mcpbeat

Test Tagging

dotnet/test-tagging

Analyzes test suites in any language and tags each test with standardized traits (positive, negative, critical-path, boundary, smoke, regression, integration, performance, security). Use when the user wants to categorize, audit, or label tests with traits. Works across .NET (MSTest/xUnit/NUnit/TUnit), Python (pytest), TS/JS (Jest/Vitest), Java, Go, Ruby, Rust, Swift, Kotlin, PowerShell, and C++ — auto-editing when the framework has canonical tag syntax, otherwise report-only. Do not use for writing new tests, running tests, or migrating frameworks.

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Install

one command, takes just this skill from the repository
npx skills add https://github.com/dotnet/skills --skill test-tagging

The instruction itself

13 sections, as written by the author

Test Trait Tagging

Analyze an existing test suite in any supported language and apply a standardized set of trait tags to each test method, giving teams visibility into their test distribution (positive vs. negative, critical-path coverage, smoke tests, etc.).

> Language-specific guidance: Call the test-analysis-extensions skill to discover available extension files, then read the file matching the target codebase. The extension file documents framework-specific tag attributes and a "tag-support capability" (auto-edit, report-only, or convention-based) that drives whether this skill modifies source files or only emits a report.

When to Use

  • Auditing a test project to understand the mix of test types
  • Adding trait attributes to untagged tests
  • Generating a summary report of trait distribution across a test suite
  • Reviewing whether critical paths have sufficient coverage

When Not to Use

  • Writing new tests from scratch (use code-testing-agent for any language, or writing-mstest-tests for MSTest)
  • Running or filtering tests (use run-tests for .NET; equivalent native runners elsewhere)
  • Migrating between test frameworks

Inputs

| Input | Required | Description |

|-------|----------|-------------|

| Test project or files | Yes | Path to the test project, folder, or specific test files to analyze |

| Scope | No | tag (apply attributes when language supports auto-edit), audit (report only), or both (default: both). For languages with no canonical tag syntax, the skill emits a report regardless of scope. |

| Framework | No | Auto-detected. Override when detection fails. |

Trait Taxonomy

Use exactly these trait names and values. Do not invent new trait values outside this table.

| Trait Value | Meaning | Heuristics |

|-------------|---------|------------|

| positive | Verifies expected behavior under normal/valid conditions | Asserts success, valid output, expected state, no exceptions for valid input |

| negative | Verifies correct handling of invalid input, errors, or edge cases | Asserts exceptions, error codes, validation failures, rejects bad input |

| boundary | Tests limits, thresholds, empty/null/None/nil inputs, min/max values | Operates on 0, -1, int.MaxValue / sys.maxsize / Number.MAX_SAFE_INTEGER / math.MaxInt64 / i32::MAX, empty string, null/None/nil/undefined, empty collection, boundary of valid range |

| critical-path | Core workflow that must never break; breakage blocks users | Tests the primary success scenario of a key public API or user-facing feature |

| smoke | Quick sanity check that the system is operational | Fast, no complex setup, verifies basic wiring (e.g., service resolves, endpoint returns 200) |

| regression | Reproduces a specific previously-reported bug | References a bug ID, issue number, or describes a fix in its name or comments |

| integration | Crosses process, network, or persistence boundaries | Uses real database, HTTP client, file system, external service, or multi-component setup |

| end-to-end | Full user workflow spanning the entire application stack | Exercises a complete scenario from entry point to final result, distinct from single-boundary integration |

| performance | Validates timing, throughput, or resource consumption | Asserts on elapsed time, memory, allocations, or uses benchmark harness (BenchmarkDotNet, pytest-benchmark, benchmark.js, JMH, go test -bench, criterion.rs, XCTMetric, kotlinx-benchmark, Google Benchmark) |

| security | Verifies authentication, authorization, input sanitization, or secrets handling | Tests for SQL injection, XSS, CSRF, unauthorized access, token validation, permission checks |

