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c# - 在 MSTest v2 中的并行测试之间共享 Entity Framework Core Database Context

问题描述

我正在尝试采用此方法在使用 MSTest v2 的多个测试中共享数据库连接，不幸的是它没有像 xUnit 这样的 Fixtures。因此我创建了一个静态类：

[TestClass]
static class DbContextFactory
{
    private static string ConnectionString = "Server=(localdb)\\MSSQLLocalDB;Initial Catalog=C4S_Test;ConnectRetryCount=0";

    /// <summary>
    /// Exposed connection for making shared transactions across multiple context instances possible
    /// </summary>
    public static DbConnection Connection;

    //called once before tests
    [AssemblyInitialize]
    public static void InitializeDbContext(TestContext context)
    {
        Connection = new SqlConnection(ConnectionString);
        Seed();
        Connection.Open();
    }

    public static C4S_DataContext CreateContext(DbTransaction transaction = null)
    {
        var context =
            new C4S_DataContext(new DbContextOptionsBuilder<C4S_DataContext>().UseSqlServer(Connection)
                .EnableSensitiveDataLogging().Options);

        if (transaction != null)
        {
            context.Database.UseTransaction(transaction);
        }

        return context;
    }

    [AssemblyCleanup]
    public static void Cleanup()
    {
        Connection.Close();
    }

    private static void Seed()
    {
        using (var context = CreateContext())
        {
            context.Database.EnsureDeleted();
            context.Database.EnsureCreated();

            //seed some data

            context.SaveChanges();
        }
    }

在测试中，我使用 C4S_DataContext 如下：

using (var dbContext = DbContextFactory.CreateContext())
{
    //work on dbContext
}

串行运行测试工作正常，但并行运行会以以下异常结束：

    Message: 
    Test method C4S.Model.Services.Tests.PortfolioGruppenServiceTests.GetPortfolioElementeInGruppeOrderedByBezeichnungAppTest threw exception: 
    System.InvalidOperationException: Internal connection fatal error.
  Stack Trace: 
    TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
    TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
    TdsParser.DrainData(TdsParserStateObject stateObj)
    TdsParser.ThrowUnsupportedCollationEncountered(TdsParserStateObject stateObj)
    TdsParser.GetCodePage(SqlCollation collation, TdsParserStateObject stateObj)
    TdsParser.TryCommonProcessMetaData(TdsParserStateObject stateObj, _SqlMetaData col)
    TdsParser.TryProcessMetaData(Int32 cColumns, TdsParserStateObject stateObj, _SqlMetaDataSet& metaData)
    TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
    SqlDataReader.TryConsumeMetaData()
    SqlDataReader.get_MetaData()
    SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
    SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds)
    SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite, String method)
    SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
    SqlCommand.ExecuteReader(CommandBehavior behavior)
    SqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
    DbCommand.ExecuteReader()
    RelationalCommand.Execute(IRelationalConnection connection, DbCommandMethod executeMethod, IReadOnlyDictionary`2 parameterValues)
    RelationalCommand.ExecuteReader(IRelationalConnection connection, IReadOnlyDictionary`2 parameterValues)
    SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
    Enumerable.TryGetFirst[TSource](IEnumerable`1 source, Boolean& found)
    lambda_method(Closure )
    ResultEnumerable`1.GetEnumerator()
    LinqOperatorProvider._TrackEntities[TOut,TIn](IEnumerable`1 results, QueryContext queryContext, IList`1 entityTrackingInfos, IList`1 entityAccessors)+MoveNext()
    Enumerable.TryGetFirst[TSource](IEnumerable`1 source, Boolean& found)
    Enumerable.First[TSource](IEnumerable`1 source)
    <>c__DisplayClass15_1`1.<CompileQueryCore>b__0(QueryContext qc)
    QueryCompiler.Execute[TResult](Expression query)
    EntityQueryProvider.Execute[TResult](Expression expression)
    Queryable.FirstOrDefault[TSource](IQueryable`1 source, Expression`1 predicate)

我假设存在并发问题，但无法弄清楚。您还需要使用文档中的打开连接了解以下有关 EF 行为的信息：

connection DbConnection 用于连接数据库的现有 DbConnection。如果连接处于打开状态，则 EF 不会打开或关闭连接。如果连接处于关闭状态，则 EF 将根据需要打开和关闭连接。来源

标签： c#testingentity-framework-coremstest

解决方案

如GitHub 上所述，根本不支持同时使用 SqlConnection

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