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.

2 files changed, 21 insertions, 3 deletions

diff --git a/src/hircine/scraper/__init__.py b/src/hircine/scraper/__init__.py
index bc83436..4606f4a 100644
--- a/src/hircine/scraper/__init__.py
+++ b/src/hircine/scraper/__init__.py
@@ -86,13 +86,16 @@ class Scraper(ABC):
             transformers = []
 
         def generator():
-            for result in self.scrape():
-                if callable(result):
+            for item in self.scrape():
+                if callable(item):
                     try:
-                        yield result()
+                        result = item()
                     except ScrapeWarning as e:
                         self.log_warning(e)
                 else:
+                    result = item
+
+                if result is not None:
                     yield result
 
         gen = generator()
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"])