Replace bash test runner with TypeScript

package.json

@@ -10,7 +10,7 @@
   "scripts": {
     "prebuild": "tsx scripts/rmrf.ts lib dist",
     "build": "tsx scripts/build.ts",
-    "test": "scripts/run_tests.bash",
+    "test": "tsx scripts/run_tests.ts",
     "typecheck": "tsc",
     "repl": "tsx"
   },

scripts/run_tests.ts

@@ -0,0 +1,19 @@
+import { readdirSync } from 'node:fs';
+import { join } from 'path';
+import { execFileSync } from 'node:child_process';
+
+// TODO: Update with enabling withFileTypes if fixed the feature
+//
+// Do NOT specify both recursive and withFileTypes as true, entries will be missed in v20.5.1
+//   - https://github.com/kachick/times_kachick/issues/244
+//   - https://github.com/nodejs/node/pull/48698
+const baseNames = readdirSync('src', { encoding: 'utf-8', recursive: true, withFileTypes: false });
+
+const testPaths = baseNames.flatMap((name) => name.endsWith('.test.ts') ? [join('src', name)] : []);
+
+console.log('Starting to run tests for', testPaths);
+
+execFileSync('node', ['--loader', 'tsx', '--no-warnings', '--test', ...testPaths], {
+  // preserving color: https://github.com/nodejs/help/issues/2183#issuecomment-532362821
+  stdio: 'inherit',
+});