diff --git a/searx/engines/1337x.py b/searx/engines/1337x.py
index 76a7a1634..9e045bc51 100644
--- a/searx/engines/1337x.py
+++ b/searx/engines/1337x.py
@@ -1,7 +1,6 @@
 from urllib.parse import quote, urljoin
 from lxml import html
-from searx.engines.xpath import extract_text
-from searx.utils import get_torrent_size
+from searx.utils import extract_text, get_torrent_size
 
 
 url = 'https://1337x.to/'
diff --git a/searx/engines/acgsou.py b/searx/engines/acgsou.py
index d5d3e3178..7bab64f5b 100644
--- a/searx/engines/acgsou.py
+++ b/searx/engines/acgsou.py
@@ -11,8 +11,7 @@
 
 from urllib.parse import urlencode
 from lxml import html
-from searx.engines.xpath import extract_text
-from searx.utils import get_torrent_size, int_or_zero
+from searx.utils import extract_text, get_torrent_size, int_or_zero
 
 # engine dependent config
 categories = ['files', 'images', 'videos', 'music']
diff --git a/searx/engines/apkmirror.py b/searx/engines/apkmirror.py
index 4e6dcd486..a8ff499af 100644
--- a/searx/engines/apkmirror.py
+++ b/searx/engines/apkmirror.py
@@ -11,7 +11,7 @@
 
 from urllib.parse import urlencode
 from lxml import html
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 
 # engine dependent config
diff --git a/searx/engines/archlinux.py b/searx/engines/archlinux.py
index e2f44b0f5..8f93f4f38 100644
--- a/searx/engines/archlinux.py
+++ b/searx/engines/archlinux.py
@@ -13,7 +13,7 @@
 
 from urllib.parse import urlencode, urljoin
 from lxml import html
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 # engine dependent config
 categories = ['it']
diff --git a/searx/engines/bing.py b/searx/engines/bing.py
index c7b619369..a4fa1db78 100644
--- a/searx/engines/bing.py
+++ b/searx/engines/bing.py
@@ -17,8 +17,7 @@ import re
 from urllib.parse import urlencode
 from lxml import html
 from searx import logger, utils
-from searx.engines.xpath import extract_text
-from searx.utils import match_language, gen_useragent, eval_xpath
+from searx.utils import extract_text, match_language, gen_useragent, eval_xpath
 
 logger = logger.getChild('bing engine')
 
diff --git a/searx/engines/btdigg.py b/searx/engines/btdigg.py
index 2faade3e2..d73ee23a6 100644
--- a/searx/engines/btdigg.py
+++ b/searx/engines/btdigg.py
@@ -13,8 +13,7 @@
 from lxml import html
 from operator import itemgetter
 from urllib.parse import quote, urljoin
-from searx.engines.xpath import extract_text
-from searx.utils import get_torrent_size
+from searx.utils import extract_text, get_torrent_size
 
 # engine dependent config
 categories = ['videos', 'music', 'files']
diff --git a/searx/engines/deviantart.py b/searx/engines/deviantart.py
index 2bd21fa5d..b91816daa 100644
--- a/searx/engines/deviantart.py
+++ b/searx/engines/deviantart.py
@@ -15,7 +15,7 @@
 from lxml import html
 import re
 from urllib.parse import urlencode
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 
 # engine dependent config
diff --git a/searx/engines/digbt.py b/searx/engines/digbt.py
index e2c0389c6..b1a90fb2f 100644
--- a/searx/engines/digbt.py
+++ b/searx/engines/digbt.py
@@ -12,8 +12,7 @@
 
 from urllib.parse import urljoin
 from lxml import html
-from searx.engines.xpath import extract_text
-from searx.utils import get_torrent_size
+from searx.utils import extract_text, get_torrent_size
 
 
 categories = ['videos', 'music', 'files']
diff --git a/searx/engines/doku.py b/searx/engines/doku.py
index 513ffda89..e1b10d664 100644
--- a/searx/engines/doku.py
+++ b/searx/engines/doku.py
@@ -11,8 +11,7 @@
 
 from urllib.parse import urlencode
 from lxml.html import fromstring
-from searx.engines.xpath import extract_text
-from searx.utils import eval_xpath
+from searx.utils import extract_text, eval_xpath
 
