private void RunTestIteration(SqlConnection con, SqlRandomizer rand, SqlRandomTable table, string tableName) { // random list of columns int columnCount = table.Columns.Count; int[] columnIndices = rand.NextIndices(columnCount); int selectedCount = rand.NextIntInclusive(1, maxValueInclusive: columnCount); StringBuilder selectBuilder = new StringBuilder(); table.GenerateSelectFromTableTSql(tableName, selectBuilder, columnIndices, 0, selectedCount); SqlCommand cmd = con.CreateCommand(); cmd.CommandType = CommandType.Text; cmd.CommandText = selectBuilder.ToString(); bool cancel = rand.Next(100) == 0; // in 1% of the cases, call Cancel if (cancel) { int cancelAfterMilliseconds = rand.Next(5); int cancelAfterSpinCount = rand.Next(1000); ThreadPool.QueueUserWorkItem((object state) => { for (int i = 0; cancel && i < cancelAfterMilliseconds; i++) { Thread.Sleep(1); } if (cancel && cancelAfterSpinCount > 0) { SpinWait.SpinUntil(() => false, new TimeSpan(cancelAfterSpinCount)); } if (cancel) { cmd.Cancel(); } }); } int readerRand = rand.NextIntInclusive(0, maxValueInclusive: 256); CommandBehavior readerBehavior = CommandBehavior.Default; if (readerRand % 10 == 0) { readerBehavior = CommandBehavior.SequentialAccess; } try { using (SqlDataReader reader = cmd.ExecuteReader(readerBehavior)) { int row = 0; while (reader.Read()) { int rowRand = rand.NextIntInclusive(); if (rowRand % 1000 == 0) { // abandon this reader break; } else if (rowRand % 25 == 0) { // skip the row row++; continue; } IList <object> expectedRow = table[row]; for (int c = 0; c < reader.FieldCount; c++) { if (rand.NextIntInclusive(0, maxValueInclusive: 10) == 0) { // skip the column continue; } int expectedTableColumn = columnIndices[c]; object expectedValue = expectedRow[expectedTableColumn]; if (table.Columns[expectedTableColumn].CanCompareValues) { Assert.True(expectedValue != null, "FAILED: Null is expected with CanCompareValues"); // read the value same way it was written object actualValue = table.Columns[expectedTableColumn].Read(reader, c, expectedValue.GetType()); Assert.True(table.Columns[expectedTableColumn].CompareValues(expectedValue, actualValue), string.Format("FAILED: Data Comparison Failure:\n{0}", table.Columns[expectedTableColumn].BuildErrorMessage(expectedValue, actualValue))); } } row++; } } // keep last - this will stop the cancel task, if it is still active cancel = false; } catch (SqlException e) { if (!cancel) { throw; } bool expected = false; foreach (SqlError error in e.Errors) { if (error.Message == _operationCanceledErrorMessage) { // ignore this one - expected if canceled expected = true; break; } else if (error.Message == _severeErrorMessage) { // A severe error occurred on the current command. The results, if any, should be discarded. expected = true; break; } } if (!expected) { // rethrow to the user foreach (SqlError error in e.Errors) { Console.WriteLine("{0} {1}", error.Number, error.Message); } throw; } } catch (InvalidOperationException e) { bool expected = false; if (e.Message == _operationCanceledErrorMessage) { // "Operation canceled" exception is raised as a SqlException (as one of SqlError objects) and as InvalidOperationException expected = true; } if (!expected) { throw; } } }