repeat tests to stabilize coverage (#429)

* repeat

* repeat lfu

* undo lfu

---------

Author: bitfaster

BitFaster.Caching.UnitTests/Buffers/MpmcBoundedBufferSoakTests.cs

@@ -21,9 +21,12 @@ public MpmcBoundedBufferSoakTests(ITestOutputHelper testOutputHelper)
             this.testOutputHelper = testOutputHelper;
         }
 
-        [Fact]
-        public async Task WhenAddIsContendedBufferCanBeFilled()
+        [Theory]
+        [Repeat(3)]
+        public async Task WhenAddIsContendedBufferCanBeFilled(int iteration)
         {
+            this.testOutputHelper.WriteLine($"Iteration {iteration}");
+            
             await Threaded.Run(4, () =>
             {
                 while (buffer.TryAdd("hello") != BufferStatus.Full)

BitFaster.Caching.UnitTests/Buffers/MpscBoundedBufferSoakTests.cs

@@ -21,9 +21,12 @@ public MpscBoundedBufferSoakTests(ITestOutputHelper testOutputHelper)
             this.testOutputHelper = testOutputHelper;
         }
 
-        [Fact]
-        public async Task WhenAddIsContendedBufferCanBeFilled()
+        [Theory]
+        [Repeat(3)]
+        public async Task WhenAddIsContendedBufferCanBeFilled(int iteration)
         {
+            this.testOutputHelper.WriteLine($"Iteration {iteration}");
+
             await Threaded.Run(4, () =>
             {
                 while (buffer.TryAdd("hello") != BufferStatus.Full)

BitFaster.Caching.UnitTests/RepeatAttribute.cs

@@ -0,0 +1,29 @@
+using System.Linq;
+
+namespace BitFaster.Caching.UnitTests
+{
+    public sealed class RepeatAttribute : Xunit.Sdk.DataAttribute
+    {
+        private readonly int count;
+
+        public RepeatAttribute(int count)
+        {
+            if (count < 1)
+            {
+                throw new System.ArgumentOutOfRangeException(
+                    paramName: nameof(count),
+                    message: "Repeat count must be greater than 0."
+                    );
+            }
+            this.count = count;
+        }
+
+        public override System.Collections.Generic.IEnumerable<object[]> GetData(System.Reflection.MethodInfo testMethod)
+        {
+            foreach (var iterationNumber in Enumerable.Range(start: 1, count: this.count))
+            {
+                yield return new object[] { iterationNumber };
+            }
+        }
+    }
+}