Simplify setup of a SQL database for unit tests

Using the LocalDb NuGet package makes it very easy to setup a test database. With the connection string from the App.config file I would get an exception:
> System.Data.SqlClient.SqlException
> A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 50 - Local Database Runtime error occurred. Cannot create an automatic instance. See the Windows Application event log for error details.)

test/Dapper.NodaTime.Tests/Dapper.NodaTime.Tests.csproj

@@ -9,25 +9,13 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="LocalDb" Version="10.7.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.3.0" />
+    <PackageReference Include="xunit.assemblyfixture" Version="2.0.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.3.1" />
     <PackageReference Include="xunit" Version="2.3.1" />
     <PackageReference Include="Dapper" Version="1.50.2" />
     <PackageReference Include="NodaTime" Version="2.2.2" />
   </ItemGroup>
 
-  <ItemGroup>
-    <Content Include="TestDB.mdf">
-      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
-    </Content>
-    <Content Include="TestDB_log.ldf">
-      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
-      <DependentUpon>TestDB.mdf</DependentUpon>
-    </Content>
-  </ItemGroup>
-
-  <ItemGroup>
-    <Reference Include="System.Configuration" />
-  </ItemGroup>
-
 </Project>

test/Dapper.NodaTime.Tests/DatabaseFixture.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Threading.Tasks;
+using LocalDb;
+
+namespace Dapper.NodaTime.Tests
+{
+    public class DatabaseFixture : IDisposable
+    {
+        private readonly SqlInstance _sqlInstance;
+        private readonly SqlDatabase _database;
+
+        public DatabaseFixture()
+        {
+            _sqlInstance = new SqlInstance(name: "Dapper.NodaTime.Tests", buildTemplate: _ => Task.CompletedTask);
+            _database = _sqlInstance.Build("DapperNodaTimeTests").Result;
+        }
+
+        public void Dispose()
+        {
+            _database.Dispose();
+            _sqlInstance.Cleanup();
+        }
+
+        public string ConnectionString => _database.ConnectionString;
+    }
+}

test/Dapper.NodaTime.Tests/InstantTests.cs

@@ -1,13 +1,12 @@
-using System.Configuration;
-using System.Data.SqlClient;
+using System.Data.SqlClient;
 using System.Linq;
 using NodaTime;
 using Xunit;
 
 namespace Dapper.NodaTime.Tests
 {
     [Collection("DBTests")]
-    public class InstantTests
+    public class InstantTests : IAssemblyFixture<DatabaseFixture>
     {
         private readonly string _connectionString;
 
@@ -16,9 +15,9 @@ private class TestObject
             public Instant? Value { get; set; }
         }
 
-        public InstantTests()
+        public InstantTests(DatabaseFixture databaseFixture)
         {
-            _connectionString = ConfigurationManager.ConnectionStrings["TestDB"].ConnectionString;
+            _connectionString = databaseFixture.ConnectionString;
             SqlMapper.AddTypeHandler(InstantHandler.Default);
         }
 

test/Dapper.NodaTime.Tests/LocalDateTests.cs

@@ -1,13 +1,12 @@
-using System.Configuration;
-using System.Data.SqlClient;
+using System.Data.SqlClient;
 using System.Linq;
 using NodaTime;
 using Xunit;
 
 namespace Dapper.NodaTime.Tests
 {
     [Collection("DBTests")]
-    public class LocalDateTests
+    public class LocalDateTests : IAssemblyFixture<DatabaseFixture>
     {
         private readonly string _connectionString;
 
@@ -16,9 +15,9 @@ private class TestObject
             public LocalDate? Value { get; set; }
         }
 
-        public LocalDateTests()
+        public LocalDateTests(DatabaseFixture databaseFixture)
         {
-            _connectionString = ConfigurationManager.ConnectionStrings["TestDB"].ConnectionString;
+            _connectionString = databaseFixture.ConnectionString;
             SqlMapper.AddTypeHandler(LocalDateHandler.Default);
         }
 

test/Dapper.NodaTime.Tests/LocalDateTimeTests.cs

@@ -1,13 +1,12 @@
-using System.Configuration;
-using System.Data.SqlClient;
+using System.Data.SqlClient;
 using System.Linq;
 using NodaTime;
 using Xunit;
 
 namespace Dapper.NodaTime.Tests
 {
     [Collection("DBTests")]
-    public class LocalDateTimeTests
+    public class LocalDateTimeTests : IAssemblyFixture<DatabaseFixture>
     {
         private readonly string _connectionString;
 
@@ -16,9 +15,9 @@ private class TestObject
             public LocalDateTime? Value { get; set; }
         }
 
-        public LocalDateTimeTests()
+        public LocalDateTimeTests(DatabaseFixture databaseFixture)
         {
-            _connectionString = ConfigurationManager.ConnectionStrings["TestDB"].ConnectionString;
+            _connectionString = databaseFixture.ConnectionString;
             SqlMapper.AddTypeHandler(LocalDateTimeHandler.Default);
         }
 

test/Dapper.NodaTime.Tests/LocalTimeTests.cs

@@ -1,13 +1,12 @@
-using System.Configuration;
-using System.Data.SqlClient;
+using System.Data.SqlClient;
 using System.Linq;
 using NodaTime;
 using Xunit;
 
 namespace Dapper.NodaTime.Tests
 {
     [Collection("DBTests")]
-    public class LocalTimeTests
+    public class LocalTimeTests : IAssemblyFixture<DatabaseFixture>
     {
         private readonly string _connectionString;
 
@@ -16,9 +15,9 @@ private class TestObject
             public LocalTime? Value { get; set; }
         }
 
-        public LocalTimeTests()
+        public LocalTimeTests(DatabaseFixture databaseFixture)
         {
-            _connectionString = ConfigurationManager.ConnectionStrings["TestDB"].ConnectionString;
+            _connectionString = databaseFixture.ConnectionString;
             SqlMapper.AddTypeHandler(LocalTimeHandler.Default);
         }
 

test/Dapper.NodaTime.Tests/OffsetDateTimeTests.cs

@@ -1,13 +1,12 @@
-using System.Configuration;
-using System.Data.SqlClient;
+using System.Data.SqlClient;
 using System.Linq;
 using NodaTime;
 using Xunit;
 
 namespace Dapper.NodaTime.Tests
 {
     [Collection("DBTests")]
-    public class OffsetDateTimeTests
+    public class OffsetDateTimeTests : IAssemblyFixture<DatabaseFixture>
     {
         private readonly string _connectionString;
 
@@ -16,9 +15,9 @@ public class TestObject
             public OffsetDateTime? Value { get; set; }
         }
 
-        public OffsetDateTimeTests()
+        public OffsetDateTimeTests(DatabaseFixture databaseFixture)
         {
-            _connectionString = ConfigurationManager.ConnectionStrings["TestDB"].ConnectionString;
+            _connectionString = databaseFixture.ConnectionString;
             SqlMapper.AddTypeHandler(OffsetDateTimeHandler.Default);
         }