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Backend Testing

OrganizationPopular
exceptionless
backend-testing

Write Exceptionless C# tests using local fixtures, HTTP helpers, and controlled time.

Overview

Publisherexceptionless
RepositoryExceptionless
Skill namebackend-testing
Stars
2.5K
Forks
508
Bundled files
Instructions only
LicenseApache-2.0
Links
  • Markdown instructions

    A SKILL.md file the model loads on demand, so it only costs tokens when a request actually matches.

  • Works with any LLM

    AI skills are plain Markdown, not provider-specific code, so this works with GPT, Claude, Gemini, Grok, or a local model.

  • Self-contained

    Everything the model needs lives in the instructions — no extra files to sync.

  • Open source

    Published by exceptionless on GitHub. Read the source before you install it.

Installation

Install the Backend Testing AI skill in TypingMind to use it with any LLM, or drop it into another agent that reads SKILL.md.

1

Install in TypingMind

TypingMind installs a skill straight from its GitHub folder — it reads SKILL.md, bundles the resource files, and stores the result locally.

  1. Open the app and go to Plugins → Skills.
  2. Choose "Install from GitHub".
  3. Paste the skill folder URL below and confirm.
    https://github.com/exceptionless/Exceptionless/tree/main/.agents/skills/backend-testing
  4. Enable the skill in any chat where you want it available.
Plugins → Skills → Add skill → From GitHub URL, then paste the folder URL and press Continue.
2

Install in another agent

Any agent that reads the Agent Skills format can use this skill — copy the folder into that agent's skills directory.

Claude Code — .claude/skills
git clone --depth 1 https://github.com/exceptionless/Exceptionless.git /tmp/Exceptionless
mkdir -p .claude/skills
cp -r /tmp/Exceptionless/.agents/skills/backend-testing .claude/skills/backend-testing
Restart Claude Code after copying so it picks up the new skill.

Use it in TypingMind

Enable Backend Testing in any TypingMind chat and the model takes it from there. Its name and description sit in the system prompt, and the moment a request matches, the model loads the full instructions itself — you never invoke it by hand, and it costs no tokens until it is actually used.

The model loads Backend Testing on its own as soon as a request matches it.

Works with any AI model

AI skills are plain Markdown instructions rather than provider-specific code, so Backend Testing is not tied to the model it was written for. Install it once in TypingMind and use it with GPT-5, Claude, Gemini, Grok, DeepSeek, Mistral, Llama, or a local model you run yourself — all on your own API keys.

  • Loaded only when it is needed

    The system prompt carries just the name and description. The instructions are fetched on the first matching request, so an idle skill costs nothing.

  • Switch models mid-chat

    Because the skill is instructions rather than code, changing model does not break it — the next model reads the same SKILL.md.

Skill instructions

This is the SKILL.md content the model loads. Read it before installing — a skill is instructions your model will follow.

Backend Testing

Unit test structure

Follow Microsoft's .NET unit testing best practices.

Organize tests as Arrange–Act–Assert:

  • Arrange: create the subject, minimal input, and required dependencies.
  • Act: perform the behavior under test, awaiting asynchronous work.
  • Assert: check the observable result and relevant side effects. Keep assertions separate from the action.

Keep unit tests fast, isolated, repeatable, and self-checking. Use clear names and minimal setup; test behavior rather than implementation details. Avoid branching or recreating production logic to calculate expected results. Before adding a test, identify the distinct regression it catches and inspect existing coverage. Extend an existing scenario or parameterize equivalent cases instead of duplicating setup. Combine assertions for the same behavior when they share expensive setup, while keeping independent behaviors separately diagnosable. Do not add trivial accessor, framework, or implementation-mirroring tests. Infrastructure-dependent checks belong in integration tests, using the fixtures below. Coverage percentages and test counts alone do not establish test quality.

Use the smallest fixture that proves the behavior. For batching/pagination, cross the real boundary rather than generating arbitrary thousands of records. Keep benchmarks out of the correctness suite. Inspect CI timing reports for expensive tests and preserve automatic shard discovery when restructuring test classes.

Fixtures and locations

Under tests/Exceptionless.Tests/:

  • IntegrationTestsBase.cs and AppWebHostFactory.cs: HTTP/service integration fixtures.
  • TestWithServices.cs: tests needing dependency injection.
  • Api/Endpoints/, Api/Filters/, Api/Handlers/, and Api/Results/: API tests by boundary.
  • Utility/AppSendBuilder.cs: fluent HTTP requests and assertions.
  • Utility/DataBuilder.cs: synthetic records.
  • Utility/ProxyTimeProvider.cs: controlled time.

Name tests MethodUnderTest_Scenario_ExpectedBehavior.

HTTP and state

Use SendRequestAsync with AppSendBuilder and its authorization helpers: AsGlobalAdminUser, AsTestOrganizationUser, AsFreeOrganizationUser, and AsTestOrganizationClientUser. Match an existing endpoint test for the expected response and fixture setup.

Use CreateDataAsync for synthetic data and RefreshDataAsync after database writes when reads require index refresh. ResetDataAsync clears the integration fixture's data; never point these fixtures at production.

Tests use the production serializer. For JSON compatibility, inspect Serializer/ and the relevant API snapshots.

Time

Use the fixture's TimeProvider: Advance, SetUtcNow, and Restore. Prefer controlled time to real waits.

Follow root guidance for focused commands, conditional Aspire startup, and API contract verification.

Frequently asked questions

What does the Backend Testing AI skill do?

Write Exceptionless C# tests using local fixtures, HTTP helpers, and controlled time.

Why use Backend Testing on TypingMind?

Because you install it once and use it with any model. Backend Testing is plain Markdown rather than provider-specific code, so the same skill runs on GPT-5, Claude, Gemini, Grok, or a local model — and you can switch model mid-chat without it breaking. TypingMind runs on your own API keys, so you pay providers directly instead of a per-seat subscription, and your skills and chats stay in your own storage.

How do I install Backend Testing in TypingMind?

Open Plugins → Skills → Install from GitHub in TypingMind and paste https://github.com/exceptionless/Exceptionless/tree/main/.agents/skills/backend-testing. TypingMind reads its SKILL.md and installs it as a skill you can enable per chat.

Which AI models can use Backend Testing?

Any model you connect in TypingMind. AI skills are plain Markdown instructions rather than provider-specific code, so GPT, Claude, Gemini, Grok, and local models can all load this skill when a request matches it.

How many AI models can I use with Backend Testing?

As many as you like. As long as a model supports skills, you can use Backend Testing with it — GPT, Claude, Gemini, Grok, DeepSeek, Mistral, Llama and more — all on TypingMind with your own API keys.

Is the Backend Testing AI skill free?

Yes. It is published on GitHub by exceptionless under the Apache-2.0 license. You only pay your own AI provider for the tokens you use.

What are AI skills?

An AI skill is a reusable instruction bundle that teaches an AI model how to do one specific task. It follows the open Agent Skills format: a SKILL.md file with a name and description, plus any scripts, templates or reference files the model may need. The model reads the instructions only when your request matches the skill, so an installed skill costs nothing until it is used.

How are AI skills different from plugins or MCP servers?

A plugin or MCP server gives a model new tools to call — code that runs somewhere and returns a result. An AI skill gives the model knowledge and process instead: how to approach a task, which steps to follow, what good output looks like. Skills are plain Markdown, so they need no server, no API key and no runtime, and they work with any model.

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