Struct Assertion

pub struct Assertion { /* private fields */ }

A specific set of criteria to enforce on matching spans.

Assertions represent both a span “matcher” – which controls which spans the criteria are applied to – and the criteria themselves, which define the behavior to assert against the matching spans.

Matching behavior

As an Assertion can match multiple spans, care must be taken when building the Assertion to constrain the matcher correctly. For example, if you want to focus on a specific span, you would want to use match on the span name at a minimum, and potentially match on the span target if there were other spans with the same name in different modules. However, if you simply wanted to check if any spans under a specific module path were created – perhaps to assert that a particular codeflow is being exercised, but not assert how it’s being exercised – then only specifying the span target might suffice.

Implementations

impl Assertion

pub fn assert(&self)

Asserts that all criteria have been met.

Uses the “assert” macros from the standard library, so criterion which have not been met will cause a panic, similar to using the “assert” macros directly.

For a fallible assertion that can be called over and over without panicking, [try_assert] can be used instead.

pub fn try_assert(&self) -> bool

Attempts to assert that all criteria have been met.

If any of the criteria have not yet been met, false will be returned. Otherwise, true will be returned.

If assertions should end your test immediately, assert can be used instead.

Trait Implementations

impl Drop for Assertion

fn drop(&mut self)

Executes the destructor for this type.