diff --git a/ExaArrayTests/ExaArray1DTests.cs b/ExaArrayTests/ExaArray1DTests.cs
index 5bd1f38..75ca7ca 100644
--- a/ExaArrayTests/ExaArray1DTests.cs
+++ b/ExaArrayTests/ExaArray1DTests.cs
@@ -1,7 +1,88 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using System.Threading.Tasks;
+using Exa;
+using NUnit.Framework;
+
 namespace ExaArrayTests
 {
     public class ExaArray1DTests
     {
-        
+        [ExcludeFromCodeCoverage]
+        public class InfinityArrayTests
+        {
+            [Test]
+            public void CreatingNormalSize01()
+            {
+                var exaA = new ExaArray1D<byte>();
+                Assert.That(exaA.Length, Is.EqualTo(0));
+                Assert.Throws<IndexOutOfRangeException>(() =>
+                {
+                    var n = exaA[0];
+                });
+                Assert.That(exaA.Items(), Is.Empty);
+
+                exaA.Extend();
+                Assert.That(exaA.Length, Is.EqualTo(1));
+                Assert.That(exaA.Items(), Is.EquivalentTo(new[] {0x00}));
+                Assert.That(exaA[0], Is.EqualTo(0));
+
+                exaA[0] = 0xFF;
+                Assert.That(exaA.Length, Is.EqualTo(1));
+                Assert.That(exaA.Items(), Is.EquivalentTo(new[] {0xFF}));
+                Assert.That(exaA[0], Is.EqualTo(0xFF));
+            }
+
+            [Test]
+            public void CreatingNormalSize02()
+            {
+                var exaA = new ExaArray1D<int>();
+                exaA.Extend(1_000_000);
+
+                Assert.That(exaA.Length, Is.EqualTo(1_000_000));
+                for (ulong n = 0; n < 1_000_000; n++)
+                {
+                    exaA[n] = (int) (n * n);
+                }
+
+                Assert.That(exaA.Items().Count(), Is.EqualTo(1_000_000));
+
+                exaA.Extend();
+                Assert.That(exaA.Length, Is.EqualTo(1_000_001));
+            }
+
+            [Test]
+            public void CountingHugeSize01()
+            {
+                var exaA = new ExaArray1D<byte>();
+                exaA.Extend(5_000_000_000);
+
+                Assert.That(exaA.Length, Is.EqualTo(5_000_000_000));
+                Assert.Throws<OverflowException>(() =>
+                {
+                    // Cannot work because linq uses int:
+                    var n = exaA.Items().Count();
+                });
+            }
+
+            [Test]
+            public void Adding5Billion01()
+            {
+                ulong sum1 = 0;
+                var exaA = new ExaArray1D<byte>();
+                exaA.Extend(5_000_000_000);
+
+                Assert.That(exaA.Length, Is.EqualTo(5_000_000_000));
+                for (ulong n = 0; n < 5_000_000_000; n++)
+                {
+                    exaA[n] = 1;
+                    sum1 += 1;
+                }
+
+                var sum2 = exaA.Items().Aggregate<byte, ulong>(0, (current, item) => current + item);
+                Assert.That(sum1, Is.EqualTo(sum2));
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/ExaArrayTests/ExaArrayTests.csproj b/ExaArrayTests/ExaArrayTests.csproj
index a3fa66f..e0221a6 100644
--- a/ExaArrayTests/ExaArrayTests.csproj
+++ b/ExaArrayTests/ExaArrayTests.csproj
@@ -12,4 +12,8 @@
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.4.0" />
     </ItemGroup>
 
+    <ItemGroup>
+      <ProjectReference Include="..\ExaArray\ExaArray.csproj" />
+    </ItemGroup>
+
 </Project>