mocha のテストに無理やり連番を振って番号指定でテスト実行できるようにする ref: https://qiita.com/tily/items/767d1d5acaabe9dcf4fb

file0.txt

const Mocha = require("mocha");

const originalRun = Mocha.prototype.run;

Mocha.prototype.run = function (fn) {
  let i = 1
  this.loadFiles(() => {
    this.suite.eachTest((test) => {
      test.title = `#${i}: ${test.title}`
      i += 1
    })
  })
  return originalRun.apply(this, [fn])
}

file1.txt

const assert = require("assert");
describe("Numbered tests", ()=> {
  for(let i = 0; i < 15; i += 1) {
    it("test hogehoge", () => {
      assert(1 == 1)
    })
  }
})

file2.txt

$ mocha --require mocha_ext.js test.js


  Numbered tests
    ✓ #1: test hogehoge
    ✓ #2: test hogehoge
    ✓ #3: test hogehoge
    ✓ #4: test hogehoge
    ✓ #5: test hogehoge
    ✓ #6: test hogehoge
    ✓ #7: test hogehoge
    ✓ #8: test hogehoge
    ✓ #9: test hogehoge
    ✓ #10: test hogehoge
    ✓ #11: test hogehoge
    ✓ #12: test hogehoge
    ✓ #13: test hogehoge
    ✓ #14: test hogehoge
    ✓ #15: test hogehoge


  15 passing (11ms)

file3.txt

$ mocha --require mocha_ext.js test.js --grep '#8:'


  Numbered tests
    ✓ #8: test hogehoge


  1 passing (10ms)