Meta: Make import-wpt-test.py use html.parser, not BeautifulSoup

This change switches the Meta/import-wpt-test.py script to using the
standard html.parser module rather than BeautifulSoup.

Otherwise, without this change, when a contributor first tries to run
the script, if they don’t have BeautifulSoup installed, it will fail.

Note that this patch also includes an unrelated small change that
switches to using os.path.normpath — rather than Path.absolute() — to
“normalize” the destination names of the downloaded test files.

(cherry picked from commit 286511c4cf9dcd985882c9bbb2de42b01e7494a9)

Meta/import-wpt-test.py

@@ -2,8 +2,9 @@
 
 import os
 import sys
+
+from html.parser import HTMLParser
 from pathlib import Path
-from bs4 import BeautifulSoup
 from urllib.parse import urljoin
 from urllib.request import urlopen
 from collections import namedtuple
@@ -13,18 +14,16 @@
 wpt_expected_path = 'Tests/LibWeb/Text/expected/wpt-import'
 PathMapping = namedtuple('PathMapping', ['source', 'destination'])
 
+src_values = []
 
-def get_script_sources(page_source):
-    # Find all the <script> tags
-    scripts = [script for script in page_source.findAll('script')]
-
-    # Get the src attribute of each script tag
-    sources = list(map(lambda x: x.get('src'), scripts))
 
-    # Remove None values
-    sources = list(filter(lambda x: x is not None, sources))
+class ScriptSrcValueFinder(HTMLParser):
 
-    return sources
+    def handle_starttag(self, tag, attrs):
+        if tag == "script":
+            attr_dict = dict(attrs)
+            if "src" in attr_dict:
+                src_values.append(attr_dict["src"])
 
 
 def map_to_path(sources, is_resource=True, resource_path=None):
@@ -65,25 +64,23 @@ def modify_sources(files):
         parent_folder_path = '../' * parent_folder_count
 
         with open(file, 'r') as f:
-            page_source = BeautifulSoup(f.read(), 'html.parser')
-
-            # Iterate all scripts and overwrite the src attribute
-            scripts = [script for script in page_source.findAll('script')]
-            for script in scripts:
-                if script.get('src') is not None:
-                    if script['src'].startswith('/'):
-                        script['src'] = parent_folder_path + script['src'][1::]
+            page_source = f.read()
 
-            with open(file, 'w') as f:
-                f.write(str(page_source))
+        # Iterate all scripts and overwrite the src attribute
+        for i, src_value in enumerate(src_values):
+            if src_value.startswith('/'):
+                new_src_value = parent_folder_path + src_value[1::]
+                page_source = page_source.replace(src_value, new_src_value)
+                with open(file, 'w') as f:
+                    f.write(str(page_source))
 
 
 def download_files(filepaths):
     downloaded_files = []
 
     for file in filepaths:
         source = urljoin(file.source, "/".join(file.source.split('/')[3:]))
-        destination = Path(file.destination).absolute()
+        destination = Path(os.path.normpath(file.destination))
 
         if destination.exists():
             print(f"Skipping {destination} as it already exists")
@@ -132,13 +129,15 @@ def main():
     main_paths = map_to_path(main_file, False)
     files_to_modify = download_files(main_paths)
     create_expectation_files(main_paths)
-    modify_sources(files_to_modify)
 
-    page = urlopen(url_to_import)
-    page_source = BeautifulSoup(page, 'html.parser')
+    with urlopen(url_to_import) as response:
+        page = response.read().decode("utf-8")
+
+    parser = ScriptSrcValueFinder()
+    parser.feed(page)
 
-    scripts = get_script_sources(page_source)
-    script_paths = map_to_path(scripts, True, resource_path)
+    modify_sources(files_to_modify)
+    script_paths = map_to_path(src_values, True, resource_path)
     download_files(script_paths)