Merge pull request #44055 from sharwell/sequential-testing

Support sequential testing

eng/build.ps1

@@ -59,6 +59,7 @@ param (
   [switch][Alias('test')]$testDesktop,
   [switch]$testCoreClr,
   [switch]$testIOperation,
+  [switch]$sequential,
 
   [parameter(ValueFromRemainingArguments=$true)][string[]]$properties)
 
@@ -436,6 +437,10 @@ function TestUsingOptimizedRunner() {
     $args += " -test64"
   }
 
+  if ($sequential) {
+    $args += " -sequential"
+  }
+
   foreach ($dll in $dlls) {
     $args += " $dll"
   }

src/Tools/Source/RunTests/AssemblyScheduler.cs

@@ -196,19 +196,13 @@ internal AssemblyScheduler(Options options, int methodLimit = DefaultMethodLimit
             _methodLimit = methodLimit;
         }
 
-        internal IEnumerable<AssemblyInfo> Schedule(IEnumerable<string> assemblyPaths)
+        public IEnumerable<AssemblyInfo> Schedule(string assemblyPath, bool force = false)
         {
-            var list = new List<AssemblyInfo>();
-            foreach (var assemblyPath in assemblyPaths)
+            if (_options.Sequential)
             {
-                list.AddRange(Schedule(assemblyPath));
+                return new[] { CreateAssemblyInfo(assemblyPath) };
             }
 
-            return list;
-        }
-
-        public IEnumerable<AssemblyInfo> Schedule(string assemblyPath, bool force = false)
-        {
             var typeInfoList = GetTypeInfoList(assemblyPath);
             var assemblyInfoList = new List<AssemblyInfo>();
             var partitionList = new List<Partition>();

src/Tools/Source/RunTests/Options.cs

@@ -76,6 +76,11 @@ internal class Options
         /// </summary>
         public bool UseProcDump { get; set; }
 
+        /// <summary>
+        /// Disable partitioning and parallelization across test assemblies.
+        /// </summary>
+        public bool Sequential { get; set; }
+
         /// <summary>
         /// The directory which contains procdump.exe. 
         /// </summary>
@@ -214,6 +219,11 @@ bool isOption(string argument, string optionName, out string value)
                     opt.UseProcDump = false;
                     index++;
                 }
+                else if (comparer.Equals(current, "-sequential"))
+                {
+                    opt.Sequential = true;
+                    index++;
+                }
                 else
                 {
                     break;

src/Tools/Source/RunTests/TestRunner.cs

@@ -47,7 +47,7 @@ internal async Task<RunAllResult> RunAllAsync(IEnumerable<AssemblyInfo> assembly
             // Use 1.5 times the number of processors for unit tests, but only 1 processor for the open integration tests
             // since they perform actual UI operations (such as mouse clicks and sending keystrokes) and we don't want two
             // tests to conflict with one-another.
-            var max = (_options.TestVsi) ? 1 : (int)(Environment.ProcessorCount * 1.5);
+            var max = (_options.TestVsi || _options.Sequential) ? 1 : (int)(Environment.ProcessorCount * 1.5);
             var cacheCount = 0;
             var waiting = new Stack<AssemblyInfo>(assemblyInfoList);
             var running = new List<Task<TestResult>>();