| concurrency | Validates thread safety, parallelism, or async correctness | Uses Task.WhenAll / Parallel.ForEach / SemaphoreSlim (.NET); asyncio.gather / threading.Lock / multiprocessing (Python); Promise.all / worker threads (JS/TS); CompletableFuture / ExecutorService / synchronized (Java); go func / sync.WaitGroup / sync.Mutex / chan (Go); Mutex / Thread.new (Ruby); tokio::spawn / Arc<Mutex<_>> / crossbeam (Rust); DispatchQueue / actor (Swift); coroutineScope / Mutex (Kotlin); Start-Job / RunspacePool (PowerShell); std::thread / std::mutex (C++); reproduces race conditions |

| resilience | Tests retry logic, timeouts, circuit breakers, or graceful degradation | Asserts behavior under transient failures, network drops, or service unavailability (e.g., Polly, tenacity, p-retry, resilience4j, hystrix, opossum, retry-go) |

| destructive | Mutates shared or external state that is hard to roll back | Deletes records, drops resources, modifies global config -- useful for CI isolation decisions |

| configuration | Verifies settings loading, defaults, environment behavior | Tests missing config keys, invalid values, environment variable fallbacks, options validation |

| flaky | Known to intermittently fail (meta-tag for test health tracking) | Mark tests the team knows are unreliable; used to quarantine or prioritize stabilization |

A single test may have multiple traits (e.g., both negative and boundary). At minimum, every test should receive one of positive or negative.

Workflow

Step 1: Detect the language, framework, and tagging capability

Identify the codebase's language and test framework. Call the test-analysis-extensions skill and read the matching extension file. The extension file declares a tag-support capability for each framework:

  • auto-edit — framework has canonical tag syntax this skill can safely insert (.NET [TestCategory] / [Trait] / [Category] / [Property], pytest @pytest.mark.<name>, JUnit 5 @Tag("..."), TestNG groups = {"..."}, RSpec metadata it "..." , :tag => true, Pester -Tag '...', Kotest @Tags(...), Swift Testing @Tag(.tagName), Catch2 [tag], doctest * doctest::test_suite("tag") decorator).
  • report-only — framework has no canonical, agreed-upon tag attribute; report tags in a Markdown table only and do not edit source (Go standard testing without build-tag conventions, Jest/Vitest without consistent describe-prefix convention, Rust without project-specific cfg conventions, XCTest without a test plan, GoogleTest without test-name prefix conventions, Mocha without describe-prefix conventions).
  • convention-based — framework uses naming or file conventions for tagging (Go //go:build integration build tags, file-name suffixes like *_integration_test.go, GoogleTest INTEGRATION_* filter prefix). Only emit canonical edits when the user has confirmed the project convention; otherwise treat as report-only.

Capture the capability before Step 4.

Step 2: Scan existing traits

Check which tests already have trait attributes. Use the loaded language extension as the source of truth — examples:

| Framework | Existing Attribute | Example |

|-----------|--------------------|---------|

| MSTest | [TestCategory("...")] | [TestCategory("positive")] |

| xUnit | [Trait("Category", "...")] | [Trait("Category", "positive")] |

| NUnit | [Category("...")] | [Category("positive")] |

| TUnit | [Property("Category", "...")] | [Property("Category", "positive")] |

| JUnit 5 | @Tag("...") | @Tag("positive") |

| TestNG | @Test(groups = {"..."}) | @Test(groups = {"positive"}) |

| pytest | @pytest.mark.<name> | @pytest.mark.positive |

| RSpec | metadata after it | it "...", :positive do |

| Pester | -Tag '...' | It '...' -Tag 'positive' |

| Kotest | @Tags(...) | @Tags(Positive) |

| Swift Testing | @Tag(.<name>) | @Test(.tags(.positive)) |

| Catch2 | [tag] in name | TEST_CASE("...", "[positive]") |

| doctest | * doctest::test_suite("...") decorator | TEST_CASE("..." *doctest::test_suite("positive")) |

Record which tests already have tags to avoid duplication.

