diff --git a/tests/pipeline/test_filter.py b/tests/pipeline/test_filter.py
index 461f5beb..a3e090f6 100644
--- a/tests/pipeline/test_filter.py
+++ b/tests/pipeline/test_filter.py
@@ -410,7 +410,7 @@ class FilterTestCase(BasePipelineTestCase):
 
         strictly_true_filter = StrictlyTrueFilter(
             inputs=(InputFilter(), ),
-            window_length=self.default_shape[0]
+            window_length=(self.default_shape[0]-1)
         )
 
         results = self.run_graph(
@@ -418,11 +418,18 @@ class FilterTestCase(BasePipelineTestCase):
             initial_workspace={InputFilter(): data}
         )
 
-        expected_result = full(self.default_shape[1], False, dtype=bool)
-        expected_result[0] = True
+        expected_result_0 = full(self.default_shape[1], False, dtype=bool)
+        expected_result_0[0] = True
         check_arrays(
-            reshape(results['Filter'], expected_result.shape[0]),
-            expected_result,
+            reshape(results['Filter'][0], expected_result_0.shape[0]),
+            expected_result_0,
+        )
+
+        expected_result_1 = full(self.default_shape[1], False, dtype=bool)
+        expected_result_1[:2] = True
+        check_arrays(
+            reshape(results['Filter'][1], expected_result_1.shape[0]),
+            expected_result_1,
         )
 
     @parameter_space(factor_len=[2, 3, 4])