Test migration to jest by hand

Apparently using regular expressions is way easier.

test/toDecimalMark/toDecimalMark.test.js

@@ -0,0 +1,9 @@
+const expect = require('expect');
+const toDecimalMark = require('./toDecimalMark.js');
+
+
+  test('toDecimalMark is a Function', () => {
+  expect(toDecimalMark).toBeInstanceOf(Function);
+});
+  t.equal(toDecimalMark(12305030388.9087), "12,305,030,388.909", "convert a float-point arithmetic to the Decimal mark form");
+