diff --git a/StoneAge.TestUtils.Tests/MockLoggerTests.cs b/StoneAge.TestUtils.Tests/MockLoggerTests.cs
new file mode 100644
index 0000000..4ceda1c
--- /dev/null
+++ b/StoneAge.TestUtils.Tests/MockLoggerTests.cs
@@ -0,0 +1,46 @@
+using System;
+using System.Linq;
+using Microsoft.Extensions.Logging;
+using StoneAge.TestUtils;
+using Xunit;
+
+namespace StoneAge.TestUtils.Tests
+{
+    public class MockLoggerTests
+    {
+        [Fact]
+        public void Log_AddsEntry_ForGivenLogLevel()
+        {
+            var logger = new MockLogger<string>();
+            logger.Log(LogLevel.Information, new EventId(), "Test message", null, (s, e) => s);
+
+            Assert.Contains("Test message", logger.LogEntries[LogLevel.Information]);
+        }
+
+        [Fact]
+        public void IsEnabled_AlwaysReturnsTrue()
+        {
+            var logger = new MockLogger<string>();
+            Assert.True(logger.IsEnabled(LogLevel.Debug));
+            Assert.True(logger.IsEnabled(LogLevel.Warning));
+        }
+
+        [Fact]
+        public void Fetch_Entries_For_ReturnsEntries()
+        {
+            var logger = new MockLogger<string>();
+            logger.Log(LogLevel.Error, new EventId(), "Error logged", null, (s, e) => s);
+
+            var entries = logger.Fetch_Entries_For(LogLevel.Error);
+            Assert.Single(entries);
+            Assert.Equal("Error logged", entries.First());
+        }
+
+        [Fact]
+        public void BeginScope_ThrowsNotImplementedException()
+        {
+            var logger = new MockLogger<string>();
+            Assert.Throws<NotImplementedException>(() => logger.BeginScope("scope"));
+        }
+    }
+}
\ No newline at end of file
diff --git a/StoneAge.TestUtils.Tests/MockOptionsSnapshotTests.cs b/StoneAge.TestUtils.Tests/MockOptionsSnapshotTests.cs
new file mode 100644
index 0000000..0094bd6
--- /dev/null
+++ b/StoneAge.TestUtils.Tests/MockOptionsSnapshotTests.cs
@@ -0,0 +1,33 @@
+using System;
+using StoneAge.TestUtils;
+using Xunit;
+
+namespace StoneAge.TestUtils.Tests
+{
+    public class MockOptionsSnapshotTests
+    {
+        private class Config
+        {
+            public int Value { get; set; }
+        }
+
+        [Fact]
+        public void Value_ReturnsInjectedInstance()
+        {
+            var config = new Config { Value = 123 };
+            var snapshot = new MockOptionsSnapshot<Config>(config);
+
+            Assert.Equal(123, snapshot.Value.Value);
+            Assert.Same(config, snapshot.Value);
+        }
+
+        [Fact]
+        public void Get_ThrowsNotImplementedException()
+        {
+            var config = new Config();
+            var snapshot = new MockOptionsSnapshot<Config>(config);
+
+            Assert.Throws<NotImplementedException>(() => snapshot.Get("any"));
+        }
+    }
+}
\ No newline at end of file
diff --git a/StoneAge.TestUtils.Tests/MockOptionsTests.cs b/StoneAge.TestUtils.Tests/MockOptionsTests.cs
new file mode 100644
index 0000000..3bb7bc2
--- /dev/null
+++ b/StoneAge.TestUtils.Tests/MockOptionsTests.cs
@@ -0,0 +1,23 @@
+using StoneAge.TestUtils;
+using Xunit;
+
+namespace StoneAge.TestUtils.Tests
+{
+    public class MockOptionsTests
+    {
+        private class Settings
+        {
+            public string Name { get; set; }
+        }
+
+        [Fact]
+        public void Value_ReturnsInjectedInstance()
+        {
+            var settings = new Settings { Name = "Test" };
+            var options = new MockOptions<Settings>(settings);
+
+            Assert.Equal("Test", options.Value.Name);
+            Assert.Same(settings, options.Value);
+        }
+    }
+}
\ No newline at end of file
diff --git a/StoneAge.TestUtils.Tests/StoneAge.TestUtils.Tests.csproj b/StoneAge.TestUtils.Tests/StoneAge.TestUtils.Tests.csproj
new file mode 100644
index 0000000..bfba4dd
--- /dev/null
+++ b/StoneAge.TestUtils.Tests/StoneAge.TestUtils.Tests.csproj
@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.3" />
+    <PackageReference Include="xunit" Version="2.4.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\TestUtils\StoneAge.TestUtils.csproj" />
+  </ItemGroup>
+
+</Project>
\ No newline at end of file
diff --git a/StoneAge.TestUtils.Tests/TestHttpClientBuilderTests.cs b/StoneAge.TestUtils.Tests/TestHttpClientBuilderTests.cs
new file mode 100644
index 0000000..1fc47bc
--- /dev/null
+++ b/StoneAge.TestUtils.Tests/TestHttpClientBuilderTests.cs
@@ -0,0 +1,36 @@
+using System.Net.Http;
+using System.Threading.Tasks;
+using StoneAge.TestUtils;
+using Xunit;
+
+namespace StoneAge.TestUtils.Tests
+{
+    public class TestHttpClientBuilderTests
+    {
+        [Fact]
+        public async Task Create_ReturnsClient_ThatReturnsPayload()
+        {
+            var builder = new TestHttpClientBuilder().With_Payload("{\"foo\":\"bar\"}");
+            var (client, handler) = builder.Create();