 # engine dependent config
 categories = ['general']  # TODO , 'images', 'music', 'videos', 'files'
diff --git a/searx/engines/duckduckgo.py b/searx/engines/duckduckgo.py
index fb1ea2b2d..4a42fe7f1 100644
--- a/searx/engines/duckduckgo.py
+++ b/searx/engines/duckduckgo.py
@@ -16,9 +16,8 @@
 from lxml.html import fromstring
 from json import loads
 from urllib.parse import urlencode
-from searx.engines.xpath import extract_text
 from searx.poolrequests import get
-from searx.utils import match_language, eval_xpath
+from searx.utils import extract_text, match_language, eval_xpath
 
 # engine dependent config
 categories = ['general']
diff --git a/searx/engines/duckduckgo_definitions.py b/searx/engines/duckduckgo_definitions.py
index 73154a525..7ce54f056 100644
--- a/searx/engines/duckduckgo_definitions.py
+++ b/searx/engines/duckduckgo_definitions.py
@@ -13,9 +13,8 @@ import json
 from urllib.parse import urlencode
 from lxml import html
 from re import compile
-from searx.engines.xpath import extract_text
 from searx.engines.duckduckgo import _fetch_supported_languages, supported_languages_url, language_aliases
-from searx.utils import html_to_text, match_language
+from searx.utils import extract_text, html_to_text, match_language
 
 url = 'https://api.duckduckgo.com/'\
     + '?{query}&format=json&pretty=0&no_redirect=1&d=1'
diff --git a/searx/engines/duckduckgo_images.py b/searx/engines/duckduckgo_images.py
index 38e141f8b..27ef7442e 100644
--- a/searx/engines/duckduckgo_images.py
+++ b/searx/engines/duckduckgo_images.py
@@ -15,12 +15,12 @@
 
 from json import loads
 from urllib.parse import urlencode
-from searx.engines.xpath import extract_text
 from searx.engines.duckduckgo import (
     _fetch_supported_languages, supported_languages_url,
     get_region_code, language_aliases
 )
 from searx.poolrequests import get
+from searx.utils import extract_text
 
 # engine dependent config
 categories = ['images']
diff --git a/searx/engines/duden.py b/searx/engines/duden.py
index a711f422e..bbe11de9b 100644
--- a/searx/engines/duden.py
+++ b/searx/engines/duden.py
@@ -11,8 +11,7 @@
 from lxml import html, etree
 import re
 from urllib.parse import quote, urljoin
-from searx.engines.xpath import extract_text
-from searx.utils import eval_xpath
+from searx.utils import extract_text, eval_xpath
 from searx import logger
 
 categories = ['general']
diff --git a/searx/engines/etools.py b/searx/engines/etools.py
index efc102ef6..a0762d1c7 100644
--- a/searx/engines/etools.py
+++ b/searx/engines/etools.py
@@ -11,8 +11,7 @@
 
 from lxml import html
 from urllib.parse import quote
-from searx.engines.xpath import extract_text
-from searx.utils import eval_xpath
+from searx.utils import extract_text, eval_xpath
 
 categories = ['general']
 paging = False
diff --git a/searx/engines/fdroid.py b/searx/engines/fdroid.py
index a2a5114df..3d37db44e 100644
--- a/searx/engines/fdroid.py
+++ b/searx/engines/fdroid.py
@@ -11,7 +11,7 @@
 
 from urllib.parse import urlencode
 from lxml import html
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 # engine dependent config
 categories = ['files']
diff --git a/searx/engines/framalibre.py b/searx/engines/framalibre.py
index 14b659b5f..e3d056425 100644
--- a/searx/engines/framalibre.py
+++ b/searx/engines/framalibre.py
@@ -13,7 +13,7 @@
 from html import escape
 from urllib.parse import urljoin, urlencode
 from lxml import html
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 # engine dependent config
 categories = ['it']
diff --git a/searx/engines/gentoo.py b/searx/engines/gentoo.py
index b6bc99fab..16b3e692d 100644
--- a/searx/engines/gentoo.py
+++ b/searx/engines/gentoo.py
@@ -13,7 +13,7 @@
 
 from urllib.parse import urlencode, urljoin
 from lxml import html
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 # engine dependent config
 categories = ['it']
diff --git a/searx/engines/google.py b/searx/engines/google.py
index c9faadb6e..83b18a9a0 100644
--- a/searx/engines/google.py
+++ b/searx/engines/google.py
@@ -21,9 +21,8 @@ Definitions`_.
 from urllib.parse import urlencode, urlparse
 from lxml import html
 from flask_babel import gettext
-from searx.engines.xpath import extract_text
 from searx import logger
-from searx.utils import match_language, eval_xpath
+from searx.utils import match_language, extract_text, eval_xpath
 
 logger = logger.getChild('google engine')
 
diff --git a/searx/engines/google_images.py b/searx/engines/google_images.py
index 9dd5fad2c..8cfb1e17f 100644
--- a/searx/engines/google_images.py
+++ b/searx/engines/google_images.py
@@ -28,8 +28,7 @@ from urllib.parse import urlencode, urlparse, unquote
 from lxml import html
 from flask_babel import gettext
 from searx import logger
-from searx.utils import eval_xpath
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text, eval_xpath
 