Step 3: Classify each test method

For each test method without traits, analyze:

  • Method name -- names containing Invalid, Fail, Error, Throw, Reject, BadInput, Null, None, Nil, Negative, raises_, _throws_, _returns_error suggest negative
  • Assertion type -- Assert.ThrowsException / Assert.Throws / Should().Throw() / pytest.raises / expect(fn).toThrow / assertThrows / assert.Error(t, err) / expect { ... }.to raise_error / #[should_panic] / XCTAssertThrowsError / Should -Throw / EXPECT_THROW suggest negative
  • Input values -- null / None / nil / undefined, "", 0, -1, int.MaxValue / sys.maxsize / Number.MAX_SAFE_INTEGER / math.MaxInt64 / i32::MAX, empty collections suggest boundary
  • Setup complexity -- minimal setup with basic assertions suggests smoke; external dependencies (file/db/net/env) suggest integration
  • Comments and names -- references to issue numbers or "regression" / "bug" / "fix for #..." suggest regression
  • Timing assertions -- Stopwatch, BenchmarkDotNet, elapsed-time checks; pytest-benchmark fixtures; benchmark.js; JMH @Benchmark; go test -bench; criterion.rs; XCTMetric; Google Benchmark; kotlinx-benchmark suggest performance
  • Feature centrality -- tests on primary public API entry points or critical user workflows suggest critical-path
  • Security patterns -- validates auth, checks permissions, sanitizes input, tests for injection, handles tokens/secrets suggest security
  • Parallel/async constructs -- per-language concurrency primitives (see Trait Taxonomy table) suggest concurrency

10. Fault injection -- simulates failures, tests retries, timeouts, or circuit breakers suggest resilience

11. State mutation -- deletes external records, drops resources, modifies shared/global state suggest destructive

12. Full-stack flow -- test spans entry point through data layer to final response, covering a complete user scenario suggest end-to-end

13. Config/settings -- loads configuration, tests missing keys, validates options, checks environment variables suggest configuration

14. Known instability -- test has skip / ignore annotations with comments about flakiness, or names contain "flaky" / "intermittent" suggest flaky

15. Default -- if the test verifies a normal success path, tag positive

When in doubt between positive and negative, read the assertion: if it asserts success -> positive; if it asserts failure -> negative.

Step 4: Apply trait attributes (or report only)

If the loaded language extension declares auto-edit for the framework, add the appropriate attribute to each test method. Place trait attributes adjacent to the existing test attribute. Examples:

MSTest:

[TestMethod]
[TestCategory("negative")]
[TestCategory("boundary")]
public void Parse_NullInput_ThrowsArgumentNullException() { ... }

xUnit:

[Fact]
[Trait("Category", "positive")]
[Trait("Category", "critical-path")]
public void CreateOrder_ValidItems_ReturnsConfirmation() { ... }

NUnit:

[Test]
[Category("regression")]
[Category("negative")]
public void Calculate_OverflowInput_ReturnsError() // Fix for #1234
{ ... }

pytest:

@pytest.mark.negative
@pytest.mark.boundary
def test_parse_none_input_raises_value_error():
    ...

