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Use Xunit.DepdencyInjection Transformation test project

Use Xunit.DependencyInjection Transformation test project

Intro

This article has been delayed for a long time , It has been introduced before Xunit.DependencyInjection This project , This project was written by a master Xunit Based on Microsoft GenericHost and An extension library for dependency injection implementation , It can make it easier for you to implement dependency injection in test projects , And I think another good point is that it can better control the operation process , For example, many initialization operations are done before starting the test , Better process control .

Recently, most of our company's testing projects are based on Xunit.DependencyInjection Transformed , The effect is very good .

Recently, I started my test project manually from the original one Web Host It's based on Xunit.DepdencyInjection To use , At the same time, it is also preparing for the update of integration test of a project of our company , It's delicious to use ~

I think Xunit.DependencyInjection Solved my two big pain points , One is that dependency injection code doesn't write well , One is a simpler process control process , Here is a general introduction to

XUnit.DependencyInjection Workflow

Xunit.DepdencyInjection The main process is DependencyInjectionTestFramework in , See https://github.com/pengweiqhca/Xunit.DependencyInjection/blob/7.0/Xunit.DependencyInjection/DependencyInjectionTestFramework.cs

First of all, I will try to find the... In the project Startup , This Startup Very similar to asp.net core Medium Startup, Almost exactly , It's just a little different , Startup Dependency injection is not supported , Can not be like asp.net core Put in a like that IConfiguration Object to get the configuration , besides , and asp.net core Of Startup Have the same experience , If you can't find this Startup There are no services or special configurations that need dependency injection , Use it directly Xunit The original XunitTestFrameworkExecutor, If you find it Startup From Startup Configure in the agreed method Host, Registration service and initialization configuration process , Finally using DependencyInjectionTestFrameworkExecutor Carry out our test case.

The source code parsing

The source code uses C#8 Some of the new grammar of , The code is very simple , The following code uses nullable reference types ：

DependencyInjectionTestFramework Source code

public sealed class DependencyInjectionTestFramework : XunitTestFramework{ public DependencyInjectionTestFramework(IMessageSink messageSink) : base(messageSink) { } protected override ITestFrameworkExecutor CreateExecutor(AssemblyName assemblyName) {  IHost? host = null;  try  {   //  obtain  Startup  example    var startup = StartupLoader.CreateStartup(StartupLoader.GetStartupType(assemblyName));   if (startup == null) return new XunitTestFrameworkExecutor(assemblyName, SourceInformationProvider, DiagnosticMessageSink);   //  establish  HostBuilder   var hostBuilder = StartupLoader.CreateHostBuilder(startup, assemblyName) ??        new HostBuilder().ConfigureHostConfiguration(builder =>         builder.AddInMemoryCollection(new Dictionary<string, string> { { HostDefaults.ApplicationKey, assemblyName.Name } }));   //  call  Startup  Medium  ConfigureHost  Method configuration  Host   StartupLoader.ConfigureHost(hostBuilder, startup);   //  call  Startup  Medium  ConfigureServices  Method register service    StartupLoader.ConfigureServices(hostBuilder, startup);   //  Register default service , structure  Host   host = hostBuilder.ConfigureServices(services => services     .AddSingleton(DiagnosticMessageSink)     .TryAddSingleton<ITestOutputHelperAccessor, TestOutputHelperAccessor>())    .Build();   //  call  Startup  Medium  Configure  Method to initialize    StartupLoader.Configure(host.Services, startup);   //  return  testcase executor, Ready to start running test cases    return new DependencyInjectionTestFrameworkExecutor(host, null,    assemblyName, SourceInformationProvider, DiagnosticMessageSink);  }  catch (Exception e)  {   return new DependencyInjectionTestFrameworkExecutor(host, e,    assemblyName, SourceInformationProvider, DiagnosticMessageSink);  } }}

StarpupLoader Source code

public static Type? GetStartupType(AssemblyName assemblyName){ var assembly = Assembly.Load(assemblyName); var attr = assembly.GetCustomAttribute<StartupTypeAttribute>(); if (attr == null) return assembly.GetType($"{assemblyName.Name}.Startup"); if (attr.AssemblyName != null) assembly = Assembly.Load(attr.AssemblyName); return assembly.GetType(attr.TypeName) ?? throw new InvalidOperationException($"Can't load type {attr.TypeName} in '{assembly.FullName}'");}public static object? CreateStartup(Type? startupType){ if (startupType == null) return null; var ctors = startupType.GetConstructors(); if (ctors.Length != 1 || ctors[0].GetParameters().Length != 0)  throw new InvalidOperationException($"'{startupType.FullName}' must have a single public constructor and the constructor without parameters."); return Activator.CreateInstance(startupType);}public static IHostBuilder? CreateHostBuilder(object startup, AssemblyName assemblyName){ var method = FindMethod(startup.GetType(), nameof(CreateHostBuilder), typeof(IHostBuilder)); if (method == null) return null; var parameters = method.GetParameters(); if (parameters.Length == 0)  return (IHostBuilder)method.Invoke(startup, Array.Empty<object>()); if (parameters.Length > 1 || parameters[0].ParameterType != typeof(AssemblyName))  throw new InvalidOperationException($"The '{method.Name}' method of startup type '{startup.GetType().FullName}' must without parameters or have the single 'AssemblyName' parameter."); return (IHostBuilder)method.Invoke(startup, new object[] { assemblyName });}public static void ConfigureHost(IHostBuilder builder, object startup){ var method = FindMethod(startup.GetType(), nameof(ConfigureHost)); if (method == null) return; var parameters = method.GetParameters(); if (parameters.Length != 1 || parameters[0].ParameterType != typeof(IHostBuilder))  throw new InvalidOperationException($"The '{method.Name}' method of startup type '{startup.GetType().FullName}' must have the single 'IHostBuilder' parameter."); method.Invoke(startup, new object[] { builder });}public static void ConfigureServices(IHostBuilder builder, object startup){ var method = FindMethod(startup.GetType(), nameof(ConfigureServices)); if (method == null) return; var parameters = method.GetParameters(); builder.ConfigureServices(parameters.Length switch {  1 when parameters[0].ParameterType == typeof(IServiceCollection) =>  (.........