无法运行Gulp-Mocha，伊斯坦布尔的单元测试

Question

我正在研究gulp-mocha和gulp-Istanbul，但是当我运行命令gulp-mocha 错误出现在屏幕上。我是新手，并尝试在我的项目中构建单元测试

这是我的gulpfile.babel.js

import gulp from 'gulp';
import gulpLoadPlugins from 'gulp-load-plugins';
import path from 'path';
import del from 'del';
import runSequence from 'run-sequence';
import babelCompiler from 'babel-core/register';
import * as isparta from 'isparta';
import babel from 'gulp-babel';

const plugins = gulpLoadPlugins();

const paths = {
  js: ['./**/*.js', '!dist/**', '!node_modules/**', '!coverage/**'],
  nonJs: ['./package.json', './.gitignore', './**/*.ejs'],
  tests: './server/tests/*.js'
};

const options = {
  codeCoverage: {
    reporters: ['lcov', 'text-summary'],
    thresholds: {
      global: {
        statements: 50, branches: 50, functions: 50, lines: 50
      }
    }
  }
};

// Clean up dist and coverage directory
gulp.task('clean', () =>
  del(['dist/**', 'coverage/**', '!dist', '!coverage']));

// Set env variables
gulp.task('set-env', () => {
  plugins.env({
    vars: {
      NODE_ENV: 'test'
    }
  });
});

// Lint Javascript
gulp.task('lint', () =>
  gulp.src(paths.js)
    // eslint() attaches the lint output to the "eslint" property
    // of the file object so it can be used by other modules.
    .pipe(plugins.eslint())
    // eslint.format() outputs the lint results to the console.
    // Alternatively use eslint.formatEach() (see Docs).
    .pipe(plugins.eslint.format())
    // To have the process exit with an error code (1) on
    // lint error, return the stream and pipe to failAfterError last.
    .pipe(plugins.eslint.failAfterError()));

// Copy non-js files to dist
gulp.task('copy', () =>
  gulp.src(paths.nonJs)
    .pipe(plugins.newer('dist'))
    .pipe(gulp.dest('dist')));

// Compile ES6 to ES5 and copy to dist
gulp.task('babel', () =>
  gulp.src([...paths.js, '!gulpfile.babel.js'], { base: '.' })
    .pipe(plugins.newer('dist'))
    .pipe(plugins.sourcemaps.init())
    .pipe(babel())
    .pipe(plugins.sourcemaps.write('.', {
      includeContent: false,
      sourceRoot(file) {
        return path.relative(file.path, __dirname);
      }
    }))
    .pipe(gulp.dest('dist')));

// Start server with restart on file changes
gulp.task('nodemon', ['copy', 'babel'], () =>
  plugins.nodemon({
    script: path.join('dist', 'index.js'),
    ext: 'js',
    ignore: ['node_modules/**/*.js', 'dist/**/*.js'],
    tasks: ['copy', 'babel']
  }));

// covers files for code coverage
gulp.task('pre-test', () =>
  gulp.src([...paths.js, '!gulpfile.babel.js'])
    // Covering files
    .pipe(plugins.istanbul({
      instrumenter: isparta.Instrumenter,
      includeUntested: true
    }))
    // Force `require` to return covered files
    .pipe(plugins.istanbul.hookRequire()));

// triggers mocha test with code coverage
gulp.task('test', ['pre-test', 'set-env'], () => {
  let reporters;
  let exitCode = 0;
  if (plugins.util.env['code-coverage-reporter']) {
    reporters = [...options.codeCoverage.reporters, plugins.util.env['code-coverage-reporter']];
  } else {
    reporters = options.codeCoverage.reporters;
  }

  return gulp.src([paths.tests], { read: false })
    .pipe(plugins.plumber())
    .pipe(plugins.mocha({
      reporter: plugins.util.env['mocha-reporter'] || 'spec',
      ui: 'bdd',
      timeout: 11000,
      compilers: {
        js: babelCompiler,
      }
    }))
    .once('error', (err) => {
      plugins.util.log(err);
      exitCode = 1;
    })
    // Creating the reports after execution of test cases
    .pipe(plugins.istanbul.writeReports({
      dir: './coverage',
      reporters,
    }))
    // Enforce test coverage
    .pipe(plugins.istanbul.enforceThresholds({
      thresholds: options.codeCoverage.thresholds,
    }))
    .once('end', () => {
      plugins.util.log('completed !!');
      process.exit(exitCode);
    });
});

// clean dist, compile js files, copy non-js files and execute tests
gulp.task('mocha', ['clean'], () => {
  runSequence(
    ['copy', 'babel'],
    'test',
  );
});

// gulp serve for development
gulp.task('serve', ['clean'], () => runSequence('nodemon'));

// default task: clean dist, compile js files and copy non-js files.
gulp.task('default', ['clean'], () => {
  runSequence(['copy', 'babel']);
});

这是我面临的错误

我不知道为什么错误会发生在我身上，有人能建议我解决该错误的解决方案或解释为什么会发生这种情况吗