Reduce automated test crashes (#2968)

* Converted Threads to long-running Tasks

The key advantage is that exceptions propagate properly.
If a thread throws an exception (as a result of a failed test assertion, or otherwise) then the test host crashes and must be restarted.

* Corrected the instantiation of the cancellation task - missing state parameter.

* Changes to TestSqlCommandCancel, eliminating timing-specific cancellation behaviour testing.
This should also allow the test to run on both netcore and netfx.

* Responding to code review.
* Removed two unnecessary iterations from DatabaseHelper.
* Added explanatory comments to ApiShould.
* Switched to using Task.WaitAll rather than waiting for each Task in sequence.

* Improve cancellation detection

Cancellation can trigger one of several different errors, resulting in a flakier test.
Also ensure that the query always takes more than 150ms, ensuring that a quick query execution doesn't cause the test to fail.
Finally, make sure that we try to read everything from the SqlDataReader.

* Correcting previous merge

Author: edwardneal

src/Microsoft.Data.SqlClient/tests/ManualTests/AlwaysEncrypted/ApiShould.cs

@@ -290,10 +290,8 @@ public IEnumerator<object[]> GetEnumerator()
         {
             foreach (string connStrAE in DataTestUtility.AEConnStrings)
             {
-                yield return new object[] { connStrAE, @"ExecuteReader", 1 };
-                yield return new object[] { connStrAE, @"ExecuteReader", 3 };
-                yield return new object[] { connStrAE, @"ExecuteNonQuery", 1 };
-                yield return new object[] { connStrAE, @"ExecuteNonQuery", 3 };
+                yield return new object[] { connStrAE, @"ExecuteReader" };
+                yield return new object[] { connStrAE, @"ExecuteNonQuery" };
             }
         }
         IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();

src/Microsoft.Data.SqlClient/tests/ManualTests/AlwaysEncrypted/TestFixtures/DatabaseHelper.cs

@@ -171,7 +171,7 @@ public class ConnectionWorker : IDisposable
             private static List<ConnectionWorker> s_workerList = new();
             private ManualResetEventSlim _doneEvent = new(false);
             private double _timeElapsed;
-            private Thread _thread;
+            private Task _task;
             private string _connectionString;
             private int _numOfTry;
 
@@ -180,7 +180,7 @@ public ConnectionWorker(string connectionString, int numOfTry)
                 s_workerList.Add(this);
                 _connectionString = connectionString;
                 _numOfTry = numOfTry;
-                _thread = new Thread(new ThreadStart(SqlConnectionOpen));
+                _task = new Task(SqlConnectionOpen, TaskCreationOptions.LongRunning);
             }
 
             public static List<ConnectionWorker> WorkerList => s_workerList;
@@ -191,7 +191,7 @@ public static void Start()
             {
                 foreach (ConnectionWorker w in s_workerList)
                 {
-                    w._thread.Start();
+                    w._task.Start();
                 }
             }
 

src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/ConnectivityTests/ConnectivityTest.cs

@@ -6,6 +6,7 @@
 using System.Collections.Generic;
 using System.Data;
 using System.Threading;
+using System.Threading.Tasks;
 using Xunit;
 
 namespace Microsoft.Data.SqlClient.ManualTesting.Tests
@@ -28,17 +29,14 @@ public static void TestMultipleConnectionToMirroredServer()
                 builder.ConnectTimeout = 0;
 
                 TestWorker worker = new TestWorker(builder.ConnectionString);
-                Thread childThread = new Thread(() => worker.TestMultipleConnection());
-                childThread.Start();
+                Task childTask = Task.Factory.StartNew(() => worker.TestMultipleConnection(), TaskCreationOptions.LongRunning);
 
                 if (workerCompletedEvent.WaitOne(10000))
                 {
-                    childThread.Join();
+                    childTask.Wait();
                 }
                 else
                 {
-                    // currently Thread.Abort() throws PlatformNotSupportedException in CoreFx.
-                    childThread.Interrupt();
                     throw new Exception("SqlConnection could not open and close successfully in timely manner. Possibly connection hangs.");
                 }
             }

src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/MirroringTest/ConnectionOnMirroringTest.cs

@@ -8,6 +8,7 @@
 using System.Data;
 using System.Data.SqlTypes;
 using System.Threading;
+using System.Threading.Tasks;
 using Xunit;
 using System.Globalization;
 
@@ -957,30 +958,19 @@ private static void EnableOptimizedParameterBinding_ReturnSucceeds()
         [ConditionalFact(typeof(DataTestUtility), nameof(DataTestUtility.AreConnStringsSetup))]
         public static void ClosedConnection_SqlParameterValueTest()
         {
-            var threads = new List<Thread>();
-            for (int i = 0; i < 100; i++)
+            var tasks = new Task[100];
+            for (int i = 0; i < tasks.Length; i++)
             {
-                var t = new Thread(() =>
+                var t = Task.Factory.StartNew(() =>
                 {
                     for (int j = 0; j < 1000; j++)
                     {
-                        try
-                        {
-                            RunParameterTest();
-                        }
-                        catch (Exception e)
-                        {
-                            Assert.Fail($"Unexpected exception occurred: {e.Message}");
-                        }
+                        RunParameterTest();
                     }
-                });
-                t.Start();
-                threads.Add(t);
-            }
-            for (int i = 0; i < threads.Count; i++)
-            {
-                threads[i].Join();
+                }, TaskCreationOptions.LongRunning);
+                tasks[i] = t;
             }
+            Task.WaitAll(tasks);
         }
 
         private static void RunParameterTest()
@@ -998,7 +988,7 @@ private static void RunParameterTest()
             cm.Parameters.Add(new SqlParameter("@id2", SqlDbType.UniqueIdentifier) { Direction = ParameterDirection.Output });
             try
             {
-                System.Threading.Tasks.Task<int> task = cm.ExecuteNonQueryAsync(cancellationToken.Token);
+                Task<int> task = cm.ExecuteNonQueryAsync(cancellationToken.Token);
                 task.Wait();
             }
             catch (Exception)

src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/ParameterTest/ParametersTest.cs

@@ -8,6 +8,7 @@
 using System.Diagnostics;
 using System.Text;
 using System.Threading;
+using System.Threading.Tasks;
 using Xunit;
 
 namespace Microsoft.Data.SqlClient.ManualTesting.Tests
@@ -70,8 +71,7 @@ public void TestMain()
             {
                 for (int tcount = 0; tcount < ThreadCountDefault; tcount++)
                 {
-                    Thread t = new Thread(TestThread);
-                    t.Start();
+                    _ = Task.Factory.StartNew(TestThread, TaskCreationOptions.LongRunning);
                 }
             }