diff --git a/tests/FilterLists.Services.Tests/Extensions/AddIfNotNullOrEmptyShould.cs b/tests/FilterLists.Services.Tests/Extensions/AddIfNotNullOrEmptyShould.cs
deleted file mode 100644
index b3a2fae3f..000000000
--- a/tests/FilterLists.Services.Tests/Extensions/AddIfNotNullOrEmptyShould.cs
+++ /dev/null
@@ -1,40 +0,0 @@
-using System.Collections.Generic;
-using System.Collections.ObjectModel;
-using FilterLists.Services.Extensions;
-using Xunit;
-
-namespace FilterLists.Services.Tests.Extensions
-{
-    public class AddIfNotNullOrEmptyShould
-    {
-        public AddIfNotNullOrEmptyShould() =>
-            sut = new Collection<string>();
-
-        private readonly ICollection<string> sut;
-        private string item;
-
-        [Fact]
-        public void AddIfNotNullOrEmpty()
-        {
-            item = "item";
-            sut.AddIfNotNullOrEmpty(item);
-            Assert.Contains(item, sut);
-        }
-
-        [Fact]
-        public void NotAddIfEmpty()
-        {
-            item = "";
-            sut.AddIfNotNullOrEmpty(item);
-            Assert.DoesNotContain(item, sut);
-        }
-
-        [Fact]
-        public void NotAddIfNull()
-        {
-            item = null;
-            sut.AddIfNotNullOrEmpty(item);
-            Assert.DoesNotContain(item, sut);
-        }
-    }
-}
\ No newline at end of file
diff --git a/tests/FilterLists.Services.Tests/Extensions/CollectionExtensionShould.cs b/tests/FilterLists.Services.Tests/Extensions/CollectionExtensionShould.cs
new file mode 100644
index 000000000..0b0befb8d
--- /dev/null
+++ b/tests/FilterLists.Services.Tests/Extensions/CollectionExtensionShould.cs
@@ -0,0 +1,66 @@
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using FilterLists.Services.Extensions;
+using Xunit;
+
+namespace FilterLists.Services.Tests.Extensions
+{
+    public abstract class CollectionExtensionShould
+    {
+        protected readonly ICollection<string> Sut;
+
+        protected CollectionExtensionShould() =>
+            Sut = new Collection<string>();
+    }
+
+    public class AddIfNotNullOrEmptyShould : CollectionExtensionShould
+    {
+        private string item;
+
+        [Fact]
+        public void AddIfNotNullOrEmpty()
+        {
+            item = "item";
+            Sut.AddIfNotNullOrEmpty(item);
+            Assert.Contains(item, Sut);
+        }
+
+        [Fact]
+        public void NotAddIfEmpty()
+        {
+            item = "";
+            Sut.AddIfNotNullOrEmpty(item);
+            Assert.DoesNotContain(item, Sut);
+        }
+
+        [Fact]
+        public void NotAddIfNull()
+        {
+            item = null;
+            Sut.AddIfNotNullOrEmpty(item);
+            Assert.DoesNotContain(item, Sut);
+        }
+    }
+
+    public class AddRangeShould : CollectionExtensionShould
+    {
+        private IEnumerable<string> range;
+
+        [Fact]
+        public void AddCollectionOfStrings()
+        {
+            range = new Collection<string> {"item1", "item2"};
+            Sut.AddRange(range);
+            Assert.True(!range.Except(Sut).Any());
+        }
+
+        [Fact]
+        public void AddListOfStrings()
+        {
+            range = new List<string> {"item1", "item2"};
+            Sut.AddRange(range);
+            Assert.True(!range.Except(Sut).Any());
+        }
+    }
+}
\ No newline at end of file