add test for check function

Author: pcarleton

jest.config.js

@@ -0,0 +1,8 @@
+export default {
+  preset: 'ts-jest/presets/default-esm',
+  extensionsToTreatAsEsm: ['.ts'],
+  testEnvironment: 'node',
+  moduleNameMapper: {
+    '^(\\.{1,2}/.*)\\.js$': '$1',
+  },
+};