test(core): cover session pool growth, DRM locks, playlist encoding, and hybrid L6

tests/core/test_session_pool.py

@@ -0,0 +1,62 @@
+"""Unit tests for grow_session_pool, which enlarges a shared requests session's
+connection pool before download threads start. The tests open no sockets and check
+only the adapter mounts."""
+
+from __future__ import annotations
+
+import pytest
+import requests
+from requests.adapters import HTTPAdapter
+
+from unshackle.core.service import TimeoutHTTPAdapter, grow_session_pool
+
+pytestmark = pytest.mark.unit
+
+
+class FakeRnetSession:
+    """Stands in for RnetSession, which is not a requests.Session, so grow_session_pool skips it."""
+
+    def get_adapter(self, url: str) -> None:
+        raise AssertionError("grow_session_pool must not touch a non-requests session")
+
+
+def test_small_pool_is_remounted_on_both_schemes() -> None:
+    session = requests.Session()
+    old = session.get_adapter("https://x")
+    assert old._pool_maxsize < 64
+
+    grow_session_pool(session, 64)
+
+    https = session.get_adapter("https://x")
+    http = session.get_adapter("http://x")
+    assert isinstance(https, TimeoutHTTPAdapter)
+    assert https is http
+    assert https is not old
+    assert https._pool_maxsize == 64
+    assert https._pool_block is True
+    assert https.max_retries is old.max_retries
+
+
+def test_large_enough_pool_is_left_alone() -> None:
+    session = requests.Session()
+    session.mount("https://", HTTPAdapter(pool_connections=64, pool_maxsize=64))
+    old = session.get_adapter("https://x")
+
+    grow_session_pool(session, 64)
+
+    assert session.get_adapter("https://x") is old
+
+
+def test_equal_size_pool_is_left_alone() -> None:
+    session = requests.Session()
+    session.mount("https://", HTTPAdapter(pool_maxsize=32))
+    old = session.get_adapter("https://x")
+
+    grow_session_pool(session, 32)
+
+    assert session.get_adapter("https://x") is old
+
+
+@pytest.mark.parametrize("session", [object(), FakeRnetSession()])
+def test_non_requests_session_is_ignored(session: object) -> None:
+    grow_session_pool(session, 64)