollection();
+        var first = CreateMailCopy(threadId: "thread-1");
+        var second = CreateMailCopy(threadId: "thread-2");
+
+        await sut.AddAsync(first);
+        await sut.AddAsync(second);
+
+        var items = FlattenItems(sut);
+        items.Should().HaveCount(2);
+        items.Should().OnlyContain(item => item is MailItemViewModel);
+    }
+
+    [Fact]
+    public async Task AddAsync_ShouldConvertSingleItemToThread_WhenSecondItemWithSameThreadIdIsAdded()
+    {
+        var sut = CreateCollection();
+        var first = CreateMailCopy(threadId: "shared-thread", creationDate: DateTime.UtcNow.AddMinutes(-1));
+        var second = CreateMailCopy(threadId: "shared-thread", creationDate: DateTime.UtcNow);
+
+        await sut.AddAsync(first);
+        FlattenItems(sut).Should().ContainSingle().Which.Should().BeOfType<MailItemViewModel>();
+
+        await sut.AddAsync(second);
+
+        var items = FlattenItems(sut);
+        var threadItem = items.Should().ContainSingle().Which.Should().BeOfType<ThreadMailItemViewModel>().Subject;
+        threadItem.EmailCount.Should().Be(2);
+        threadItem.GetContainingIds().Should().BeEquivalentTo([first.UniqueId, second.UniqueId]);
+    }
+
+    [Fact]
+    public async Task RemoveAsync_ShouldConvertThreadToSingleItem_WhenThreadDropsToOneItem()
+    {
+        var sut = CreateCollection();
+        var first = CreateMailCopy(threadId: "shared-thread", creationDate: DateTime.UtcNow.AddMinutes(-1));
+        var second = CreateMailCopy(threadId: "shared-thread", creationDate: DateTime.UtcNow);
+
+        await sut.AddAsync(first);
+        await sut.AddAsync(second);
+
+        await sut.RemoveAsync(second);
+
+        var items = FlattenItems(sut);
+        var remainingItem = items.Should().ContainSingle().Which.Should().BeOfType<MailItemViewModel>().Subject;
+        remainingItem.MailCopy.UniqueId.Should().Be(first.UniqueId);
+
+        var container = sut.GetMailItemContainer(first.UniqueId);
+        container.Should().NotBeNull();
+        container.ThreadViewModel.Should().BeNull();
+    }
+
+    [Fact]
+    public async Task RemoveAsync_ShouldRemoveSingleItem()
+    {
+        var sut = CreateCollection();
+        var mail = CreateMailCopy(threadId: "thread-1");
+
+        await sut.AddAsync(mail);
+        await sut.RemoveAsync(mail);
+
+        FlattenItems(sut).Should().BeEmpty();
+        sut.ContainsMailUniqueId(mail.UniqueId).Should().BeFalse();
+    }
+
+    [Fact]
+    public async Task AddRangeAsync_ShouldCreateThreadsForItemsWithMatchingThreadId()
+    {
+        var sut = CreateCollection();
+
+        var threadAFirst = new MailItemViewModel(CreateMailCopy(threadId: "thread-a", creationDate: DateTime.UtcNow.AddMinutes(-10)));
+        var threadASecond = new MailItemViewModel(CreateMailCopy(threadId: "thread-a", creationDate: DateTime.UtcNow.AddMinutes(-9)));
+        var threadCFirst = new MailItemViewModel(CreateMailCopy(threadId: "thread-c", creationDate: DateTime.UtcNow.AddMinutes(-8)));
+        var threadCSecond = new MailItemViewModel(CreateMailCopy(threadId: "thread-c", creationDate: DateTime.UtcNow.AddMinutes(-7)));
+        var single = new MailItemViewModel(CreateMailCopy(threadId: "thread-b", creationDate: DateTime.UtcNow.AddMinutes(-6)));
+
+        await sut.AddRangeAsync([threadAFirst, threadASecond, threadCFirst, threadCSecond, single], clearIdCache: true);
+
+        var items = FlattenItems(sut);
+        items.Should().HaveCount(3);
+        items.Count(item => item is ThreadMailItemViewModel).Should().Be(2);
+        items.Count(item => item is MailItemViewModel).Should().Be(1);
+
+        var threadItems = items.OfType<ThreadMailItemViewModel>().ToList();
+        threadItems.Should().Contain(item => item.ThreadId == "thread-a" && item.EmailCount == 2);
+        threadItems.Should().Contain(item => item.ThreadId == "thread-c" && item.EmailCount == 2);
+    }
+
+    private static WinoMailCollection CreateCollection() => new()
+    {
+        CoreDispatcher = new ImmediateDispatcher()
+    };
+
+    private static List<IMailListItem> FlattenItems(WinoMailCollection collection)
+    {
+        var items = new List<IMailListItem>();
+
+        foreach (var group in collection.MailItems)
+        {
+            foreach (var item in group)
+            {
+                items.Add(item);
+            }
+        }
+
+        return items;
+    }
+
+    private static MailCopy CreateMailCopy(string threadId, DateTime? creationDate = null)
+        => new()
+        {
+            UniqueId = Guid.NewGuid(),
+            ThreadId = threadId,
+            CreationDate = creationDate ?? DateTime.UtcNow,
+            FromName = "Sender",
+            FromAddress = "sender@wino.dev",
+            Subject = "Subject",
+            PreviewText = "Preview",
+            FileId = Guid.NewGuid(),
+            FolderId = Guid.NewGuid()
+        };
+
+    private sealed class ImmediateDispatcher : IDispatcher
+    {
+        public Task ExecuteOnUIThread(Action action)
+        {
+            action();
+            return Task.CompletedTask;
+        }
+    }
+}

Wino.Mail.ViewModels.Tests/GlobalUsings.cs

@@ -0,0 +1,4 @@
+global using System;
+global using System.Collections.Generic;
+global using System.Linq;
+global using System.Threading.Tasks;

Wino.Mail.ViewModels.Tests/Wino.Mail.ViewModels.Tests.csproj

@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+    <Platforms>x86;x64;arm64</Platforms>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" />
+    <PackageReference Include="xunit" />
+    <PackageReference Include="xunit.runner.visualstudio">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="FluentAssertions" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Wino.Mail.ViewModels\Wino.Mail.ViewModels.csproj" />
+  </ItemGroup>
+</Project>

WinoMail.slnx

@@ -61,6 +61,11 @@
     <Platform Solution="*|x64" Project="x64" />
     <Platform Solution="*|x86" Project="x86" />
   </Project>
+  <Project Path="Wino.Mail.ViewModels.Tests/Wino.Mail.ViewModels.Tests.csproj">
+    <Platform Solution="*|arm64" Project="arm64" />
+    <Platform Solution="*|x64" Project="x64" />
+    <Platform Solution="*|x86" Project="x86" />
+  </Project>
   <Project Path="Wino.Mail.WinUI/Wino.Mail.WinUI.csproj" Id="bf340564-2cc8-486d-924d-8474cb5f3316">
     <Platform Solution="*|arm64" Project="ARM64" />
     <Platform Solution="*|x64" Project="x64" />