add .mts support

Author: davidjgoss

src/configuration/from_file.ts

@@ -105,6 +105,12 @@ async function loadFile(
       )
       definitions = await import(pathToFileURL(filePath).toString())
       break
+    case '.mts':
+      logger.debug(
+        `Loading configuration file "${file}" as ESM TypeScript based on extension`
+      )
+      definitions = await import(pathToFileURL(filePath).toString())
+      break
     case '.js':
       {
         const parentPackage = await readPackageJson(filePath)

src/configuration/from_file_spec.ts

@@ -220,6 +220,16 @@ p1:
       expect(result).to.deep.eq({ paths: ['other/path/*.feature'] })
     })
 
+    it('should work with .mts', async () => {
+      const { logger, cwd } = await setup(
+        'cucumber.mts',
+        `export default {}; export const p1 = {paths: ['other/path/*.feature']}`
+      )
+
+      const result = await fromFile(logger, cwd, 'cucumber.mts', ['p1'])
+      expect(result).to.deep.eq({ paths: ['other/path/*.feature'] })
+    })
+
     it('should throw for an unsupported format', async () => {
       const { logger, cwd } = await setup('cucumber.foo', `{}`)
       try {