Meteor import directory test files not eagerly loading

Meteor version 1.7.0.5
Using meteortesting:mocha

I have a very simple meteor react app. I added a test file in imports/startup/simple-schema.tests.js

describe('Todos_item', function () {
  console.log('Todo');
});

I was running npm run test-app so it should be logged in console but that file actually doesn't run. But when I added this snippet to my tests/main.js Todo is logged in console. So am I missing something.

My directory tree

package.json

{
  "name": "meteor-bootstrap",
  "private": true,
  "scripts": {
    "start": "meteor run",
    "test": "meteor test --once --driver-package meteortesting:mocha",
    "test-app": "TEST_WATCH=1 meteor test --full-app --driver-package meteortesting:mocha",
    "visualize": "meteor --production --extra-packages bundle-visualizer"
  },
  "dependencies": {
    "@babel/runtime": "7.0.0-beta.55",
    "meteor-node-stubs": "^0.4.1",
    "react": "^16.4.2",
    "react-dom": "^16.4.2",
    "react-router-dom": "^4.3.1",
    "simpl-schema": "^1.5.3"
  },
  "meteor": {
    "mainModule": {
      "client": "client/main.js",
      "server": "server/main.js"
    },
    "testModule": "tests/main.js"
  },
  "engines": {
    "node": "8.11.4"
  }
}

Any help will be greatly appreciated. Thanks in advance.