 # pylint: disable=unused-import
 from searx.engines.google import (
diff --git a/searx/engines/google_videos.py b/searx/engines/google_videos.py
index 08af55902..78e1eb1cb 100644
--- a/searx/engines/google_videos.py
+++ b/searx/engines/google_videos.py
@@ -14,7 +14,7 @@ from datetime import date, timedelta
 from json import loads
 from urllib.parse import urlencode
 from lxml import html
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 import re
 
 # engine dependent config
diff --git a/searx/engines/ina.py b/searx/engines/ina.py
index cce580273..52c939498 100644
--- a/searx/engines/ina.py
+++ b/searx/engines/ina.py
@@ -16,7 +16,7 @@ from urllib.parse import urlencode
 from lxml import html
 from dateutil import parser
 from html.parser import HTMLParser
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 
 # engine dependent config
diff --git a/searx/engines/kickass.py b/searx/engines/kickass.py
index af48d990b..90bd33063 100644
--- a/searx/engines/kickass.py
+++ b/searx/engines/kickass.py
@@ -13,8 +13,7 @@
 from lxml import html
 from operator import itemgetter
 from urllib.parse import quote, urljoin
-from searx.engines.xpath import extract_text
-from searx.utils import get_torrent_size, convert_str_to_int
+from searx.utils import extract_text, get_torrent_size, convert_str_to_int
 
 # engine dependent config
 categories = ['videos', 'music', 'files']
diff --git a/searx/engines/nyaa.py b/searx/engines/nyaa.py
index ed8897ddc..e0a91494f 100644
--- a/searx/engines/nyaa.py
+++ b/searx/engines/nyaa.py
@@ -11,8 +11,7 @@
 
 from lxml import html
 from urllib.parse import urlencode
-from searx.engines.xpath import extract_text
-from searx.utils import get_torrent_size, int_or_zero
+from searx.utils import extract_text, get_torrent_size, int_or_zero
 
 # engine dependent config
 categories = ['files', 'images', 'videos', 'music']
diff --git a/searx/engines/piratebay.py b/searx/engines/piratebay.py
index 42866d058..b56b92a24 100644
--- a/searx/engines/piratebay.py
+++ b/searx/engines/piratebay.py
@@ -13,8 +13,7 @@ from datetime import datetime
 from operator import itemgetter
 
 from urllib.parse import quote, urljoin
-from searx.engines.xpath import extract_text
-from searx.utils import get_torrent_size
+from searx.utils import extract_text, get_torrent_size
 
 # engine dependent config
 categories = ["videos", "music", "files"]
diff --git a/searx/engines/seedpeer.py b/searx/engines/seedpeer.py
index 3778abe7b..39916da6e 100644
--- a/searx/engines/seedpeer.py
+++ b/searx/engines/seedpeer.py
@@ -12,7 +12,7 @@ from lxml import html
 from json import loads
 from operator import itemgetter
 from urllib.parse import quote, urljoin
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 
 url = 'https://seedpeer.me/'
diff --git a/searx/engines/stackoverflow.py b/searx/engines/stackoverflow.py
index 90e4543d7..c6d58de65 100644
--- a/searx/engines/stackoverflow.py
+++ b/searx/engines/stackoverflow.py
@@ -12,7 +12,7 @@
 
 from urllib.parse import urlencode, urljoin
 from lxml import html
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 # engine dependent config
 categories = ['it']
diff --git a/searx/engines/startpage.py b/searx/engines/startpage.py
index b6d0c24f7..d26c2d105 100644
--- a/searx/engines/startpage.py
+++ b/searx/engines/startpage.py
@@ -17,9 +17,8 @@ import re
 from unicodedata import normalize, combining
 from babel import Locale
 from babel.localedata import locale_identifiers
-from searx.engines.xpath import extract_text
 from searx.languages import language_codes
-from searx.utils import eval_xpath, match_language
+from searx.utils import extract_text, eval_xpath, match_language
 
