Add argument checking for the overloads

Rx.NET/Source/tests/Tests.System.Reactive/Tests/Linq/Observable/RefCountTest.cs

@@ -40,6 +40,10 @@ namespace ReactiveTests.Tests
         public void RefCount_ArgumentChecking()
         {
             ReactiveAssert.Throws<ArgumentNullException>(() => Observable.RefCount<int>(null));
+            ReactiveAssert.Throws<ArgumentNullException>(() => Observable.RefCount<int>(null, 2));
+            ReactiveAssert.Throws<ArgumentOutOfRangeException>(() => Observable.RefCount(Observable.Never<int>().Publish(), 0));
+            ReactiveAssert.Throws<ArgumentOutOfRangeException>(() => Observable.RefCount(Observable.Never<int>().Publish(), -1));
+            ReactiveAssert.Throws<ArgumentOutOfRangeException>(() => Observable.RefCount(Observable.Never<int>().Publish(), -2));
         }
 
         [Fact]
@@ -242,6 +246,15 @@ namespace ReactiveTests.Tests
         public void LazyRefCount_ArgumentChecking()
         {
             ReactiveAssert.Throws<ArgumentNullException>(() => Observable.RefCount<int>(null, TimeSpan.FromSeconds(2)));
+            ReactiveAssert.Throws<ArgumentNullException>(() => Observable.RefCount<int>(null, TimeSpan.FromSeconds(2), Scheduler.Default));
+            ReactiveAssert.Throws<ArgumentNullException>(() => Observable.RefCount<int>(null, 2, TimeSpan.FromSeconds(2)));
+            ReactiveAssert.Throws<ArgumentNullException>(() => Observable.RefCount<int>(null, 2, TimeSpan.FromSeconds(2)));
+            ReactiveAssert.Throws<ArgumentNullException>(() => Observable.RefCount(Observable.Never<int>().Publish(), TimeSpan.FromSeconds(2), null));
+            ReactiveAssert.Throws<ArgumentOutOfRangeException>(() => Observable.RefCount(Observable.Never<int>().Publish(), 0, TimeSpan.FromSeconds(2)));
+            ReactiveAssert.Throws<ArgumentOutOfRangeException>(() => Observable.RefCount(Observable.Never<int>().Publish(), -1, TimeSpan.FromSeconds(2)));
+            ReactiveAssert.Throws<ArgumentNullException>(() => Observable.RefCount(Observable.Never<int>().Publish(), 2, TimeSpan.FromSeconds(2), null));
+            ReactiveAssert.Throws<ArgumentOutOfRangeException>(() => Observable.RefCount(Observable.Never<int>().Publish(), 0, TimeSpan.FromSeconds(2), Scheduler.Default));
+            ReactiveAssert.Throws<ArgumentOutOfRangeException>(() => Observable.RefCount(Observable.Never<int>().Publish(), -1, TimeSpan.FromSeconds(2), Scheduler.Default));
         }
 
         [Fact]