Built-in strategies¶

This page shows some of the strategies that Hypothesis provides for you.

Strategies provided by Hypothesis¶

Here is a selection of strategies provided by Hypothesis that may be useful to know:

integers(): Generates integers.
floats(): Generates floats.
booleans(): Generates booleans.
text(): Generates unicode strings (i.e., instances of python:str). Can be constrained to ASCII with st.text(st.characters(codec="ascii")).
lists(): Generates lists with elements from the strategy passed to it. st.lists(st.integers()) generates lists of integers.
tuples(): Generates tuples of a fixed length. st.tuples(st.integers(), st.floats()) generates tuples with two elements, where the first element is an integer and the second is a float.
one_of(): Generates from any of the strategies passed to it. st.one_of(st.integers(), st.floats()) generates either integers or floats. You can also use | to construct one_of(), like st.integers() | st.floats().
builds(): Generates instances of a class (or other callable) by specifying a strategy for each argument, like st.builds(Person, name=st.text(), age=st.integers()).
just(): Generates the exact value passed to it. st.just("a") generates the exact string "a". This is useful when something expects to be passed a strategy. For instance, st.lists(st.integers() | st.just("a")) generates lists whose elements are either integers or the string "a".
sampled_from(): Generates a random value from a list. st.sampled_from(["a", 1]) is roughly equivalent to st.just("a") | st.just(1).
none(): Generates None. Useful for parameters that can be optional, like st.integers() | st.none().