refactor: centralize Oxlint worker bounds

scripts/run-oxlint.spec.ts

@@ -0,0 +1,28 @@
+import { describe, expect, it } from 'vitest'
+import { resolveOxlintInvocation } from './run-oxlint.ts'
+
+describe('Oxlint invocation', () => {
+  it('preserves the ordinary default invocation', () => {
+    expect(resolveOxlintInvocation(['.'], { PATH: '/bin' })).toEqual({
+      args: ['.'],
+      env: { PATH: '/bin' },
+    })
+  })
+
+  it('bounds both worker pools from one setting', () => {
+    expect(resolveOxlintInvocation(['.', '--fix'], { DSH_OXLINT_THREADS: '4', GOMAXPROCS: '12' })).toEqual({
+      args: ['.', '--fix', '--threads=4'],
+      env: { DSH_OXLINT_THREADS: '4', GOMAXPROCS: '4' },
+    })
+  })
+
+  it.each(['0', '-1', '1.5', 'auto'])('rejects invalid worker bound %s', (value) => {
+    expect(() => resolveOxlintInvocation(['.'], { DSH_OXLINT_THREADS: value }))
+      .toThrow('DSH_OXLINT_THREADS must be a positive integer')
+  })
+
+  it('rejects a competing direct worker bound', () => {
+    expect(() => resolveOxlintInvocation(['.', '--threads=2'], { DSH_OXLINT_THREADS: '4' }))
+      .toThrow('use DSH_OXLINT_THREADS instead')
+  })
+})