add: unit and integration testing

app/node_modules/istanbul-lib-instrument/src/constants.js

@@ -0,0 +1,14 @@
+const { createHash } = require('crypto');
+const { name } = require('../package.json');
+// TODO: increment this version if there are schema changes
+// that are not backwards compatible:
+const VERSION = '4';
+
+const SHA = 'sha1';
+module.exports = {
+    SHA,
+    MAGIC_KEY: '_coverageSchema',
+    MAGIC_VALUE: createHash(SHA)
+        .update(name + '@' + VERSION)
+        .digest('hex')
+};