测试 SQL 异常

Question

我有一个用于捕获 SqlException 的代码。我根据此处列出的答案编写了一个处理 SQLException 的测试：How to throw a SqlException when need for mocking and unit test?

 [TestMethod]
 public async Task TestFailJobOnSqlExceptionAsync()
 {      
     _context.Setup(x => x.CallSubOrchestratorAsync()
            .Throws(MakeSqlException());

     var orchestratorFunction = new OrchestratorFunction(_configuration.Object, _loggingRepository.Object);
     await orchestratorFunction.RunOrchestratorAsync(_context.Object, _executionContext.Object);

     _log.Verify(x => x.LogMessageAsync(
                         It.Is<LogMessage>(m => m.Message.StartsWith($"Caught SqlException")),
                         It.IsAny<VerbosityLevel>(),
                         It.IsAny<string>(),
                         It.IsAny<string>()), Times.Never());
 }

 public static SqlException MakeSqlException()
 {
     SqlException exception = null;
     try
     {
         SqlConnection conn = new SqlConnection(@"Data Source=.;Database=GUARANTEED_TO_FAIL;Connection Timeout=1");
         conn.Open();
     }
     catch (SqlException ex)
     {
         exception = ex;
     }
     return (exception);
 }

运行此程序时，我的测试失败并出现错误

测试方法 Services.Tests.TestFailJobOnSqlExceptionAsync 抛出异常： Microsoft.Data.SqlClient.SqlException：建立与 SQL Server 的连接时发生与网络相关或特定于实例的错误。服务器未找到或无法访问。验证实例名称是否正确以及 SQL Server 是否配置为允许远程连接。 （提供程序：命名管道提供程序，错误：40 - 无法打开与 SQL Server 的连接） ---> System.ComponentModel.Win32Exception：系统找不到指定的文件。

我错过了什么？

Answer 1

在编写单元测试时，您想要断言抛出特定异常，您将使用测试上方的

[ExpectedException(typeof(Microsoft.Data.SqlClient.SqlException))]

属性。

当属性丢失时，测试会失败，因为测试框架不理解您正在期待异常。

[TestMethod]
[ExpectedException(typeof(Microsoft.Data.SqlClient.SqlException))]
public async Task TestFailJobOnSqlExceptionAsync()
{      
     _context.Setup(x => x.CallSubOrchestratorAsync()
            .Throws(MakeSqlException());

     var orchestratorFunction = new OrchestratorFunction(_configuration.Object, _loggingRepository.Object);
     await orchestratorFunction.RunOrchestratorAsync(_context.Object, _executionContext.Object);

     _log.Verify(x => x.LogMessageAsync(
                         It.Is<LogMessage>(m => m.Message.StartsWith($"Caught SqlException")),
                         It.IsAny<VerbosityLevel>(),
                         It.IsAny<string>(),
                         It.IsAny<string>()), Times.Never());
}

如果您想验证记录器是否被调用，您需要在设置周围编写一个 try catch 块，直到验证方法为止。

[TestMethod]
public async Task TestFailJobOnSqlExceptionAsync()
{      

 try 
 {
     _context.Setup(x => x.CallSubOrchestratorAsync()
            .Throws(MakeSqlException());

     var orchestratorFunction = new OrchestratorFunction(_configuration.Object, _loggingRepository.Object);
     await orchestratorFunction.RunOrchestratorAsync(_context.Object, _executionContext.Object);
} catch(Exception)
       {

       }

     _log.Verify(x => x.LogMessageAsync(
                         It.Is<LogMessage>(m => m.Message.StartsWith($"Caught SqlException")),
                         It.IsAny<VerbosityLevel>(),
                         It.IsAny<string>(),
                         It.IsAny<string>()), Times.Never());
}