Ignore test file with no metaltest exported

suite.js

@@ -30,6 +30,7 @@ import { consolereporter, totalreporter } from 'metaltest'
 const suite = async (folder = '.') => {
   const absolutePaths = getStackAbsolutePaths()
   const absolutePath = absolutePaths[2]
+  const fileIgnored = []
 
   const total = totalreporter()
 
@@ -40,9 +41,19 @@ const suite = async (folder = '.') => {
 
     const module = join(absolutePath, file)
     const { test } = await import(module)
+
+    if (test === undefined) {
+      fileIgnored.push(file)
+      continue
+    }
+
     await test.run(consolereporter(), total)
   }
 
+  for (const file of fileIgnored) {
+    console.log(`The file ${file} doesn't export the metaltest object`)
+  }
+
   console.log(total.msg())
 }