backend/scraper: Have collect() ignore None results

If a parser function returned None we yield it regardless, even though
it won't have any impact further down the line. Instead clean up the
collect() stream as early as possible.

1 files changed, 15 insertions, 0 deletions

diff --git a/tests/scrapers/test_scraper.py b/tests/scrapers/test_scraper.py
index 6f6f29d..8492425 100644
--- a/tests/scrapers/test_scraper.py
+++ b/tests/scrapers/test_scraper.py
@@ -9,6 +9,14 @@ class MockScraper(Scraper):
         yield "bar"
 
 
+class NoneScraper(Scraper):
+    is_available = True
+
+    def scrape(self):
+        yield lambda: "foo"
+        yield None
+
+
 class WarningScraper(Scraper):
     is_available = True
 
@@ -53,3 +61,10 @@ def test_scraper_collects_literal():
     generator = scraper.collect()
 
     assert set(generator) == set(["literal"])
+
+
+def test_scraper_collect_ignores_none():
+    scraper = NoneScraper(None)
+    generator = scraper.collect()
+
+    assert set(generator) == set(["foo"])