 # engine dependent config
 categories = ['general']
diff --git a/searx/engines/tokyotoshokan.py b/searx/engines/tokyotoshokan.py
index 9c8774d7c..9fffba8a6 100644
--- a/searx/engines/tokyotoshokan.py
+++ b/searx/engines/tokyotoshokan.py
@@ -13,9 +13,8 @@
 import re
 from urllib.parse import urlencode
 from lxml import html
-from searx.engines.xpath import extract_text
 from datetime import datetime
-from searx.utils import get_torrent_size, int_or_zero
+from searx.utils import extract_text, get_torrent_size, int_or_zero
 
 # engine dependent config
 categories = ['files', 'videos', 'music']
diff --git a/searx/engines/torrentz.py b/searx/engines/torrentz.py
index fcc8c042c..4d3e6fdd7 100644
--- a/searx/engines/torrentz.py
+++ b/searx/engines/torrentz.py
@@ -15,8 +15,7 @@ import re
 from urllib.parse import urlencode
 from lxml import html
 from datetime import datetime
-from searx.engines.xpath import extract_text
-from searx.utils import get_torrent_size
+from searx.utils import extract_text, get_torrent_size
 
 # engine dependent config
 categories = ['files', 'videos', 'music']
diff --git a/searx/engines/twitter.py b/searx/engines/twitter.py
index 549b14e96..6d9bdbb5c 100644
--- a/searx/engines/twitter.py
+++ b/searx/engines/twitter.py
@@ -15,7 +15,7 @@
 from urllib.parse import urlencode, urljoin
 from lxml import html
 from datetime import datetime
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 # engine dependent config
 categories = ['social media']
diff --git a/searx/engines/wikidata.py b/searx/engines/wikidata.py
index ffa3724fd..c557f4e59 100644
--- a/searx/engines/wikidata.py
+++ b/searx/engines/wikidata.py
@@ -13,9 +13,8 @@
 
 from searx import logger
 from searx.poolrequests import get
-from searx.engines.xpath import extract_text
 from searx.engines.wikipedia import _fetch_supported_languages, supported_languages_url
-from searx.utils import match_language, eval_xpath
+from searx.utils import extract_text, match_language, eval_xpath
 
 from urllib.parse import urlencode
 from json import loads
diff --git a/searx/engines/www1x.py b/searx/engines/www1x.py
index 1cb74dbad..8d691c852 100644
--- a/searx/engines/www1x.py
+++ b/searx/engines/www1x.py
@@ -12,7 +12,7 @@
 
 from lxml import html
 from urllib.parse import urlencode, urljoin
-from searx.engines.xpath import extract_text
+from searx.utils import extract_text
 
 # engine dependent config
 categories = ['images']
diff --git a/searx/engines/xpath.py b/searx/engines/xpath.py
index bd97a93a5..a269253d7 100644
--- a/searx/engines/xpath.py
+++ b/searx/engines/xpath.py
@@ -1,7 +1,6 @@
-from urllib.parse import unquote, urlencode, urljoin, urlparse
 from lxml import html
-from lxml.etree import _ElementStringResult, _ElementUnicodeResult
-from searx.utils import html_to_text, eval_xpath
+from urllib.parse import urlencode
+from searx.utils import extract_text, extract_url, eval_xpath
 
 search_url = None
 url_xpath = None
@@ -21,76 +20,6 @@ page_size = 1
 first_page_num = 1
 
 
-'''
-if xpath_results is list, extract the text from each result and concat the list
-if xpath_results is a xml element, extract all the text node from it
-   ( text_content() method from lxml )
-if xpath_results is a string element, then it's already done
-'''
-
-
-def extract_text(xpath_results):
-    if type(xpath_results) == list:
-        # it's list of result : concat everything using recursive call
-        result = ''
-        for e in xpath_results:
-            result = result + extract_text(e)
-        return result.strip()
-    elif type(xpath_results) in [_ElementStringResult, _ElementUnicodeResult]:
-        # it's a string
-        return ''.join(xpath_results)
-    else:
-        # it's a element
-        text = html.tostring(
-            xpath_results, encoding='unicode', method='text', with_tail=False
-        )
-        text = text.strip().replace('\n', ' ')
-        return ' '.join(text.split())
-
-
-def extract_url(xpath_results, search_url):
-    if xpath_results == []:
-        raise Exception('Empty url resultset')
-    url = extract_text(xpath_results)
-
-    if url.startswith('//'):
-        # add http or https to this kind of url //example.com/
-        parsed_search_url = urlparse(search_url)
-        url = '{0}:{1}'.format(parsed_search_url.scheme or 'http', url)
-    elif url.startswith('/'):
-        # fix relative url to the search engine
-        url = urljoin(search_url, url)
-
-    # fix relative urls that fall through the crack
-    if '://' not in url:
-        url = urljoin(search_url, url)
-
-    # normalize url
-    url = normalize_url(url)
-
-    return url
-
-
-def normalize_url(url):
-    parsed_url = urlparse(url)
-
-    # add a / at this end of the url if there is no path
-    if not parsed_url.netloc:
-        raise Exception('Cannot parse url')
-    if not parsed_url.path:
-        url += '/'
-
-    # FIXME : hack for yahoo
-    if parsed_url.hostname == 'search.yahoo.com'\
-       and parsed_url.path.startswith('/r'):
-        p = parsed_url.path
-        mark = p.find('/**')
-        if mark != -1:
-            return unquote(p[mark + 3:]).decode()
-
-    return url
-
-
 def request(query, params):
     query = urlencode({'q': query})[2:]
 
