Address PR #485 review feedback: Add unique index on ExternalId, comprehensive tests, and fix test name

[Copilot]

Addresses three review comments from PR #485 regarding the Markdown Import feature.

Changes

• Add unique filtered index on ExternalId: Index on BlogPost.ExternalId with WHERE ExternalId IS NOT NULL filter to improve import lookup performance while allowing multiple nulls. Prevents table scans and duplicate external IDs.

• Add MarkdownImportJobTests: 9 integration tests covering create/update paths, disabled feature behavior, error handling (invalid markdown, source provider failures, partial failures), and cache invalidation logic.

• Rename test: Should_Migrate_From_11_To_12 → Should_Migrate_To_Version_13 to reflect actual target version.

The unique index prevents the non-deterministic update behavior mentioned in the review when multiple posts share the same external ID:

builder.HasIndex(x => x.ExternalId)
    .HasDatabaseName("IX_BlogPosts_ExternalId")
    .IsUnique()
    .HasFilter("ExternalId IS NOT NULL");

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[Copilot]

Pull request overview

This pull request addresses review feedback from PR #485 by adding a unique filtered index on BlogPost.ExternalId, comprehensive integration tests for the Markdown Import feature, and fixing a test name to reflect the correct migration version.

Changes:

• Added unique filtered index on BlogPost.ExternalId with WHERE ExternalId IS NOT NULL to prevent duplicates and improve query performance
• Added 9 comprehensive integration tests for MarkdownImportJob covering create/update operations, error handling, and cache invalidation
• Renamed migration test from Should_Migrate_From_11_To_12 to Should_Migrate_To_Version_13 to accurately reflect the target version

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/LinkDotNet.Blog.UpgradeAssistant.Tests/MigrationManagerTests.cs	Renamed test method to accurately reflect migration to version 13
tests/LinkDotNet.Blog.IntegrationTests/Web/Features/MarkdownImportJobTests.cs	Added comprehensive test suite with 9 tests covering all major scenarios including create, update, error handling, and cache invalidation
src/LinkDotNet.Blog.Infrastructure/Persistence/Sql/Mapping/BlogPostConfiguration.cs	Added unique filtered index on ExternalId column for data integrity and performance
src/LinkDotNet.Blog.Infrastructure/Migrations/BlogDbContextModelSnapshot.cs	Updated model snapshot to reflect new ExternalId index
src/LinkDotNet.Blog.Infrastructure/Migrations/20260125214130_AddUniqueIndexOnExternalId.cs	Added migration to create unique filtered index on ExternalId
src/LinkDotNet.Blog.Infrastructure/Migrations/20260125214130_AddUniqueIndexOnExternalId.Designer.cs	Auto-generated designer file for the new migration

Files not reviewed (1)

• src/LinkDotNet.Blog.Infrastructure/Migrations/20260125214130_AddUniqueIndexOnExternalId.Designer.cs: Language not supported

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[Copilot]

The namespace for this migration file is inconsistent with other migration files in the same directory. All other migrations in the codebase use LinkDotNet.Blog.Web.Migrations as their namespace (see 20250830110439_AddAuthorNameInBlogPost.cs, 20260109211327_AddBlogPostTemplate.cs, and 20260125204524_AddExternalIdToBlogPost.cs), but this file uses LinkDotNet.Blog.Infrastructure.Migrations. This inconsistency could lead to confusion and potential issues with migration discovery. Please change the namespace to match the established convention.

[Copilot]

The namespace for this migration designer file is inconsistent with other migration files in the same directory. All other migrations in the codebase use LinkDotNet.Blog.Web.Migrations as their namespace, but this file uses LinkDotNet.Blog.Infrastructure.Migrations. This inconsistency could lead to confusion and potential issues with migration discovery. Please change the namespace to match the established convention.

[Copilot]

The tests in this file use TestContext.Current.CancellationToken while other similar job test files in the codebase use CancellationToken.None (see BlogPostPublisherTests.cs and SimilarBlogPostJobTests.cs). For consistency with the established pattern in the codebase, consider using CancellationToken.None instead of TestContext.Current.CancellationToken unless there's a specific reason for the different approach.