+
+            var response = await client.GetAsync("http://test");
+            var content = await response.Content.ReadAsStringAsync();
+
+            Assert.Equal("{\"foo\":\"bar\"}", content);
+            Assert.NotNull(handler.RequestMessage);
+            Assert.Equal("http://test/", handler.RequestMessage.RequestUri.ToString());
+        }
+
+        [Fact]
+        public async Task Create_ReturnsClient_WithDefaultPayload()
+        {
+            var builder = new TestHttpClientBuilder();
+            var (client, handler) = builder.Create();
+
+            var response = await client.GetAsync("http://test");
+            var content = await response.Content.ReadAsStringAsync();
+
+            Assert.Equal("{}", content);
+        }
+    }
+}
\ No newline at end of file
diff --git a/StoneAge.TestUtils.Tests/TestHttpMessageHandlerTests.cs b/StoneAge.TestUtils.Tests/TestHttpMessageHandlerTests.cs
new file mode 100644
index 0000000..0c9bc85
--- /dev/null
+++ b/StoneAge.TestUtils.Tests/TestHttpMessageHandlerTests.cs
@@ -0,0 +1,54 @@
+using System.Net.Http;
+using System.Threading.Tasks;
+using StoneAge.TestUtils;
+using Xunit;
+
+namespace StoneAge.TestUtils.Tests
+{
+    public class TestHttpMessageHandlerTests
+    {
+        [Fact]
+        public async Task SendAsync_ReturnsSpecifiedPayloadsInOrder()
+        {
+            var handler = new TestHttpMessageHandler()
+                .With_Payload("first")
+                .With_Payload("second");
+
+            var client = new HttpClient(handler);
+
+            var resp1 = await client.GetAsync("http://one");
+            var resp2 = await client.GetAsync("http://two");
+
+            var content1 = await resp1.Content.ReadAsStringAsync();
+            var content2 = await resp2.Content.ReadAsStringAsync();
+
+            Assert.Equal("first", content1);
+            Assert.Equal("second", content2);
+        }
+
+        [Fact]
+        public async Task SendAsync_ReturnsDefaultPayload_WhenNoneSpecified()
+        {
+            var handler = new TestHttpMessageHandler();
+            var client = new HttpClient(handler);
+
+            var resp = await client.GetAsync("http://none");
+            var content = await resp.Content.ReadAsStringAsync();
+
+            Assert.Equal("{}", content);
+        }
+
+        [Fact]
+        public async Task SendAsync_Sets_RequestMessage()
+        {
+            var handler = new TestHttpMessageHandler().With_Payload("payload");
+            var client = new HttpClient(handler);
+
+            var req = new HttpRequestMessage(HttpMethod.Get, "http://foo");
+            await client.SendAsync(req);
+
+            Assert.NotNull(handler.RequestMessage);
+            Assert.Equal("http://foo/", handler.RequestMessage.RequestUri.ToString());
+        }
+    }
+}
\ No newline at end of file
diff --git a/TestUtils.sln b/TestUtils.sln
index a8125a3..c579abb 100644
--- a/TestUtils.sln
+++ b/TestUtils.sln
@@ -1,9 +1,11 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.0.29009.5
+# Visual Studio Version 17
+VisualStudioVersion = 17.6.33804.203
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "StoneAge.TestUtils", "TestUtils\StoneAge.TestUtils.csproj", "{5F82CAB0-84CF-43F2-8572-27A74D56DF20}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "StoneAge.TestUtils", "TestUtils\StoneAge.TestUtils.csproj", "{C1E0C5AA-8D84-4D5B-90A6-7B091938E6C5}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "StoneAge.TestUtils.Tests", "StoneAge.TestUtils.Tests\StoneAge.TestUtils.Tests.csproj", "{D9E0C5BB-8D84-4D5B-90A6-7B091938E6C9}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -11,11 +13,16 @@ Global
 		Release|Any CPU = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{5F82CAB0-84CF-43F2-8572-27A74D56DF20}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{5F82CAB0-84CF-43F2-8572-27A74D56DF20}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{5F82CAB0-84CF-43F2-8572-27A74D56DF20}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{5F82CAB0-84CF-43F2-8572-27A74D56DF20}.Release|Any CPU.Build.0 = Release|Any CPU
+		{C1E0C5AA-8D84-4D5B-90A6-7B091938E6C5}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{C1E0C5AA-8D84-4D5B-90A6-7B091938E6C5}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{C1E0C5AA-8D84-4D5B-90A6-7B091938E6C5}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{C1E0C5AA-8D84-4D5B-90A6-7B091938E6C5}.Release|Any CPU.Build.0 = Release|Any CPU
+		{D9E0C5BB-8D84-4D5B-90A6-7B091938E6C9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{D9E0C5BB-8D84-4D5B-90A6-7B091938E6C9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D9E0C5BB-8D84-4D5B-90A6-7B091938E6C9}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{D9E0C5BB-8D84-4D5B-90A6-7B091938E6C9}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
+EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection