code: function loadSimpleResourceMap(config) {
      return new Promise((resolve, reject) => {
  
          // Convert Jest config into glob pattern.
          let testPathDirs;
          let testFileExtensions;
          let generatedGlob;
  
          if (config.testPathDirs.length === 1) {
              testPathDirs = config.testPathDirs[0];
          } else {
              testPathDirs = '{' + config.testPathDirs.join(',') + '}';
          }
  
          if (config.testFileExtensions.length === 1) {
              testFileExtensions = config.testFileExtensions[0];
          } else {
              testFileExtensions = '{' + config.testFileExtensions.join(',') + '}';
          }
  
          generatedGlob = testPathDirs + '/' +
              '**/' + config.testDirectoryName + '/**/*.' + testFileExtensions;
  
          glob(generatedGlob, (err, files) => {
              if (err) {
                  reject(err);
              } else {
                  let resourceMap;
                  resourceMap = {
                      resourcePathMap: {}
                  };
                  files.forEach(file => {
                      let fullPath = path.resolve(file);
                      resourceMap.resourcePathMap[fullPath] = {
                          path: fullPath
                      };
                  });
                  resolve(resourceMap);
              }
          });
      });
  }
docs: Builds simple resource map containing only the bundled test files.
  @param  {Object}  config The Jest config.
  @return {Promise}        The 'node-haste'(ish) resource map.