Create common test infrastructure project

test/Common/AutoFixture/FixtureExtensions.cs

@@ -0,0 +1,11 @@
+using AutoFixture;
+using AutoFixture.AutoNSubstitute;
+
+namespace Bit.Test.Common.AutoFixture
+{
+    public static class FixtureExtensions
+    {
+        public static IFixture WithAutoNSubstitutions(this IFixture fixture)
+            => fixture.Customize(new AutoNSubstituteCustomization());
+    }
+}