diff --git a/src/timeseriesflattener/test_aggregators.py b/src/timeseriesflattener/test_aggregators.py
index 89cfa9b1..ee7ad1ea 100644
--- a/src/timeseriesflattener/test_aggregators.py
+++ b/src/timeseriesflattener/test_aggregators.py
@@ -42,6 +42,7 @@ class SingleVarAggregatorExample:
     aggregator: Aggregator
     input_values: Sequence[float | None]
     expected_output_values: Sequence[float]
+    fallback_str: str = "nan"
 
     @property
     def input_frame(self) -> pl.LazyFrame:
@@ -58,7 +59,7 @@ def expected_output(self) -> pl.DataFrame:
         return pl.DataFrame(
             {
                 "prediction_time_uuid": [1],
-                f"value_{self.aggregator.name}_fallback_nan": self.expected_output_values,
+                f"value_{self.aggregator.name}_fallback_{self.fallback_str}": self.expected_output_values,
             }
         )
 
@@ -90,12 +91,13 @@ def expected_output(self) -> pl.DataFrame:
             aggregator=VarianceAggregator(), input_values=[1, 2], expected_output_values=[0.5]
         ),
         SingleVarAggregatorExample(
-            aggregator=HasValuesAggregator(), input_values=[1, 2], expected_output_values=[1]
+            aggregator=HasValuesAggregator(), input_values=[1, 2], expected_output_values=[1], fallback_str="False"
         ),
         SingleVarAggregatorExample(
             aggregator=HasValuesAggregator(),
             input_values=[None],  # type: ignore
             expected_output_values=[0],
+            fallback_str="False",
         ),
         ComplexAggregatorExample(
             aggregator=SlopeAggregator(timestamp_col_name="timestamp"),
@@ -153,7 +155,7 @@ def test_aggregator(example: AggregatorExampleType):
             timestamp_col_name="timestamp",
         ),
         aggregators=[example.aggregator],
-        fallback=np.nan,
+        fallback=np.nan if example.aggregator.name != "bool" else False,
     )
 
     assert_frame_equal(result.collect(), example.expected_output)