JavaScript regular expression to find headers in an HTTP response

HttpHeaderRegex.js

TestCase('regex to find HTTP headers', {
  
  headerFinderRegex: /^([-!#-'*+.0-9A-Z^-z|~]+:)/gm,
  
  'test only valid headers are highlighted': function () {
    var addValue = function(s) { return s + ' value\n';},
        addColon = function(s) { return s + ':';},
        wrapWithStrong = function(s) { return "<strong>" + s + "</strong>";},
        invalidCharacters = (function() {
            var invalidCharacters = ["(", ")", "<", ">", "@", ",", ";", ":", "\\", '"', "/", "[", "]", "?", "=", "{", "}", ' ', '\t'];
            for (var i = 0; i < 32; i++) {
              invalidCharacters.push(String.fromCharCode(i));
            }

            invalidCharacters.push(String.fromCharCode(127));

            return invalidCharacters;
        }()),
        invalidHeaders = invalidCharacters.map(addColon).map(addValue).join(''),
        validHeadersNames = ['Accept', '42!What', 'x-header'].map(addColon);

    assertEquals(invalidHeaders, invalidHeaders.replace(this.headerFinderRegex, "<strong>$1</strong>"));
    assertEquals(validHeadersNames.map(wrapWithStrong).map(addValue).join(''), validHeadersNames.map(addValue).join('').replace(this.headerFinderRegex, "<strong>$1</strong>"));
  }
});