#tooling
tooling

Comparing two million-object lists for regression testing with Xero.DataComparer

Xero.DataComparer is a small, dependency-free .NET library for non-regression testing of pricing and risk engines. Instead of a boolean verdict, it reports which rows differ, on which properties, and which rows are missing on either side. The author says it compares two lists of one million objects in about 0.7 seconds, and explains the design choices behind that speed.

Tune GitHub Copilot Inline Suggestions with Configurable Eagerness

GitHub Copilot in VS Code now offers a configurable eagerness setting that controls how often inline suggestions appear and how large they are. Low, medium, and high modes all run on one model, selected with a control tag. The setting is available to paid Copilot subscribers, so you can match the assistance level to your task.

Mockly: fluent HTTP mocking for .NET tests that call HttpClient

Dennis Doomen released Mockly, an open-source library that makes testing code which calls HttpClient much simpler. It replaces hand-written HttpMessageHandler subclasses and fragile Moq setups on the protected SendAsync method. Its main strength is that failure paths such as retries, timeouts, 401 refreshes and 429 throttling can be simulated in a line or two, and unmatched requests produce a clear explanation.

Three Release Contracts for Obfuscated .NET Assemblies

Obfuscation turns into a release-engineering problem once you must rebuild, verify, or debug what shipped. The article proposes three contracts for Opaquer-protected releases: identity, integrity, and diagnostics. It gives .NET teams a practical checklist for keeping protected builds traceable and readable in production.

How to Review Claude-Generated .NET Tests for Real Regression Coverage

Claude-generated .NET tests can look complete and still miss the regression they are meant to catch. The author walks through tracing assertions back to their inputs, checking mock boundaries, and verifying that a test fails for the intended reason. It is a practical review checklist for anyone accepting agent-written tests into a C# codebase.

Where a .NET 8 repo hides its version before the November 10 end of support

.NET 8 and .NET 9 both leave support on November 10, 2026, and the in-process model for Azure Functions ends the same day. The author argues that the target framework is rarely a one-line change, because version pins hide in Directory.Build.props, global.json, Dockerfiles, CI workflows and Functions setup.

EF Core 11 adds .config/dotnet-ef.json for dotnet ef defaults

EF Core 11 lets the dotnet ef command-line tool read default options from a .config/dotnet-ef.json file. When your DbContext lives outside the startup project, you no longer need to repeat --project and --startup-project on every migration or database command. The tool finds the nearest config by walking up the folder tree, and explicit command-line flags still take precedence.

Marten 9.52.0 adds projection start floors and exception transforms

Marten 9.52.0, the PostgreSQL-based document and event store for .NET, adds a new schema table, an exception transform option and several tenant removal fixes. Anyone upgrading should know how the schema migration affects their databases before deploying.

Avalonia security incident: CMS breach, packages and customer data unaffected

Avalonia reported that unauthorised access during the 22-23 October 2026 attack was limited to its marketing website CMS. The entry point was an administrator token accidentally embedded in browser-delivered JavaScript. All 39 attempts to publish to its NuGet feeds were rejected, and customers need not reset passwords or replace licence keys.

Testing Cosmos DB writes locally and in GitHub Actions with the emulator

The Azure Cosmos DB blog shows how to test a database-backed feature against the Azure Cosmos DB Emulator running in Docker, then run the same tests in GitHub Actions. The example is a Python demo app, but the pattern applies to any .NET service that talks to Cosmos DB. Each pull request update runs against a fresh emulator, so you can check that a write reached storage and changed the answer, not just that the HTTP call returned 200.

PostSharp 2027.0 advice parameter binding removes boxing and allocations from aspects

PostSharp 2027.0 makes advice parameter binding public: aspect advices receive typed parameters instead of a MethodExecutionArgs object. That removes per-call heap allocations, boxing and casts on hot paths. Bindings are checked at build time, so mismatches fail the build rather than production.

Codex 0.164.0 adds /presets, inline /model and MCP sign-in

Codex CLI 0.164.0 lets you save reusable prompts and slash commands in ten numbered /presets slots. The /model and /permissions commands now accept inline arguments to set the model, reasoning effort, speed or permission profile in one go. Enterprise MCP connections gained new sign-in options, including OAuth clients that need secrets.