diff --git a/Burr.Tests/Burr.Tests.csproj b/Burr.Tests/Burr.Tests.csproj
index 001a7fd9..b5762003 100644
--- a/Burr.Tests/Burr.Tests.csproj
+++ b/Burr.Tests/Burr.Tests.csproj
@@ -56,6 +56,7 @@
     <Compile Include="ApiObjectMapTests.cs" />
     <Compile Include="Helpers\EnsureTests.cs" />
     <Compile Include="Http\BuilderTests.cs" />
+    <Compile Include="Http\ConnectionTests.cs" />
     <Compile Include="Http\ResponseTests.cs" />
     <Compile Include="Http\RequestHandlerTests.cs" />
     <Compile Include="Http\RequestTests.cs" />
diff --git a/Burr.Tests/Http/ConnectionTests.cs b/Burr.Tests/Http/ConnectionTests.cs
new file mode 100644
index 00000000..2e91a992
--- /dev/null
+++ b/Burr.Tests/Http/ConnectionTests.cs
@@ -0,0 +1,98 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Burr.Http;
+using Xunit;
+using Xunit.Extensions;
+using FluentAssertions;
+using Moq;
+
+namespace Burr.Tests.Http
+{
+    public class ConnectionTests
+    {
+        const string ExampleUrl = "http://example.com";
+        static Uri ExampleUri = new Uri(ExampleUrl);
+
+        public class TheConstructor
+        {
+            [Fact]
+            public void ThrowsForBadArguments()
+            {
+                Assert.Throws<ArgumentNullException>(() => new Connection(null));
+            }
+
+            [Fact]
+            public void DefaultsToStandardImplementations()
+            {
+                var c = new Connection(ExampleUri);
+
+                c.Builder.Should().BeOfType<Builder>();
+            }
+
+            [Fact]
+            public void CanUseCustomBuilder()
+            {
+                var builder = new Mock<IBuilder>();
+                builder.Setup(x => x.Run(It.IsAny<IApplication>())).Returns(Mock.Of<IApplication>());
+                var c = new Connection(ExampleUri);
+
+                c.Builder = builder.Object;
+
+                c.App.Should().NotBeNull();
+                builder.Verify(x => x.Run(It.IsAny<IApplication>()));
+            }
+
+            [Fact]
+            public void CanUseCustomMiddlewareStack()
+            {
+                var app = new Mock<IApplication>();
+                var c = new Connection(ExampleUri);
+                
+                c.MiddlewareStack = builder => builder.Run(app.Object);
+
+                c.App.Should().NotBeNull();
+                c.App.Should().Be(app.Object);
+            }
+        }
+
+        public class TheGetAsyncMethod
+        {
+            [Fact]
+            public async Task RunsConfigureAppWithAppropriateEnv()
+            {
+                var app = new Mock<IApplication>();
+                app.Setup(x => x.Call(It.IsAny<Env<string>>())).Returns(Task.FromResult<IApplication>(app.Object));
+                var c = new Connection(ExampleUri);
+                c.MiddlewareStack = builder => builder.Run(app.Object);
+
+                var res = await c.GetAsync<string>("/endpoint");
+
+                app.Verify(p => p.Call(It.Is<Env<string>>(x =>
+                        x.Request.BaseAddress == ExampleUri &&
+                        x.Request.Method == "GET" &&
+                        x.Request.Endpoint == "/endpoint")), Times.Once());
+            }
+
+            [Fact]
+            public async Task CanMakeMutipleRequestsWithSameConnection()
+            {
+                var app = new Mock<IApplication>();
+                app.Setup(x => x.Call(It.IsAny<Env<string>>())).Returns(Task.FromResult<IApplication>(app.Object));
+                var c = new Connection(ExampleUri);
+                c.MiddlewareStack = builder => builder.Run(app.Object);
+
+                var res = await c.GetAsync<string>("/endpoint");
+                res = await c.GetAsync<string>("/endpoint");
+                res = await c.GetAsync<string>("/endpoint");
+
+                app.Verify(p => p.Call(It.Is<Env<string>>(x =>
+                        x.Request.BaseAddress == ExampleUri &&
+                        x.Request.Method == "GET" &&
+                        x.Request.Endpoint == "/endpoint")), Times.Exactly(3));
+            }
+        }
+    }
+}
diff --git a/Burr.Tests/Http/ResponseHandlerTests.cs b/Burr.Tests/Http/ResponseHandlerTests.cs
index dcd43db9..54eecf80 100644
--- a/Burr.Tests/Http/ResponseHandlerTests.cs
+++ b/Burr.Tests/Http/ResponseHandlerTests.cs
@@ -23,6 +23,7 @@ namespace Burr.Tests.Http
 
             protected override void Before<T>(Env<T> env)
             {
+                base.Before(env);
                 BeforeWasCalled = true;
             }
 
diff --git a/Burr/Http/Connection.cs b/Burr/Http/Connection.cs
index 06957c31..da992bc0 100644
--- a/Burr/Http/Connection.cs
+++ b/Burr/Http/Connection.cs
@@ -1,14 +1,19 @@
 using System;
 using System.Threading.Tasks;
+using Burr.Helpers;
 
 namespace Burr.Http
 {
     public class Connection : IConnection
     {
+        static readonly Func<IBuilder, IApplication> defaultStack = builder => { return builder.Run(new HttpClientAdapter()); };
+
         Uri baseAddress;
 
         public Connection(Uri baseAddress)
         {
+            Ensure.ArgumentNotNull(baseAddress, "baseAddress");
+
             this.baseAddress = baseAddress;
         }
 
@@ -57,7 +62,6 @@ namespace Burr.Http
             }
         }
 
-        static readonly Func<IBuilder, IApplication> defaultStack = builder => { return builder.Run(new HttpClientAdapter()); };
         Func<IBuilder, IApplication> middlewareStack;
         public Func<IBuilder, IApplication> MiddlewareStack
         {