code: function assertSubstrings(str, substrings) {
    substrings.forEach(function(substring) {
      assert(str.indexOf(substring) !== -1, str +
        ' - string does not contain: ' + substring);
    });
  }
docs: Asserts that each substring is present in the supplied string.
  
  @param {string}   str
  @param {string[]} substrings