diff --git a/searx/engines/yahoo.py b/searx/engines/yahoo.py
index 0133b57b5..3420aa6d5 100644
--- a/searx/engines/yahoo.py
+++ b/searx/engines/yahoo.py
@@ -13,8 +13,7 @@
 
 from urllib.parse import unquote, urlencode
 from lxml import html
-from searx.engines.xpath import extract_text, extract_url
-from searx.utils import match_language, eval_xpath
+from searx.utils import extract_text, extract_url, match_language, eval_xpath
 
 # engine dependent config
 categories = ['general']
diff --git a/searx/engines/yahoo_news.py b/searx/engines/yahoo_news.py
index 345e4d91f..e9dd5d6db 100644
--- a/searx/engines/yahoo_news.py
+++ b/searx/engines/yahoo_news.py
@@ -13,12 +13,11 @@ import re
 from datetime import datetime, timedelta
 from urllib.parse import urlencode
 from lxml import html
-from searx.engines.xpath import extract_text, extract_url
 from searx.engines.yahoo import (
     parse_url, _fetch_supported_languages, supported_languages_url, language_aliases
 )
 from dateutil import parser
-from searx.utils import match_language
+from searx.utils import extract_text, extract_url, match_language
 
 # engine dependent config
 categories = ['news']
diff --git a/searx/engines/yggtorrent.py b/searx/engines/yggtorrent.py
index 37bf3b1d9..ec84d2c6b 100644
--- a/searx/engines/yggtorrent.py
+++ b/searx/engines/yggtorrent.py
@@ -12,8 +12,7 @@ from lxml import html
 from operator import itemgetter
 from datetime import datetime
 from urllib.parse import quote
-from searx.engines.xpath import extract_text
-from searx.utils import get_torrent_size
+from searx.utils import extract_text, get_torrent_size
 from searx.poolrequests import get as http_get
 
 # engine dependent config
diff --git a/searx/engines/youtube_noapi.py b/searx/engines/youtube_noapi.py
index fef501458..16c0eddeb 100644
--- a/searx/engines/youtube_noapi.py
+++ b/searx/engines/youtube_noapi.py
@@ -11,8 +11,7 @@
 from functools import reduce
 from json import loads
 from urllib.parse import quote_plus
-from searx.engines.xpath import extract_text
-from searx.utils import list_get
+from searx.utils import extract_text, list_get
 
 # engine dependent config
 categories = ['videos', 'music']
diff --git a/searx/utils.py b/searx/utils.py
index f74f2ac88..0be3c5b00 100644
--- a/searx/utils.py
+++ b/searx/utils.py
@@ -10,9 +10,13 @@ from os.path import splitext, join
 from io import open
 from random import choice
 from html.parser import HTMLParser
-from lxml.etree import XPath
+from urllib.parse import urljoin, urlparse, unquote
+
+from lxml import html
+from lxml.etree import XPath, _ElementStringResult, _ElementUnicodeResult
 from babel.core import get_global
 
+
 from searx import settings
 from searx.version import VERSION_STRING
 from searx.languages import language_codes
@@ -35,12 +39,17 @@ lang_to_lc_cache = dict()
 
 
 def searx_useragent():
+    """Return the searx User Agent"""
     return 'searx/{searx_version} {suffix}'.format(
            searx_version=VERSION_STRING,
            suffix=settings['outgoing'].get('useragent_suffix', ''))
 
 
 def gen_useragent(os=None):
+    """Return a random browser User Agent
+
+    See searx/data/useragents.json
+    """
     return str(useragents['ua'].format(os=os or choice(useragents['os']), version=choice(useragents['versions'])))
 
