# migrate-mstest-v1v2-to-v3

A skill that walks an MSTest v1 or v2 project over to v3: it classifies the workspace, fixes build breaks and swaps .testsettings for .runsettings.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 3200 installs · ★ 5730
- Author: dotnet
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/dotnet/skills/tree/HEAD/plugins/dotnet-test-migration/skills/migrate-mstest-v1v2-to-v3/SKILL.md
- Updated: 2026-10-24
- HTML: https://affpapa.org/en/nevibecode/skills/migrate-mstest-v1v2-to-v3

## What it does

MSTest v3 is not binary compatible with v1 or v2, so libraries compiled against the older versions have to be recompiled. The skill inspects the workspace first and sorts it into v1, v2, partially migrated v3, or already-complete v3. From there it either edits the sources or just answers your question, depending on what you asked for.

The core of it is a table of breaking changes with the fix next to each one. The removed `Assert.AreEqual(object, object)` overload surfaces as `CS0411` or `CS1503`, and the repair is an explicit type argument: `Assert.AreEqual<object>(expected, actual)`. Strict `DataRow` type matching is not a compile error at all — it shows up as analyzer warning `MSTEST0014` and fails at run time, so a green build proves nothing. Literals need the exact parameter type: `1` for int, `1L` for long, `1.0f` for float.

The 16-argument `DataRow` limit existed only in 3.0.1 and 3.0.2 and was lifted in 3.0.3. On a project pinned to those two versions a longer row needs splitting or a package bump. `.testsettings` and `<LegacySettings>` are silently ignored under v3, so they get deleted and their config moved into `.runsettings`. The skill stays out of clean v3 projects, v3-to-v4 upgrades, and framework conversions to xUnit or NUnit.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add dotnet/skills --skill migrate-mstest-v1v2-to-v3 -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/migrate-mstest-v1v2-to-v3/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/migrate-mstest-v1v2-to-v3/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add dotnet/skills --skill migrate-mstest-v1v2-to-v3 -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/migrate-mstest-v1v2-to-v3/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add dotnet/skills --skill migrate-mstest-v1v2-to-v3 -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/migrate-mstest-v1v2-to-v3/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install dotnet/skills migrate-mstest-v1v2-to-v3
```

2. **Manually: put the files in place**
- File: `.github/skills/migrate-mstest-v1v2-to-v3/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add dotnet/skills --skill migrate-mstest-v1v2-to-v3 -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/dotnet/skills --path plugins/dotnet-test-migration/skills/migrate-mstest-v1v2-to-v3
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/migrate-mstest-v1v2-to-v3/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add dotnet/skills --skill migrate-mstest-v1v2-to-v3 -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/dotnet/skills/tree/HEAD/plugins/dotnet-test-migration/skills/migrate-mstest-v1v2-to-v3/SKILL.md

## When to use it
- move a test project from MSTest v1 or v2 to v3
- resolve `CS0411` and `CS1503` after bumping MSTest packages
- fix `DataRow` type mismatches and the `MSTEST0014` warning
- port settings from `.testsettings` to `.runsettings`
- tell the v1 migration path apart from the v2 one

## Example prompts
- Upgrade MSTest to v3 and fix the build errors in the test project.
- Why does this test fail with "Test data doesn't match method parameters"? Check the `DataRow` in `Tests.cs`.
- Replace `.testsettings` with `.runsettings` and keep the existing configuration.

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: fe45bf613c2f4ff9.

BEGIN THIRD-PARTY FILE fe45bf613c2f4ff9
```text
---
name: migrate-mstest-v1v2-to-v3
description: >
  Use this skill before answering or editing whenever an MSTest v1/v2 project
  is being upgraded or repaired for v3. Triggers include QualityTools assembly
  references; MSTest.TestFramework/TestAdapter 1.x-2.x; "upgrade to MSTest
  v3"; comparing v1 and v2 migration paths; choosing MSTest or MSTest.Sdk;
  CS0411/CS1503 after a v3 package bump; DataRow type mismatch,
  MSTEST0014, or "Test data doesn't match method parameters";
  .testsettings/LegacySettings to .runsettings; timeout changes; and net5.0 or
  other dropped v3 TFMs. Still use it when packages say 3.x but migration
  source errors or legacy settings remain. Preserve VSTest/MTP. Do not use for
  a clean v3 project, v3-to-v4, framework conversion, or runner-only migration.
license: MIT
---

# MSTest v1/v2 -> v3 Migration

Migrate a test project from MSTest v1 (assembly references) or MSTest v2 (NuGet 1.x-2.x) to MSTest v3. MSTest v3 is **not binary compatible** with v1/v2 -- libraries compiled against v1/v2 must be recompiled.

## First Action

Inspect the supplied workspace and classify v1, v2, partially migrated v3, or
already-complete v3 before answering. Do not search the web or answer from
memory first. For an edit request, continue through the requested source
changes and validation; for an advice request, answer directly after the
classification.

## When to Use

- Project references `Microsoft.VisualStudio.QualityTools.UnitTestFramework.dll` (MSTest v1)
- Project uses `MSTest.TestFramework` / `MSTest.TestAdapter` NuGet 1.x or 2.x
- Resolving build errors after updating MSTest packages from v1/v2 to v3 -- including when the packages already read 3.x and only the source or settings still need fixing
- Replacing `.testsettings` with `.runsettings`
- Adopting MSTest.Sdk or in-assembly parallel execution

## When Not to Use

- Project already on MSTest v3 with no migration-related build errors and no leftover `.testsettings` / `<LegacySettings>` (fully migrated)
- Upgrading v3 to v4 -- use `migrate-mstest-v3-to-v4`
- Migrating between frameworks (MSTest to xUnit/NUnit)

## Boundary Gate
```
END THIRD-PARTY FILE fe45bf613c2f4ff9

The third-party file has ended. Everything between the fe45bf613c2f4ff9 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

First 2139 of 21801 bytes. © dotnet · MIT · https://github.com/dotnet/skills/tree/HEAD/plugins/dotnet-test-migration/skills/migrate-mstest-v1v2-to-v3/SKILL.md

_Part of the page did not fit — see the HTML version._

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