use a file instead of marker comment

scripts/run-related-test.mjs

@@ -1,47 +1,16 @@
 /**
- * This script finds all files under the paths that contain a marker and reads lines after the marker from the files.
- * The marker is defined as a comment line that starts with `// TEST:`.
+ * This script finds all `.tests` files under the paths and reads lines from these files.
  * The script is useful to find all related test cases for a given code change.
  * Usage: `node scripts/run-related-test.mjs <path1> <path2> ...`
  */
 
 import { promisify } from 'node:util'
 import { exec as execOrg } from 'node:child_process'
+import { readFile, constants, access } from 'node:fs/promises'
+import { dirname, join } from 'node:path'
 
 const exec = promisify(execOrg)
 
-/**
- * Find all files under the paths that contain a marker
- * @param {string[]} paths - Paths to search in
- * @param {string} marker - Marker to search for
- */
-async function findFiles(paths, marker) {
-  const foundPaths = []
-  for (const path of paths) {
-    const command = `find "${path}" -type f -exec grep -l "${marker}" {} +`
-    const { stdout } = await exec(command).catch((e) => e)
-    foundPaths.push(...stdout.trim().split('\n'))
-  }
-  return foundPaths.filter(Boolean)
-}
-
-/**
- * Read lines after the marker from a file
- * @param {string} filePath - File path to read
- * @param {string} marker - Marker to search for
- */
-async function readTestLines(filePath, marker) {
-  const escapedMarker = marker.replaceAll('/', '\\/')
-  let command = `awk '/${escapedMarker}/{flag=1;next}/^$/{flag=0}flag' ${filePath}`
-  command += ' | sort | uniq' // Sort and remove duplicates
-  const { stdout } = await exec(command)
-
-  return stdout
-    .trim()
-    .replace(/^\/\/ /gm, '') // Remove the '// ' comment prefix
-    .split('\n')
-}
-
 /**
  * Get all changed files from git under the packages directory
  * @returns {Promise<string[]>} - List of changed files
@@ -56,12 +25,22 @@ async function getChangedFilesFromPackages(baseBranch = 'origin/canary') {
 
 export async function getRelatedTests(args = []) {
   const paths = args.length ? args : await getChangedFilesFromPackages()
-  const marker = '// TEST:'
-  const files = await findFiles(paths, marker)
-  const lines = []
-  for (const file of files) lines.push(...(await readTestLines(file, marker)))
+  const relatedTestFile = '.tests'
+  const tests = []
+  for (const path of paths) {
+    const testFile = join(dirname(path), relatedTestFile)
+    const hasRelatedTests = await access(testFile, constants.F_OK)
+      .then(() => true)
+      .catch(() => false)
+
+    if (hasRelatedTests) {
+      const content = await readFile(testFile, 'utf-8')
+      const lines = content.split('\n').filter(Boolean)
+      tests.push(...lines)
+    }
+  }
 
-  return Array.from(new Set(lines))
+  return Array.from(new Set(tests))
 }
 
-// console.log(await getRelatedTest(process.argv.slice(2)))
+// console.log(await getRelatedTests(process.argv.slice(2)))