 
@@ -95,18 +104,156 @@ class HTMLTextExtractor(HTMLParser):
         return ''.join(self.result).strip()
 
 
-def html_to_text(html):
-    html = html.replace('\n', ' ')
-    html = ' '.join(html.split())
+def html_to_text(html_str):
+    """Extract text from a HTML string
+
+    Args:
+        * html_str (str): string HTML
+
+    Returns:
+        * str: extracted text
+
+    Examples:
+        >>> html_to_text('Example <span id="42">#2</span>')
+        'Example #2'
+
+        >>> html_to_text('<style>.span { color: red; }</style><span>Example</span>')
+        'Example'
+    """
+    html_str = html_str.replace('\n', ' ')
+    html_str = ' '.join(html_str.split())
     s = HTMLTextExtractor()
     try:
-        s.feed(html)
+        s.feed(html_str)
     except HTMLTextExtractorException:
-        logger.debug("HTMLTextExtractor: invalid HTML\n%s", html)
+        logger.debug("HTMLTextExtractor: invalid HTML\n%s", html_str)
     return s.get_text()
 
 
+def extract_text(xpath_results):
+    """Extract text from a lxml result
+
+      * if xpath_results is list, extract the text from each result and concat the list
+      * if xpath_results is a xml element, extract all the text node from it
+        ( text_content() method from lxml )
+      * if xpath_results is a string element, then it's already done
+    """
+    if type(xpath_results) == list:
+        # it's list of result : concat everything using recursive call
+        result = ''
+        for e in xpath_results:
+            result = result + extract_text(e)
+        return result.strip()
+    elif type(xpath_results) in [_ElementStringResult, _ElementUnicodeResult]:
+        # it's a string
+        return ''.join(xpath_results)
+    else:
+        # it's a element
+        text = html.tostring(
+            xpath_results, encoding='unicode', method='text', with_tail=False
+        )
+        text = text.strip().replace('\n', ' ')
+        return ' '.join(text.split())
+
+
+def normalize_url(url, base_url):
+    """Normalize URL: add protocol, join URL with base_url, add trailing slash if there is no path
+
+    Args:
+        * url (str): Relative URL
+        * base_url (str): Base URL, it must be an absolute URL.
+
+    Example:
+        >>> normalize_url('https://example.com', 'http://example.com/')
+        'https://example.com/'
+        >>> normalize_url('//example.com', 'http://example.com/')
+        'http://example.com/'
+        >>> normalize_url('//example.com', 'https://example.com/')
+        'https://example.com/'
+        >>> normalize_url('/path?a=1', 'https://example.com')
+        'https://example.com/path?a=1'
+        >>> normalize_url('', 'https://example.com')
+        'https://example.com/'
+        >>> normalize_url('/test', '/path')
+        raise Exception
+
+    Raises:
+        * lxml.etree.ParserError
+
+    Returns:
+        * str: normalized URL
+    """
+    if url.startswith('//'):
+        # add http or https to this kind of url //example.com/
+        parsed_search_url = urlparse(base_url)
+        url = '{0}:{1}'.format(parsed_search_url.scheme or 'http', url)
+    elif url.startswith('/'):
+        # fix relative url to the search engine
+        url = urljoin(base_url, url)
+
+    # fix relative urls that fall through the crack
+    if '://' not in url:
+        url = urljoin(base_url, url)
+
+    parsed_url = urlparse(url)
+
+    # add a / at this end of the url if there is no path
+    if not parsed_url.netloc:
+        raise Exception('Cannot parse url')
+    if not parsed_url.path:
+        url += '/'
+
+    return url
+
+
+def extract_url(xpath_results, base_url):
+    """Extract and normalize URL from lxml Element
+
+    Args:
+        * xpath_results (Union[List[html.HtmlElement], html.HtmlElement]): lxml Element(s)
+        * base_url (str): Base URL
+
+    Example:
+        >>> def f(s, search_url):
+        >>>    return searx.utils.extract_url(html.fromstring(s), search_url)
+        >>> f('<span id="42">https://example.com</span>', 'http://example.com/')
+        'https://example.com/'
+        >>> f('https://example.com', 'http://example.com/')
+        'https://example.com/'
+        >>> f('//example.com', 'http://example.com/')
+        'http://example.com/'
+        >>> f('//example.com', 'https://example.com/')
+        'https://example.com/'
+        >>> f('/path?a=1', 'https://example.com')
+        'https://example.com/path?a=1'
+        >>> f('', 'https://example.com')
+        raise lxml.etree.ParserError
+        >>> searx.utils.extract_url([], 'https://example.com')
+        raise Exception
+
+    Raises:
+        * Exception
+        * lxml.etree.ParserError
+
+    Returns:
+        * str: normalized URL
+    """
+    if xpath_results == []:
+        raise Exception('Empty url resultset')
+
+    url = extract_text(xpath_results)
+    return normalize_url(url, base_url)
+
+
 def dict_subset(d, properties):
+    """Extract a subset of a dict
+
+    Examples:
+        >>> dict_subset({'A': 'a', 'B': 'b', 'C': 'c'}, ['A', 'C'])
+        {'A': 'a', 'C': 'c'}
+        >>> >> dict_subset({'A': 'a', 'B': 'b', 'C': 'c'}, ['A', 'D'])
+        {'A': 'a'}
+    """
     result = {}
     for k in properties:
         if k in d:
@@ -114,8 +261,19 @@ def dict_subset(d, properties):
     return result
 
