[TE-6312] Remove nunit runner support

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Changelog
 ## Unreleased
 - **Breaking:** Remove the `pytest-pants` runner. It had zero real usage over the last 3 months. Use the `custom` runner instead, which now supports selector-based test splitting (see `--selector-splitting` in 2.9.0).
+- **Breaking:** Remove the `nunit` runner. It saw almost no real usage, and had known issues splitting tests by file (result path handling, and class name collisions across namespaces).
 
 ## 2.9.0 - 2026-07-06
 - Add experimental selector-based test splitting for supported non-file runners (RSpec, custom runner, Go) via `--selector-splitting` and `--selector-file` (env: `BUILDKITE_TEST_ENGINE_SELECTOR_FILE`), splitting by runnable selector rather than by file. `--selector-file` must be used alongside `--selector-splitting`.

README.md

@@ -6,15 +6,15 @@ bktec supports multiple test runners and offers various features to enhance your
 
 <!-- DO NOT MANUALLY EDIT THE TABLE BELOW. The contents can be generate with `go run util/supported_features/main.go` -->
 
-| Feature | RSpec | Jest | Playwright | Cypress | pytest | gotest | Cucumber | NUnit | Custom test runner |
-| --- | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
-| Split tests by file[^1] | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ |
-| [Split slow files by individual test example](https://github.com/buildkite/test-engine-client/blob/main/docs/rspec.md#split-slow-files-by-individual-test-example) | ✅ | ❌ | ✅ | ❌ | ✅ | ❌ | ✅ | ❌ | ❌ |
-| Filter test files | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ |
-| Filter tests by tag | ❌ | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ | ❌ |
-| Automatically retry failed test | ✅ | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ | ✅ | ❌ |
-| Mute tests (ignore test failures) | ✅ | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ | ✅ | ✅ |
-| Skip tests | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ |
+| Feature | RSpec | Jest | Playwright | Cypress | pytest | gotest | Cucumber | Custom test runner |
+| --- | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
+| Split tests by file[^1] | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ | ✅ |
+| [Split slow files by individual test example](https://github.com/buildkite/test-engine-client/blob/main/docs/rspec.md#split-slow-files-by-individual-test-example) | ✅ | ❌ | ✅ | ❌ | ✅ | ❌ | ✅ | ❌ |
+| Filter test files | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ | ✅ |
+| Filter tests by tag | ❌ | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
+| Automatically retry failed test | ✅ | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ | ❌ |
+| Mute tests (ignore test failures) | ✅ | ✅ | ✅ | ❌ | ✅ | ✅ | ✅ | ✅ |
+| Skip tests | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ | ✅ | ❌ |
 
 ## Installation
 The latest version of bktec can be downloaded from https://github.com/buildkite/test-engine-client/releases
@@ -254,7 +254,6 @@ To configure the test runner for bktec, please refer to the detailed guides prov
 - [go test](./docs/gotest.md)
 - [RSpec](./docs/rspec.md)
 - [Cucumber](./docs/cucumber.md)
-- [NUnit](./docs/nunit.md)
 - [Custom Test Runner](./docs/custom-test-runner.md)
 
 

internal/config/validate.go

@@ -119,7 +119,6 @@ func (c *Config) ValidateForRun() error {
 		"playwright": true,
 		"gotest":     true,
 		"cucumber":   true,
-		"nunit":      true,
 	}
 	if c.ResultPath == "" && runnersWithResultPath[c.TestRunner] {
 		c.errs.appendFieldError("BUILDKITE_TEST_ENGINE_RESULT_PATH", "must not be blank")

internal/runner/detector.go

@@ -37,12 +37,10 @@ func DetectRunner(cfg *config.Config) (TestRunner, error) {
 		return NewGoTest(runnerConfig), nil
 	case "cucumber":
 		return NewCucumber(runnerConfig), nil
-	case "nunit":
-		return NewNUnit(runnerConfig), nil
 	case "custom":
 		return NewCustom(runnerConfig)
 	default:
 		// Update the error message to include the new runner
-		return nil, fmt.Errorf("runner value %q is invalid, possible values are 'rspec', 'jest', 'cypress', 'playwright', 'pytest', 'gotest', 'cucumber', 'nunit', or 'custom'", testRunner)
+		return nil, fmt.Errorf("runner value %q is invalid, possible values are 'rspec', 'jest', 'cypress', 'playwright', 'pytest', 'gotest', 'cucumber', or 'custom'", testRunner)
 	}
 }

internal/runner/doc.go

@@ -1,3 +1,3 @@
 // Package runner provides the test runners that run sets of test cases.
-// Supported runners: rspec, jest, cypress, playwright, pytest, gotest, cucumber, nunit.
+// Supported runners: rspec, jest, cypress, playwright, pytest, gotest, cucumber.
 package runner