asserto 0.0.4a0

A fluent DSL for python assertions.

Asserto:

Asserto is a clean, fluent and powerful assertion library for python. We recommend using pytest as a test runner but asserto will work well with any test runner.

Asserto was developed using pytest as it's test runner and has a pytest-asserto plugin that exposes asserto through a fixture. Asserto will work on any runner or even without one. Note: It is common practice for a test runner to apply assertion rewriting to change the behaviour of the assert keyword under the hood.

The main features of asserto are (and will be):

• Chainable and Fluent API.
• Ability for both Hard and Soft assertions.
• Rich diffs to highlight problems, reduce churn and improve effeciency and debuggability.
• Dynamic assertions; check any obj attribute or invoke any of it's function types.
• Robust set of methods out of the box for common types.
• Extensibility. Bolt on your own assetions at runtime.
• Human error detection, elaborate warnings when something is amiss.
• Much more to come.

Usage:

from asserto import asserto

def test_foo() -> None:
    asserto("Hello").has_length(5).matches(r"\w{5}$").ends_with("lo").starts_with("Hel")

If you use pytest; a fixture is available for an Asserto factory function:

def test_bar(asserto) -> None:  # No imports; just use the fixture.
    asserto("Hello").has_length(5).matches(r"\w{4}$").ends_with("lo").starts_with("Hel")

If you want to check many assertions in a single test without failing until after all:

def test_baz(asserto) -> None:
    with asserto("Baz") as context:
        # asserto when used in a python context is run in 'soft' mode;
        # upon exiting the context; congregated errors are subsequently raised (if any)
        context.starts_with("B")
        context.ends_with("z")
        context.is_equal_to("Baz")
        context.is_length(2)  # Uh oh a failure!

Results in:

    def test_foo(asserto) -> None:
>       with asserto("Bar") as context:
E       AssertionError: 1 Soft Assertion Failures
E       [AssertionError("Length of: 'Bar' was not equal to: 2")]