fix(db): repair fresh migration chain

JobTrackerApi.Tests/MigrationChainTests.cs

@@ -0,0 +1,119 @@
+using System.Data;
+using System.Text.RegularExpressions;
+using JobTrackerApi.Data;
+using JobTrackerApi.Services;
+using Microsoft.Data.Sqlite;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Moq;
+using Xunit;
+
+namespace JobTrackerApi.Tests;
+
+public sealed class MigrationChainTests
+{
+    private const string SnapshotMigration = "20260711181039_SyncModelSnapshot";
+
+    [Fact]
+    public async Task Blank_sqlite_chain_reaches_latest_and_is_idempotent()
+    {
+        await using var connection = new SqliteConnection("Data Source=:memory:");
+        await connection.OpenAsync();
+        await using var db = Context(connection);
+
+        await db.Database.MigrateAsync();
+        await db.Database.MigrateAsync();
+
+        Assert.Empty(await db.Database.GetPendingMigrationsAsync());
+        Assert.Equal(3, await ScalarAsync<long>(connection, """
+            SELECT COUNT(*) FROM sqlite_master
+            WHERE type = 'table' AND name IN ('AspNetUsers', 'AiInteractions', 'AiUsageRecords');
+            """));
+        Assert.Equal(10, await ScalarAsync<long>(connection, """
+            SELECT COUNT(*) FROM pragma_table_info('JobApplications')
+            WHERE name IN ('OwnerUserId', 'ShortSummary', 'TailoredCvText', 'TailoredCvUpdatedAt',
+                'LastReminderEmailSentAt', 'RecruiterMessageDraft', 'SalaryMin', 'SalaryMax',
+                'SalaryCurrency', 'SalaryPeriod');
+            """));
+    }
+
+    [Fact]
+    public async Task Populated_pre_job_split_database_preserves_rows_through_latest()
+    {
+        await using var connection = new SqliteConnection("Data Source=:memory:");
+        await connection.OpenAsync();
+        await using var db = Context(connection);
+        var migrator = db.GetService<IMigrator>();
+        await migrator.MigrateAsync(SnapshotMigration);
+        await ExecuteAsync(connection, """
+            INSERT INTO Companies (Name) VALUES ('Migration fixture');
+            INSERT INTO JobApplications
+                (CompanyId, JobTitle, DateApplied, Status, ResponseReceived, OwnerUserId, ShortSummary)
+            VALUES
+                (1, 'Preserved role', '2026-07-01 09:30:00', 'Applied', 0, 'owner-1', 'Preserved summary');
+            """);
+
+        await migrator.MigrateAsync();
+
+        await using var command = connection.CreateCommand();
+        command.CommandText = """
+            SELECT JobTitle, DateApplied, SavedAt, OwnerUserId, ShortSummary
+            FROM JobApplications WHERE Id = 1;
+            """;
+        await using var reader = await command.ExecuteReaderAsync();
+        Assert.True(await reader.ReadAsync());
+        Assert.Equal("Preserved role", reader.GetString(0));
+        Assert.Equal(reader.GetString(1), reader.GetString(2));
+        Assert.Equal("owner-1", reader.GetString(3));
+        Assert.Equal("Preserved summary", reader.GetString(4));
+        Assert.False(await reader.ReadAsync());
+        Assert.Empty(await db.Database.GetPendingMigrationsAsync());
+    }
+
+    [Fact]
+    public async Task MariaDb_script_keeps_new_identifiers_and_bootstrap_types_provider_safe()
+    {
+        var currentUser = new Mock<ICurrentUserService>();
+        currentUser.SetupGet(service => service.UserId).Returns((string?)null);
+        var options = new DbContextOptionsBuilder<JobTrackerContext>()
+            .UseMySql(
+                "Server=127.0.0.1;Database=script_only;User=none;Password=none;",
+                new MariaDbServerVersion(new Version(11, 0, 0)))
+            .Options;
+        await using var db = new JobTrackerContext(options, currentUser.Object);
+
+        var script = db.GetService<IMigrator>().GenerateScript();
+
+        Assert.Contains("`OwnerUserId` varchar(255)", script, StringComparison.Ordinal);
+        Assert.Contains("CONSTRAINT `FK_AccountDeletionFiles_Request`", script, StringComparison.Ordinal);
+        Assert.Contains("CREATE TABLE IF NOT EXISTS `AspNetUsers`", script, StringComparison.Ordinal);
+        Assert.Contains("CREATE TABLE IF NOT EXISTS `AiInteractions`", script, StringComparison.Ordinal);
+        Assert.All(
+            Regex.Matches(script, "CONSTRAINT `([^`]+)`").Select(match => match.Groups[1].Value),
+            identifier => Assert.True(identifier.Length <= 64, $"MariaDB constraint identifier exceeds 64 characters: {identifier}"));
+    }
+
+    private static JobTrackerContext Context(SqliteConnection connection)
+    {
+        var currentUser = new Mock<ICurrentUserService>();
+        currentUser.SetupGet(service => service.UserId).Returns((string?)null);
+        return new JobTrackerContext(
+            new DbContextOptionsBuilder<JobTrackerContext>().UseSqlite(connection).Options,
+            currentUser.Object);
+    }
+
+    private static async Task<T> ScalarAsync<T>(SqliteConnection connection, string sql)
+    {
+        await using var command = connection.CreateCommand();
+        command.CommandText = sql;
+        return (T)Convert.ChangeType(await command.ExecuteScalarAsync() ?? throw new DataException(), typeof(T));
+    }
+
+    private static async Task ExecuteAsync(SqliteConnection connection, string sql)
+    {
+        await using var command = connection.CreateCommand();
+        command.CommandText = sql;
+        await command.ExecuteNonQueryAsync();
+    }
+}