 
-# get element in list or default value
 def list_get(a_list, index, default=None):
+    """Get element in list or default value
+
+    Examples:
+        >>> list_get(['A', 'B', 'C'], 0)
+        'A'
+        >>> list_get(['A', 'B', 'C'], 3)
+        None
+        >>> list_get(['A', 'B', 'C'], 3, 'default')
+        'default'
+        >>> list_get(['A', 'B', 'C'], -1)
+        'C'
+    """
     if len(a_list) > index:
         return a_list[index]
     else:
@@ -123,6 +281,21 @@ def list_get(a_list, index, default=None):
 
 
 def get_torrent_size(filesize, filesize_multiplier):
+    """
+
+    Args:
+        * filesize (str): size
+        * filesize_multiplier (str): TB, GB, .... TiB, GiB...
+
+    Returns:
+        * int: number of bytes
+
+    Example:
+        >>> get_torrent_size('5', 'GB')
+        5368709120
+        >>> get_torrent_size('3.14', 'MiB')
+        3140000
+    """
     try:
         filesize = float(filesize)
 
@@ -149,14 +322,18 @@ def get_torrent_size(filesize, filesize_multiplier):
 
 
 def convert_str_to_int(number_str):
+    """Convert number_str to int or 0 if number_str is not a number."""
     if number_str.isdigit():
         return int(number_str)
     else:
         return 0
 
 
-# convert a variable to integer or return 0 if it's not a number
 def int_or_zero(num):
+    """Convert num to int or 0. num can be either a str or a list.
+    If num is a list, the first element is converted to int (or return 0 if the list is empty).
+    If num is a str, see convert_str_to_int
+    """
     if isinstance(num, list):
         if len(num) < 1:
             return 0
@@ -165,6 +342,22 @@ def int_or_zero(num):
 
 
 def is_valid_lang(lang):
+    """Return language code and name if lang describe a language.
+
+    Examples:
+        >>> is_valid_lang('zz')
+        False
+        >>> is_valid_lang('uk')
+        (True, 'uk', 'ukrainian')
+        >>> is_valid_lang(b'uk')
+        (True, 'uk', 'ukrainian')
+        >>> is_valid_lang('en')
+        (True, 'en', 'english')
+        >>> searx.utils.is_valid_lang('Español')
+        (True, 'es', 'spanish')
+        >>> searx.utils.is_valid_lang('Spanish')
+        (True, 'es', 'spanish')
+    """
     if isinstance(lang, bytes):
         lang = lang.decode()
     is_abbr = (len(lang) == 2)
@@ -192,8 +385,8 @@ def _get_lang_to_lc_dict(lang_list):
     return value
 
 
-# auxiliary function to match lang_code in lang_list
 def _match_language(lang_code, lang_list=[], custom_aliases={}):
+    """auxiliary function to match lang_code in lang_list"""
     # replace language code with a custom alias if necessary
     if lang_code in custom_aliases:
         lang_code = custom_aliases[lang_code]
@@ -215,8 +408,8 @@ def _match_language(lang_code, lang_list=[], custom_aliases={}):
     return _get_lang_to_lc_dict(lang_list).get(lang_code, None)
 
