jestでimport文を使うには

{
  "presets": [
    "@babel/preset-react",
    ["@babel/preset-env", {
      "targets": {
        "node": "current",
        "ie":11,
        "safari":9
      },
      "useBuiltIns": "usage",
      "corejs": 3,
      "modules": false
    }],
  ],

if (process.env.NODE_ENV == null) {
process.env.NODE_ENV = 'test'
}

{
  "presets": [
    "@babel/preset-react",
    ["@babel/preset-env", {
      "targets": {
        "node": "current",
        "ie":11,
        "safari":9
      },
      "useBuiltIns": "usage",
      "corejs": 3,
      "modules": false
    }],
  ],
  "env": {
+   /* ここから下がjest用の処理 */
+    "test": {
+      "presets": [
+        "@babel/preset-react",
+        ["@babel/preset-env", {
+          "targets": {
+            "node": "current",
+            "ie":11,
+            "safari":9
+          },
+          "useBuiltIns": "usage",
+          "corejs": 3,
+          "modules": "cjs"
+        }]
+      ]
+    }
  }
}

module.exports = {
  verbose: true,
  transform: {
    '^.+\\.js$': 'babel-jest',
  },
  moduleFileExtensions: ['js'],
};

$ npm i -D babel-jest

export async function addCalcFun(baseValue, addValue) {
  return baseValue + addValue;
}

import { callErrorFun } from './exporter'

describe('エラー', () => {
  it('通常のエラー', () => {
    expect(callErrorFun(2+2)).toBe(5)
  })
})

$ npx jest importer.spec.js