Make mirror tests bandwidth agnostic.

polycotylus/_mirror.py

@@ -292,7 +292,7 @@ def _download(self):
             with self.upstream:
                 with open(cache, "wb") as f:
                     shutil.copyfileobj(self.upstream, f)
-        except:  # pragma: no cover
+        except:
             with contextlib.suppress(FileNotFoundError):
                 cache.unlink()
             raise

tests/test_mirror.py

@@ -9,6 +9,9 @@
 from pathlib import Path
 import sys
 import subprocess
+import contextlib
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+from http import HTTPStatus
 
 import pytest
 
@@ -29,6 +32,23 @@ def _alpine_mirror(tmp_path):
     )
 
 
+@contextlib.contextmanager
+def fake_upstream(do_GET):
+
+    class RequestHandler(BaseHTTPRequestHandler):
+        pass
+
+    RequestHandler.do_GET = do_GET
+
+    with ThreadingHTTPServer(("", 8899), RequestHandler) as httpd:
+        try:
+            thread = threading.Thread(target=httpd.serve_forever)
+            thread.start()
+            yield
+        finally:
+            httpd.shutdown()
+
+
 def test_basic(tmp_path):
     self = _alpine_mirror(tmp_path)
     url = "http://localhost:9989/MIRRORS.txt"
@@ -160,17 +180,29 @@ def test_index_page_handling(tmp_path):
 
 
 def test_concurrent(tmp_path):
-    self = _alpine_mirror(tmp_path)
-    url = "http://localhost:9989/edge/main/x86_64/APKINDEX.tar.gz"
-
-    with self:
-        for i in range(3):
-            with urlopen(url) as a:
-                part = a.read(100)
-                with urlopen(url) as b:
-                    raw = b.read()
-                    gzip.decompress(raw)
-                gzip.decompress(part + a.read())
+    url = "http://localhost:9989/foo.bar"
+    self = CachedMirror(
+        "http://0.0.0.0:8899", tmp_path, ["*.bar"], [], 9989, "", (_alpine_sync_time,))
+    payload = os.urandom(300_000)
+
+    def upstream_get(self):
+        self.send_response(HTTPStatus.OK)
+        self.send_header("Content-Length", 300_000)
+        self.end_headers()
+        for i in range(0, 300_000, 100):
+            # Mimic a slow download rate.
+            self.wfile.write(payload[i: i + 100])
+            time.sleep(0.001)
+
+    with fake_upstream(upstream_get):
+        with self:
+            for i in range(3):
+                with urlopen(url) as a:
+                    part = a.read(100)
+                    with urlopen(url) as b:
+                        raw = b.read()
+                        assert raw == payload
+                    assert part + a.read() == payload
 
 
 def test_kill_resume(tmp_path):