Custom Tests
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-Tests work like filters just that there is no way for a filter to get access
+Tests work like filters just that there is no way for a test to get access
to the environment or context and that they can't be chained. The return
-value of a filter should be `True` or `False`. The purpose of a filter is to
+value of a test should be `True` or `False`. The purpose of a test is to
give the template designers the possibility to perform type and conformability
checks.
-Here a simple filter that checks if a variable is a prime number::
+Here a simple test that checks if a variable is a prime number::
import math