JUnit 5:

@Test
@Tag("positive")
@Tag("critical-path")
void createOrder_validItems_returnsConfirmation() { ... }

TestNG:

@Test(groups = {"negative", "boundary"})
public void parse_nullInput_throwsIllegalArgumentException() { ... }

RSpec:

it "rejects null input", :negative, :boundary do
  ...
end

Pester:

It 'Rejects null input' -Tag 'negative','boundary' {
    ...
}

Kotest:

@Tags(Negative, Boundary)
class ParserSpec : StringSpec({
    "rejects null input" { ... }
})

Swift Testing:

@Test(.tags(.negative, .boundary))
func parseNullInputThrows() throws { ... }

Catch2:

TEST_CASE("Parse null input throws", "[negative][boundary]") { ... }

If the loaded language extension declares report-only for the framework (Go standard testing, plain Jest/Vitest without convention, Rust without project-specific cfg, plain XCTest, plain GoogleTest, plain Mocha), do NOT modify source files. Instead emit a Markdown table mapping each test to its suggested tags, and recommend a project-wide convention the team can adopt (build tags, file suffix, describe-block prefix, GoogleTest filter prefix, test-plan grouping, etc.).

If the loaded language extension declares convention-based (e.g., Go //go:build integration, *_integration_test.go, GoogleTest INTEGRATION_* prefix), only emit canonical edits when the user has confirmed the project's convention. Otherwise treat as report-only.

Step 5: Generate trait summary

After tagging, produce a summary table:

## Trait Distribution

| Trait         | Count | % of Total |
|---------------|-------|------------|
| positive      |    42 |      53.8% |
| negative      |    22 |      28.2% |
| boundary      |     8 |      10.3% |
| critical-path |    12 |      15.4% |
| smoke         |     3 |       3.8% |
| regression    |     5 |       6.4% |
| integration   |     4 |       5.1% |
| end-to-end    |     2 |       2.6% |
| performance   |     1 |       1.3% |
| security      |     3 |       3.8% |
| concurrency   |     2 |       2.6% |
| resilience    |     1 |       1.3% |
| destructive   |     1 |       1.3% |
| configuration |     2 |       2.6% |
| flaky         |     1 |       1.3% |
| **Total tests** | **78** | -- |

Note: Percentages exceed 100% because tests can have multiple traits.

Include observations such as:

  • Ratio of positive to negative tests
  • Whether critical-path tests exist for key public APIs
  • Any tests that could not be confidently classified (list them for manual review)

Validation

  • [ ] Every test method has at least one trait classification (positive or negative at minimum) — in the report for report-only frameworks, or as an attribute for auto-edit frameworks
  • [ ] No invented trait values outside the taxonomy table
  • [ ] Existing trait attributes were preserved, not duplicated
  • [ ] The trait summary table was generated
  • [ ] For auto-edit frameworks, the project still builds / tests still discover after changes (dotnet build / pytest --collect-only / mvn test-compile / go vet ./... / cargo check --tests / npm run test:list / Invoke-Pester -PassThru -Skip / equivalent)
  • [ ] For report-only frameworks, no source files were modified
  • [ ] For convention-based frameworks, edits were applied ONLY when a project convention was confirmed

Common Pitfalls

| Pitfall | Solution |

|---------|----------|

| Guessing traits without reading the test body | Always read assertions and setup to classify accurately |

| Tagging a test only as boundary without positive/negative | Every test should also be positive or negative -- boundary is additive |

| Using the wrong attribute syntax for the detected framework | Match the attribute style to the loaded language extension (don't put [TestCategory] in an xUnit project or @pytest.mark.x in a unittest test) |

| Duplicating an existing category attribute | Check for pre-existing traits in Step 2 before adding |

| Over-tagging as critical-path | Reserve for tests on primary public entry points, not every helper |

| Editing Go / plain Jest / plain Rust / plain XCTest / plain GoogleTest source | These are report-only by default — emit a Markdown table instead. Only edit if the user confirms a project-wide convention (build tag, file suffix, describe-prefix, test-plan grouping). |

| Inventing tag prefixes for convention-based frameworks | Confirm the project's existing convention before adopting one — don't guess between _integration_test.go, //go:build integration, or IntegrationTest prefix |

| Missing language-specific concurrency / async primitives | Each language has its own primitives — read the loaded language extension and the Trait Taxonomy concurrency row before classifying as concurrency |

How to use it

Copy the folder

Take dotnet/test-tagging from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.