Add pending migration test (#293)

Addresses NuGet/NuGetGallery#4934
Similar to NuGet/NuGetGallery#7143

tests/NuGet.Services.Validation.Tests/NuGet.Services.Validation.Tests.csproj

@@ -43,6 +43,7 @@
     <Compile Include="Entities\PackageSignatureTypeTests.cs" />
     <Compile Include="Entities\EndCertificateUseTests.cs" />
     <Compile Include="Entities\SymbolServerRequestTests.cs" />
+    <Compile Include="PendingMigrationsTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ServiceBusMessageSerializerTests.cs" />
     <Compile Include="TestData.Designer.cs">

tests/NuGet.Services.Validation.Tests/PendingMigrationsTests.cs

@@ -0,0 +1,96 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Data.Entity.Infrastructure;
+using System.Data.Entity.Migrations;
+using System.Data.Entity.Migrations.Design;
+using System.Data.SqlClient;
+using System.Linq;
+using System.Threading.Tasks;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace NuGet.Services.Validation.Tests
+{
+    public class PendingMigrationsFacts : IAsyncLifetime
+    {
+        private string _dbName;
+        private readonly ITestOutputHelper _output;
+
+        public PendingMigrationsFacts(ITestOutputHelper output)
+        {
+            _output = output;
+        }
+
+        public Task InitializeAsync()
+        {
+            return Task.CompletedTask;
+        }
+
+        public async Task DisposeAsync()
+        {
+            if (_dbName == null)
+            {
+                return;
+            }
+
+            const string connectionString = @"Data Source=(localdb)\mssqllocaldb; Initial Catalog=master; Integrated Security=True; MultipleActiveResultSets=True";
+            using (var sqlConnection = new SqlConnection(connectionString))
+            {
+                await sqlConnection.OpenAsync();
+                using (var sqlCommand = sqlConnection.CreateCommand())
+                {
+                    sqlCommand.CommandText = $"ALTER DATABASE {_dbName} SET SINGLE_USER WITH ROLLBACK IMMEDIATE; DROP DATABASE {_dbName};";
+                    await sqlCommand.ExecuteNonQueryAsync();
+                }
+            }
+        }
+
+        [Fact]
+        public void NoPendingMigrations()
+        {
+            var currentTimestamp = DateTimeOffset.UtcNow.ToString("yyyyMMddHHmmssFFFFFFF");
+            _dbName = $"PendingMigrationsTest{currentTimestamp}Validation";
+            var connectionString = $@"Data Source=(localdb)\mssqllocaldb; Initial Catalog={_dbName}; Integrated Security=True; MultipleActiveResultSets=True";
+
+            var migrationsConfiguration = new ValidationMigrationsConfiguration
+            {
+                TargetDatabase = new DbConnectionInfo(connectionString, "System.Data.SqlClient"),
+            };
+
+            var dbMigrator = new DbMigrator(migrationsConfiguration);
+            var migrations = dbMigrator.GetLocalMigrations();
+            dbMigrator.Update(migrations.Last());
+
+            var migrationScaffolder = new MigrationScaffolder(dbMigrator.Configuration);
+
+            var migrationName = $"TestMigration{currentTimestamp}";
+            var result = migrationScaffolder.Scaffold(migrationName);
+
+            _output.WriteLine("Migration content:");
+            _output.WriteLine(new string('-', 60));
+            _output.WriteLine(result.UserCode);
+            _output.WriteLine(new string('-', 60));
+
+            Assert.Equal(
+                $@"namespace {dbMigrator.Configuration.MigrationsNamespace}
+{{
+    using System;
+    using System.Data.Entity.Migrations;
+    
+    public partial class {migrationName} : DbMigration
+    {{
+        public override void Up()
+        {{
+        }}
+        
+        public override void Down()
+        {{
+        }}
+    }}
+}}
+", result.UserCode);
+        }
+    }
+}