 
-# get the language code from lang_list that best matches locale_code
 def match_language(locale_code, lang_list=[], custom_aliases={}, fallback='en-US'):
+    """get the language code from lang_list that best matches locale_code"""
     # try to get language from given locale_code
     language = _match_language(locale_code, lang_list, custom_aliases)
     if language:
@@ -258,6 +451,7 @@ def load_module(filename, module_dir):
 
 
 def to_string(obj):
+    """Convert obj to its string representation."""
     if isinstance(obj, str):
         return obj
     if isinstance(obj, Number):
@@ -269,13 +463,19 @@ def to_string(obj):
 
 
 def ecma_unescape(s):
-    """
-    python implementation of the unescape javascript function
+    """Python implementation of the unescape javascript function
 
     https://www.ecma-international.org/ecma-262/6.0/#sec-unescape-string
     https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Objets_globaux/unescape
+
+    Examples:
+        >>> ecma_unescape('%u5409')
+        '吉'
+        >>> ecma_unescape('%20')
+        ' '
+        >>> ecma_unescape('%F3')
+        'ó'
     """
-    # s = unicode(s)
     # "%u5409" becomes "吉"
     s = ecma_unescape4_re.sub(lambda e: chr(int(e.group(1), 16)), s)
     # "%20" becomes " ", "%F3" becomes "ó"
@@ -299,6 +499,11 @@ def get_engine_from_settings(name):
 
 
 def get_xpath(xpath_str):
+    """Return cached compiled XPath
+
+    There is no thread lock.
+    Worst case scenario, xpath_str is compiled more than one time.
+    """
     result = xpath_cache.get(xpath_str, None)
     if result is None:
         result = XPath(xpath_str)
@@ -307,5 +512,6 @@ def get_xpath(xpath_str):
 
 
 def eval_xpath(element, xpath_str):
+    """Equivalent of element.xpath(xpath_str) but compile xpath_str once for all."""
     xpath = get_xpath(xpath_str)
     return xpath(element)
diff --git a/tests/unit/test_utils.py b/tests/unit/test_utils.py
index 69f5ef92a..f3a98ad71 100644
--- a/tests/unit/test_utils.py
+++ b/tests/unit/test_utils.py
@@ -1,4 +1,7 @@
 # -*- coding: utf-8 -*-
+import lxml.etree
+from lxml import html
+
 from searx.testing import SearxTestCase
 from searx import utils
 
@@ -16,7 +19,30 @@ class TestUtils(SearxTestCase):
         self.assertTrue(utils.searx_useragent().startswith('searx'))
 
     def test_html_to_text(self):
-        html = """
+        html_str = """
+        <a href="/testlink" class="link_access_account">
+            <style>
+                .toto {
+                    color: red;
+                }
+            </style>
+            <span class="toto">
+                <span>
+                    <img src="test.jpg" />
+                </span>
+            </span>
+            <span class="titi">
+                            Test text
+            </span>
+            <script>value='dummy';</script>
+        </a>
+        """
+        self.assertIsInstance(utils.html_to_text(html_str), str)
+        self.assertIsNotNone(utils.html_to_text(html_str))
+        self.assertEqual(utils.html_to_text(html_str), "Test text")
+
+    def test_extract_text(self):
+        html_str = """
         <a href="/testlink" class="link_access_account">
             <span class="toto">
                 <span>
@@ -28,9 +54,24 @@ class TestUtils(SearxTestCase):
             </span>
         </a>
         """
-        self.assertIsInstance(utils.html_to_text(html), str)
-        self.assertIsNotNone(utils.html_to_text(html))
-        self.assertEqual(utils.html_to_text(html), "Test text")
+        dom = html.fromstring(html_str)
+        self.assertEqual(utils.extract_text(dom), 'Test text')
+        self.assertEqual(utils.extract_text(dom.xpath('//span')), 'Test text')
+        self.assertEqual(utils.extract_text(dom.xpath('//img/@src')), 'test.jpg')
+        self.assertEqual(utils.extract_text(dom.xpath('//unexistingtag')), '')
+
+    def test_extract_url(self):
+        def f(html_str, search_url):
+            return utils.extract_url(html.fromstring(html_str), search_url)
+        self.assertEqual(f('<span id="42">https://example.com</span>', 'http://example.com/'), 'https://example.com/')
+        self.assertEqual(f('https://example.com', 'http://example.com/'), 'https://example.com/')
+        self.assertEqual(f('//example.com', 'http://example.com/'), 'http://example.com/')
+        self.assertEqual(f('//example.com', 'https://example.com/'), 'https://example.com/')
+        self.assertEqual(f('/path?a=1', 'https://example.com'), 'https://example.com/path?a=1')
+        with self.assertRaises(lxml.etree.ParserError):
+            f('', 'https://example.com')
+        with self.assertRaises(Exception):
+            utils.extract_url([], 'https://example.com')
 
     def test_html_to_text_invalid(self):
         html = '<p><b>Lorem ipsum</i>dolor sit amet</p>'