feat(db): add SourceNode column to SiteCalls

tests/ScadaLink.ConfigurationDatabase.Tests/Migrations/AddSiteCallSourceNodeMigrationTests.cs

@@ -0,0 +1,75 @@
+using Xunit;
+
+namespace ScadaLink.ConfigurationDatabase.Tests.Migrations;
+
+/// <summary>
+/// SourceNode-stamping (#23) integration tests for the
+/// <c>AddSiteCallSourceNode</c> migration: applies the EF migrations to a
+/// freshly-created MSSQL test database on the running infra/mssql container and
+/// asserts that the central <c>SiteCalls</c> table carries the new
+/// <c>SourceNode varchar(64) NULL</c> column. No index — Site Call Audit KPIs
+/// are per-site, not per-node, on this table; <c>SourceNode</c> is operational
+/// metadata, not a query predicate here.
+/// </summary>
+/// <remarks>
+/// <c>SiteCalls</c> is non-partitioned (operational state, not audit), so this
+/// is a plain metadata-only <c>ALTER TABLE … ADD</c> with no index.
+/// </remarks>
+public class AddSiteCallSourceNodeMigrationTests : IClassFixture<MsSqlMigrationFixture>
+{
+    private readonly MsSqlMigrationFixture _fixture;
+
+    public AddSiteCallSourceNodeMigrationTests(MsSqlMigrationFixture fixture)
+    {
+        _fixture = fixture;
+    }
+
+    [SkippableFact]
+    public async Task AppliesMigration_AddsSourceNodeColumn_ToSiteCalls()
+    {
+        Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+        var present = await ScalarAsync<int>(
+            "SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS " +
+            "WHERE TABLE_NAME = 'SiteCalls' AND COLUMN_NAME = 'SourceNode' " +
+            "AND TABLE_SCHEMA = 'dbo';");
+        Assert.Equal(1, present);
+    }
+
+    [SkippableFact]
+    public async Task SourceNodeColumn_IsNullableVarchar64()
+    {
+        Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+        // varchar(64), not nvarchar — SourceNode is ASCII (`node-a`, `central-a` etc.).
+        var dataType = await ScalarAsync<string?>(
+            "SELECT DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS " +
+            "WHERE TABLE_NAME = 'SiteCalls' AND COLUMN_NAME = 'SourceNode';");
+        Assert.Equal("varchar", dataType);
+
+        var maxLength = await ScalarAsync<int>(
+            "SELECT CHARACTER_MAXIMUM_LENGTH FROM INFORMATION_SCHEMA.COLUMNS " +
+            "WHERE TABLE_NAME = 'SiteCalls' AND COLUMN_NAME = 'SourceNode';");
+        Assert.Equal(64, maxLength);
+
+        var isNullable = await ScalarAsync<string?>(
+            "SELECT IS_NULLABLE FROM INFORMATION_SCHEMA.COLUMNS " +
+            "WHERE TABLE_NAME = 'SiteCalls' AND COLUMN_NAME = 'SourceNode';");
+        Assert.Equal("YES", isNullable);
+    }
+
+    // --- helpers ------------------------------------------------------------
+
+    private async Task<T> ScalarAsync<T>(string sql)
+    {
+        await using var conn = _fixture.OpenConnection();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = sql;
+        var result = await cmd.ExecuteScalarAsync();
+        if (result is null || result is DBNull)
+        {
+            return default!;
+        }
+        return (T)Convert.ChangeType(result, typeof(T) == typeof(string) ? typeof(string) : Nullable.GetUnderlyingType(typeof(T)) ?? typeof(T))!;
+    }
+}