metamask-extension/test/unit/migrations/035-test.js

const assert = require('assert')
const migration35 = require('../../../app/scripts/migrations/035')

describe('migration #35', () => {
  it('should update the version metadata', (done) => {
    const oldStorage = {
      meta: {
        version: 34,
      },
      data: {},
    }

    migration35.migrate(oldStorage)
      .then((newStorage) => {
        assert.deepEqual(newStorage.meta, {
          'version': 35,
        })
        done()
      })
      .catch(done)
  })

  it('should delete seedWords', (done) => {
    const oldStorage = {
      meta: {},
      data: {
        PreferencesController: {
          seedWords: 'seed words',
        },
      },
    }

    migration35.migrate(oldStorage)
      .then((newStorage) => {
        assert.deepEqual(newStorage.data.PreferencesController, {})
        done()
      })
      .catch(done)
  })

  it('should delete falsy seedWords', (done) => {
    const oldStorage = {
      meta: {},
      data: {
        PreferencesController: {
          seedWords: '',
        },
      },
    }

    migration35.migrate(oldStorage)
      .then((newStorage) => {
        assert.deepEqual(newStorage.data.PreferencesController, {})
        done()
      })
      .catch(done)
  })

  it('should leave state without seedWords unchanged', (done) => {
    const oldStorage = {
      meta: {},
      data: {
        PreferencesController: {
          frequentRpcListDetail: [],
          currentAccountTab: 'history',
          accountTokens: {},
          assetImages: {},
          tokens: [],
          suggestedTokens: {},
          useBlockie: false,
          knownMethodData: {},
          participateInMetaMetrics: null,
          firstTimeFlowType: null,
          currentLocale: 'en',
          identities: {},
          lostIdentities: {},
          forgottenPassword: false,
          preferences: {
            useNativeCurrencyAsPrimaryCurrency: true,
          },
          completedOnboarding: false,
          migratedPrivacyMode: false,
          metaMetricsId: null,
          metaMetricsSendCount: 0,
        },
      },
    }

    migration35.migrate(oldStorage)
      .then((newStorage) => {
        assert.deepEqual(newStorage.data, oldStorage.data)
        done()
      })
      .catch(done)
  })
})