add missing Average() test

src/s-z/Sma/Sma.Utilities.cs

@@ -22,19 +22,20 @@ public static partial class Sma
     /// if incalculable <see langword="double.NaN"/>
     /// values are in range.
     /// </returns>
-    internal static double? Average<T>(
+    public static double? Average<T>(
         this IReadOnlyList<T> values,
         int lookbackPeriods,
         int? endIndex = null)
         where T : IReusable
+    {
+        ArgumentNullException.ThrowIfNull(values);
 
-        // TODO: unused SMA utility, either make public or remove
-
-        => Increment(
+        return Increment(
             values,
             lookbackPeriods,
             endIndex ?? values.Count - 1)
            .NaN2Null();
+    }
 
     /// <summary>
     /// Simple moving average calculation

tests/external/integration/GlobalUsings.cs

@@ -1 +1 @@
-global using Microsoft.VisualStudio.TestTools.UnitTesting;
+global using Microsoft.VisualStudio.TestTools.UnitTesting;

tests/indicators/s-z/Sma/Sma.StaticSeries.Tests.cs

@@ -1,7 +1,7 @@
 namespace StaticSeries;
 
 [TestClass]
-public class Sma : StaticSeriesTestBase
+public partial class Sma : StaticSeriesTestBase
 {
     [TestMethod]
     public override void Standard()

tests/indicators/s-z/Sma/Sma.Utilities.Tests.cs

@@ -0,0 +1,23 @@
+namespace StaticSeries;
+
+public partial class Sma : StaticSeriesTestBase
+{
+    [TestMethod]
+    public void Average()
+    {
+        QuotePart[] results = new[]
+        {
+            new QuotePart(Quotes[0].Timestamp, 0.0),
+            new QuotePart(Quotes[1].Timestamp, 4.0),
+            new QuotePart(Quotes[2].Timestamp, 8.0)
+        };
+
+        // sut
+        double? mid = results.Average(2, 1);
+        double? end = results.Average(2);
+
+        // assert
+        mid.Should().Be(2);
+        end.Should().Be(6);
+    }
+}