我有以下例外：

我用的是. NET 6（我仍然有错误），并认为这可能是与我在解决方案中使用的nugets的一些冲突。事实证明，即使在更新到. NET 7后，当我运行测试时，错误仍然存在。为了测试，我使用MSTest Framework和内存数据库（sqlite）进行集成测试，执行await context.Database.EnsureCreatedAsync();行出错，测试类如下：

public class SQLiteDatabaseContextFactory : IDisposable
{
    private DbConnection _connection;

    private DbContextOptions<DataContext> CreateOptions()
    {
        return new DbContextOptionsBuilder<DataContext>()
            .UseSqlite(_connection).Options;
    }

    public DataContext CreateContext()
    {
        if (_connection == null)
        {
            _connection = new SqliteConnection("DataSource=:memory:");
            _connection.Open();

            var options = CreateOptions();
            using var context = new DataContext(options);
            context.Database.EnsureCreated();
        }

        return new DataContext(CreateOptions());
    }

    public void Dispose()
    {
        if (_connection != null)
        {
            _connection.Dispose();
            _connection = null;
        }
    }
}

以及：

[TestClass]
public class SQLiteIntegrationTests
{
    [TestMethod]
    public async Task TestMethod_UsingSqliteInMemoryProvider_Success()
    {
        using var connection = new SqliteConnection("DataSource=:memory:");
        connection.Open();

        var options = new DbContextOptionsBuilder<DataContext>()
            .UseSqlite(connection) // Set the connection explicitly, so it won't be closed automatically by EF
            .Options;

        // Create the dabase schema
        // You can use MigrateAsync if you use Migrations
        using (var context = new DataContext(options))
        {
            //await context.Database.MigrateAsync();
            await context.Database.EnsureCreatedAsync();
        } // The connection is not closed, so the database still exists

        using (var context = new DataContext(options))
        {
            var user = new ManualClassifier()
            {
                FirstName = "First",
                LastName = "Last",
                Email = "example@gmail.com",
                Username = "firstlast123",
                PasswordHash = "5994471abb01112afcc18159f6cc74b4f511b99806da59b3caf",
                PasswordSalt = "5994471abb01112afcc18159f6cc74b4f511b99806da59b3caf"

            };
            context.ManualClassifiers.Add(user);
            await context.SaveChangesAsync();
        }

        using (var context = new DataContext(options))
        {
            var count = await context.ManualClassifiers.CountAsync();
            Assert.AreEqual(1, count);

            var u = await context.ManualClassifiers.FirstOrDefaultAsync(user => user.Email == "example@gmail.com");
            Assert.IsNotNull(u);
        }
    }
}

编辑：完整错误如下：

运行测试的项目的. csproj：

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net7.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="6.0.13" />
    <PackageReference Include="MSTest.TestFramework" Version="3.0.2" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\VSC.Repo\VSC.Repo.csproj" />
  </ItemGroup>

    <ItemGroup>
        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.7.1" />
        <PackageReference Include="MSTest.TestAdapter" Version="2.1.1" />
        <PackageReference Include="MSTest.TestFramework" Version="2.1.1" />
        <PackageReference Include="coverlet.collector" Version="1.3.0" />
    </ItemGroup>

</Project>

dbcontext类库. csproj：

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net7.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
    <ItemGroup>
        <FrameworkReference Include="Microsoft.AspNetCore.App" />
    </ItemGroup>
    <ItemGroup>
      <Folder Include="Services\" />
    </ItemGroup>
    <ItemGroup>
      <PackageReference Include="Microsoft.EntityFrameworkCore" Version="7.0.2" />
      <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="7.0.2">
        <PrivateAssets>all</PrivateAssets>
        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      </PackageReference>
      <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="7.0.2" />
      <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="7.0.2">
        <PrivateAssets>all</PrivateAssets>
        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      </PackageReference>
      <PackageReference Include="System.Configuration.ConfigurationManager" Version="7.0.0" />
    </ItemGroup>

</Project>

任何帮助弄清楚正在发生的事情将非常感谢。老实说，我不知道是什么原因造成的。