Target test modules with a glob.

This avoids the Node.js test runner automatically attempting to run all modules in the `test` directory.

package.json

@@ -86,7 +86,7 @@
     "eslint": "eslint .",
     "prettier": "prettier -c .",
     "types": "tsc -p jsconfig.json",
-    "tests": "coverage-node --test-reporter=spec --test",
+    "tests": "coverage-node --test-reporter=spec --test *.test.mjs",
     "test": "npm run eslint && npm run prettier && npm run types && npm run tests",
     "prepublishOnly": "npm test"
   }