scaffold-dotnet-test-project

name	scaffold-dotnet-test-project
description	Create, reuse, register, or repair .NET test-project and CI discovery wiring. ALWAYS INVOKE to create/set up the first test project; add/register/include an existing test project in a .sln, .slnx, .slnf, solution filter, or CI; restore a missing/lost ProjectReference; or fix tests that pass directly while the solution/CI discovers zero tests. Handles xUnit/NUnit/MSTest and central packages. DO NOT USE to only author tests in an already-wired project (code-testing-agent), run tests, migrate, or correct MSTest syntax/configuration without changing project or CI files (writing-mstest-tests).
license	MIT

Scaffold or Repair a .NET Test Project

Create the smallest missing test container or repair only the missing wiring. The goal is test discovery through the repository's real build entry point, not a preferred solution layout.

Route the Request

Inspect the repository before editing, then choose exactly one path:

Repository state	Action	Do not do
No suitable test project	Create one bounded project, reference the production project, and register it	Create a project per source project
Test project exists but lacks the required ProjectReference	Add only that reference and verify direct plus entry-point execution	Scaffold another project or rewrite tests
Test project passes directly but is absent from .sln, .slnx, or .slnf	Register the existing project in the exact entry point CI uses	Recreate the project or switch solution formats
Suitable project, reference, and requested entry point are already correct	Leave the workspace unchanged; use code-testing-agent if test methods are requested	Normalize or replace working files

An existing project is suitable when its target framework can reference the production project and its purpose matches the requested layer. A different preferred name is not a reason to create a duplicate.

Workflow

1. Establish the repository contract

Start from the task's current working directory. The skill context's Base directory is where these instructions live, not the user's repository. Never search parent temporary directories or treat the skill installation as the workspace. If the expected files are not visible, confirm the current directory before concluding that a project is absent.

Anchor every edit and validation command to the repository path named by the user or established from the current directory. If similarly named fixtures, solutions, or copied trees exist, do not edit or validate one as a substitute for the requested tree. Before changing a solution artifact, record its exact path; after changing it, list that same artifact immediately and require the test project to appear before proceeding.

Read only enough to determine:

1. the production project and requested test scope;
2. the command and .sln, .slnx, .slnf, or project graph used by CI;
3. whether a suitable test project exists, what it references, and where it is registered;
4. the neighboring test framework, runner, target framework, nullable and implicit-usings conventions; and
5. whether package or SDK versions come from Directory.Packages.props, Directory.Build.props, global.json, or an MSBuild SDK declaration.

If the user reports that a test project passes directly but solution-level discovery finds nothing, treat that as registration evidence. Inspect the entry point before considering project creation.

2. Create only when the project is absent

Choose one test project for the narrowest requested production project. Follow, in order, the user's explicit framework choice, neighboring test projects, repository-wide package/SDK conventions, then a standard SDK template.

Use a dotnet new template only when its generated framework generation and package style match the repository contract. Inspect template availability before creation. In particular, generic dotnet new xunit commonly emits xUnit 2 packages; for a centrally managed xunit.v3 repository, use a repository or installed xUnit v3 template, or create the minimal SDK project directly. Never generate versioned xUnit 2 references and then rewrite them into xUnit v3.

Then:

1. align target framework, nullable, implicit usings, runner, and package style;
2. use dotnet add <test-project> reference <production-project> for only the production projects exercised by the requested tests;
3. delete template sample files such as UnitTest1.cs, then create a behavior-named test file rather than repurposing the template filename; and
4. omit package versions when central package management supplies them.

For xUnit v3 projects that run through dotnet test, preserve or add:

<OutputType>Exe</OutputType>
<TestingPlatformDotnetTestSupport>true</TestingPlatformDotnetTestSupport>

OutputType=Exe alone proves only the self-hosted runner path, not discovery by the repository's dotnet test command.

3. Repair only the missing edge when the project exists

• Missing production reference: use dotnet add <test-project> reference <production-project>, inspect the resulting project, and leave package and test source files unchanged.
• Missing .sln or .slnx registration: run dotnet sln <entry-point> add <test-project>, then immediately run dotnet sln <entry-point> list against that exact path. If the project is absent, the repair has not happened; do not validate a sibling solution or report success.
• Missing .slnf registration: add the existing project to its underlying solution if necessary, then include that same project path in the filter.
• Multiple solution artifacts: modify only the one named by the user or invoked by CI. Do not substitute an easier format.
• No solution artifact: preserve the existing project-oriented workflow. Do not create a solution for aesthetics.

4. Add only the requested smoke behavior

For a newly created project, replace template examples with the smallest smoke suite the user requested. Each test must invoke a real production symbol and assert a concrete deterministic result without network, wall-clock, process, or real-filesystem dependencies.

For an existing-project wiring repair, do not add, rewrite, rename, or expand tests unless the user explicitly asks for test behavior changes. Registration and test authoring are separate operations.

5. Verify the repaired path

Run the narrowest commands that prove the chosen route:

Route	Required evidence
Newly created project	dotnet test <test-project>, exact entry-point test/build command, and registration listing
Missing reference	Targeted project test plus the exact solution/root test command requested
Missing .sln/.slnx registration	Listing and dotnet test for that exact artifact; never use another solution as a fallback
Missing .slnf entry	Inspect the filter entry and run the exact CI filter build command; do not prepend a deliberately failing alternate command
Already correct/no-op	Structural inspection of the existing reference and registration. Unless execution was requested, do not run tests merely to prove a no-op because that creates bin/obj and weakens byte-for-byte cleanliness evidence.

Inspect the repository's command before adding switches. Do not prepend a speculative --no-restore attempt or hide alternatives in command-a || command-b; run the configured entry-point command whose clean exit is the evidence.

Before reporting completion, inspect the final changed-file set. Remove only bin/obj or equivalent build artifacts created by this task when they were absent beforehand and are not intentionally tracked; never remove pre-existing artifacts. Preserve the passing command's complete result so the handoff can state the exact entry point and discovered test count.

For a no-op, inspect rather than rewrite and report the existing paths. A green dotnet build is not test-discovery evidence. If validation is blocked, report the exact failing command and first actionable error; never describe an unrun or failed command as successful.

Output

Keep the handoff proportional to the change:

Requirement	Evidence
Project created, reused, or repaired	Test project path and chosen route
Production reference	Referenced .csproj, or why no change was needed
Build registration	Exact .sln/.slnx/.slnf entry or project workflow
Test discovery	Passing harness-level command and discovered test

Completion Checks

• Existing projects were checked before creation.
• Only the requested production scope is referenced and tested.
• Framework, runner, target framework, and central package conventions remain intact.
• Template samples are removed from a newly created project.
• Existing test code is untouched for a wiring-only repair.
• The exact repository entry point discovers and runs the test project.