Add test runner script

package.json

@@ -13,9 +13,9 @@
   "author": "SAP SE (https://www.sap.com)",
   "license": "Apache-2.0",
   "scripts": {
-    "test:unit": "node --import ./test/unit/setup.mjs --test ./test/unit/*.test.js",
-    "test:integration": "node --import ./test/integration/setup.mjs --test ./test/int/*.test.js",
-    "test:smoke": "node --import ./test/smoke/setup.mjs --test ./test/smoke/*.test.js",
+    "test:unit": "node test/testRunner.js ./test/unit ./test/unit/setup.mjs",
+    "test:integration": "node test/testRunner.js ./test/integration ./test/integration/setup.mjs",
+    "test:smoke": "node test/testRunner.js ./test/smoke ./test/smoke/setup.mjs",
     "test:all": "npm run test:smoke && npm run test:unit",
     "test": "npm run test:smoke && npm run test:unit",
     "lint": "npx eslint .",

test/testRunner.js

@@ -0,0 +1,29 @@
+// TODO: this script wraps the `node --test` command until our lower bound for our test matrix is >=21 (30 Apr 2026).
+// The native test runner with multiple suites requires using a glob pattern to specify the relevant test files.
+// But glob is only available in Node 21 onwards. So to avoid errors where the runtime assumes it has to look for a file called "*.test.js",
+// we wrap the call to node with an explicit glob expansion. Once Node22 is established as lower bound, we can have
+//
+// "test:unit": "node --import ./test/unit/setup.mjs --test './test/unit/*.test.js'",
+// "test:integration": "node --import ./test/integration/setup.mjs --test './test/integration/*.test.js'",
+// "test:smoke": "node --import ./test/smoke/setup.mjs --test './test/smoke/*.test.js'",
+//
+// again.
+const { execSync } = require('child_process')
+const path = require('path')
+const fs = require('fs')
+
+const testDir = process.argv[2]
+const setupFile = process.argv[3]
+
+const testFiles = fs.readdirSync(testDir)
+    .filter(file => file.endsWith('.test.js'))
+    .map(file => path.join(testDir, file))
+
+if (testFiles.length === 0) {
+    // eslint-disable-next-line no-console
+    console.error(`No test files found in ${testDir}`)
+    process.exit(1)
+}
+
+const command = `node --import ${setupFile} --test ${testFiles.join(' ')}`
+execSync(command, { stdio: 'inherit' })