fix key rotation without state reset (#8)

Author: NostraDavid

src/bitvavo_client/transport/http.py

@@ -70,13 +70,19 @@ def select_key(self, index: int) -> None:
 
     def _rotate_key(self) -> bool:
         """Rotate to the next configured API key if available."""
-        if not self._keys:
+        if len(self._keys) <= 1:
             return False
+
         next_idx = (self.key_index + 1) % len(self._keys)
         now = int(time.time() * 1000)
-        if now < self.rate_limiter.get_reset_at(next_idx):
+        reset_at = self.rate_limiter.get_reset_at(next_idx)
+
+        if now < reset_at:
             self.rate_limiter.sleep_until_reset(next_idx)
-        self.rate_limiter.reset_key(next_idx)
+            self.rate_limiter.reset_key(next_idx)
+        elif self.rate_limiter.get_remaining(next_idx) <= self.rate_limiter.buffer:
+            self.rate_limiter.reset_key(next_idx)
+
         self.select_key(next_idx)
         return True
 

tests/bitvavo_client/transport/test_http.py

@@ -160,3 +160,39 @@ def has_budget(idx: int, weight: int) -> bool:
 
     assert isinstance(result, Success)
     assert client.key_index == 1
+
+
+def test_rotate_key_does_not_reset_when_budget_available(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Rotation should not reset key state if the key still has budget."""
+    settings = BitvavoSettings(
+        api_keys=[{"key": "k1", "secret": "s1"}, {"key": "k2", "secret": "s2"}],
+    )
+    manager = RateLimitManager(settings.default_rate_limit, settings.rate_limit_buffer)
+    client = HTTPClient(settings, manager)
+
+    manager.state[1]["remaining"] = 500
+    manager.state[1]["resetAt"] = 0
+
+    with patch.object(manager, "reset_key") as mock_reset:
+        client._rotate_key()  # noqa: SLF001
+
+    assert client.key_index == 1
+    mock_reset.assert_not_called()
+
+
+def test_rotate_key_resets_expired_key(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Rotation should reset key if its budget is exhausted and reset time passed."""
+    settings = BitvavoSettings(
+        api_keys=[{"key": "k1", "secret": "s1"}, {"key": "k2", "secret": "s2"}],
+    )
+    manager = RateLimitManager(settings.default_rate_limit, settings.rate_limit_buffer)
+    client = HTTPClient(settings, manager)
+
+    manager.state[1]["remaining"] = 0
+    manager.state[1]["resetAt"] = 0
+
+    with patch.object(manager, "reset_key") as mock_reset, patch("time.time", return_value=1):
+        client._rotate_key()  # noqa: SLF001
+
+    assert client.key_index == 1
+    mock_reset.assert_called_once_with(1)