Add test for new warning modes

tests/plugins/test_pairlist.py

@@ -2390,3 +2390,65 @@ def test_MarketCapPairList_exceptions(mocker, default_conf_usdt):
         OperationalException, match="This filter only support marketcap rank up to 250."
     ):
         PairListManager(exchange, default_conf_usdt)
+
+
+@pytest.mark.parametrize(
+    "pairlists,expected_error,expected_warning",
+    [
+        (
+            [{"method": "StaticPairList"}],
+            None,  # Error
+            None,  # Warning
+        ),
+        (
+            [{"method": "VolumePairList", "number_assets": 10}],
+            "VolumePairList",  # Error
+            None,  # Warning
+        ),
+        (
+            [{"method": "MarketCapPairList", "number_assets": 10}],
+            None,  # Error
+            r"MarketCapPairList.*lookahead.*",  # Warning
+        ),
+        (
+            [{"method": "StaticPairList"}, {"method": "FullTradesFilter"}],
+            None,  # Error
+            r"FullTradesFilter do not generate.*",  # Warning
+        ),
+        (  # combi, fails and warns
+            [
+                {"method": "VolumePairList", "number_assets": 10},
+                {"method": "MarketCapPairList", "number_assets": 10},
+            ],
+            "VolumePairList",  # Error
+            r"MarketCapPairList.*lookahead.*",  # Warning
+        ),
+    ],
+)
+def test_backtesting_modes(
+    mocker, default_conf_usdt, pairlists, expected_error, expected_warning, caplog, markets, tickers
+):
+    default_conf_usdt["runmode"] = "dry_run"
+    default_conf_usdt["pairlists"] = pairlists
+
+    mocker.patch.multiple(
+        EXMS,
+        markets=PropertyMock(return_value=markets),
+        exchange_has=MagicMock(return_value=True),
+        get_tickers=tickers,
+    )
+    exchange = get_patched_exchange(mocker, default_conf_usdt)
+
+    # Dry run mode - works always
+    PairListManager(exchange, default_conf_usdt)
+
+    default_conf_usdt["runmode"] = "backtest"
+    if expected_error:
+        with pytest.raises(OperationalException, match=f"Pairlist Handlers {expected_error}.*"):
+            PairListManager(exchange, default_conf_usdt)
+
+    if not expected_error:
+        PairListManager(exchange, default_conf_usdt)
+
+    if expected_warning:
+        assert log_has_re(f"Pairlist Handlers {expected_warning}", caplog)