Add tests and test-strategies for custom "implements" requirements

tests/strategy/strats/broken_strats/broken_futures_strategies.py

@@ -0,0 +1,16 @@
+# The strategy which fails to load due to non-existent dependency
+
+from pandas import DataFrame
+
+from freqtrade.strategy.interface import IStrategy
+
+
+class TestStrategyNoImplements(IStrategy):
+
+    def populate_indicators(self, dataframe: DataFrame, metadata: dict) -> DataFrame:
+        return super().populate_indicators(dataframe, metadata)
+
+
+class TestStrategyNoImplementSell(TestStrategyNoImplements):
+    def populate_entry_trend(self, dataframe: DataFrame, metadata: dict) -> DataFrame:
+        return super().populate_entry_trend(dataframe, metadata)