Post Initialization Hooks

spock supports post initialization (post-init) hooks via the __post_hook__ method within a @spock decorated class. These methods are automatically called after the Spockspace object is created thus allow the user to do any post instantiation work (such as validation).

Creating and Using Post-Init Hooks

Simply add the __post_hook__ method to your @spock decorated class:

from spock import spockfrom spock.utils import within, gefrom typing import List

def my_post_init_hook(list_vals: List[float], sum_val: float):    if sum(list_vals) != sum_val:        raise ValueError(f"Sum of `{sum(list_vals)}` does not equal 1.0")

@spockclass PostInitExample:    list_vals: List[float] = [0.5, 0.25, 0.25]    check_sum: float = 1.0    my_value: float = 1.2    other: float = 0.1    lower_bound: float = 0.0        def __post_hook__(self):        # Validate that value is between 0.0 and 1.0 (inclusive)        within(self.my_value, low_bound=0.0, upper_bound=1.0, inclusive_lower=True, inclusive_upper=True)        # Validate that other is greater than lower_bound        ge(self.other, bound=self.lower_bound)        my_post_init_hook(self.list_vals, self.check_sum)

The __post_hook__ method will be triggered post instantiation. Therefore, the example above will throw an Exception since the value of my_value does not fall within the given bounds. Also notice that you can reference other defined parameters within the __post_hook__ methods and use them in custom functions (here we use lower_bound and check_sum to do some validation comparisons)

Common Post Initialization Hooks

spock provides some common validators (in the utils module) that would be typically run as post-init hooks including: greater than (gt), greater than or equals to (ge), less than (lt), less than or equals to (le), and if a parameter falls within a set of inclusive/exclusive bounds (within).