Add integration tests

tests/WebApi.Tests.Integration/PostgresRespawner.cs

@@ -0,0 +1,40 @@
+using Npgsql;
+using Respawn;
+using System.Data.Common;
+
+namespace WebApi.Tests.Integration;
+internal sealed class PostgresRespawner : IDisposable
+{
+	private readonly DbConnection _connection;
+	private readonly Respawner _respawner;
+
+	private PostgresRespawner(Respawner respawner, DbConnection connection)
+	{
+		_respawner = respawner;
+		_connection = connection;
+	}
+
+	public static async Task<PostgresRespawner> CreateAsync(string connectionString)
+	{
+		DbConnection connection = new NpgsqlConnection(connectionString);
+		await connection.OpenAsync();
+
+		var respawner = await Respawner.CreateAsync(connection,
+			new RespawnerOptions
+			{
+				SchemasToInclude = ["public"],
+				DbAdapter = DbAdapter.Postgres
+			});
+		return new PostgresRespawner(respawner, connection);
+	}
+
+	public async Task ResetDatabaseAsync()
+	{
+		await _respawner.ResetAsync(_connection);
+	}
+
+	public void Dispose()
+	{
+		_connection.Dispose();
+	}
+}