test: drop vitest and standardize on bun:test

CLAUDE.md

@@ -98,7 +98,8 @@ Commands use `withErrorHandling()` HOF which:
 
 ## Testing Notes
 
-- `bun run test` uses vitest; CI runs `bun test` (bun's native runner). They have different semantics — verify both locally before pushing.
+- Tests use bun's native runner (`bun test`, imports from `bun:test`); `bun run test` is an alias. Keep a single runner so CI exercises the same suite, dependencies, and lockfile that local runs do.
+- `pipe-truncation.test.ts` runs against `dist/cli.js`, so run `bun run build` before `bun test`.
 - Bun's native test runner snapshots any `process.exitCode` mutation during a test and uses it as the suite's exit code, even when reverted. Tests that need to assert exit behavior must run the code in a child process.
 
 ## Date Handling

package.json

@@ -15,7 +15,7 @@
     "format": "bun run biome format --write src",
     "format:check": "bun run biome format src",
     "typecheck": "bun run tsc --noEmit",
-    "test": "bun run vitest run",
+    "test": "bun test",
     "link": "bun run build && bun link",
     "prepublishOnly": "bun run build"
   },
@@ -58,7 +58,6 @@
     "@types/bun": "latest",
     "oxlint": "^1.38.0",
     "tsup": "^8.0.0",
-    "typescript": "^5.7.2",
-    "vitest": "^5.0.0"
+    "typescript": "^5.7.2"
   }
 }

src/lib/__tests__/display.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect } from 'vitest';
+import { describe, it, expect } from 'bun:test';
 import { formatEstimate, isTaskOverdue, formatTags, pluralize } from '../display.js';
 import type { Task } from '../../types.js';
 

src/lib/__tests__/errors.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, beforeAll } from 'vitest';
+import { describe, it, expect } from 'bun:test';
 import { execFile } from 'child_process';
 import { promisify } from 'util';
 import { mkdtemp, writeFile, rm } from 'fs/promises';
@@ -74,10 +74,6 @@ handleError(error);
 }
 
 describe('handleError', () => {
-  beforeAll(() => {
-    // Sanity check the helper compiles cleanly; nothing else needed.
-  });
-
   it('exits with code 1 instead of calling process.exit', async () => {
     const { exitCode } = await runHandleError('error_plain');
     expect(exitCode).toBe(1);

src/lib/__tests__/pipe-truncation.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, beforeAll } from 'vitest';
+import { describe, it, expect, beforeAll } from 'bun:test';
 import { spawn, execFile } from 'child_process';
 import { promisify } from 'util';
 import { existsSync, readFileSync } from 'fs';