Struct tracing_mock::field::ExpectedField

pub struct ExpectedField { /* private fields */ }

An expected field.

For a detailed description and examples, see the documentation for the methods and the field module.

Implementations

impl ExpectedField

pub fn with_value(self, value: &dyn Value) -> Self

Sets the value to expect when matching this field.

If the recorded value for this field diffs, the expectation will fail.

Examples

use tracing_mock::{collector, expect};

let event = expect::event()
    .with_fields(expect::field("field_name").with_value(&"value"));

let (collector, handle) = collector::mock()
    .event(event)
    .run_with_handle();

tracing::collect::with_default(collector, || {
    tracing::info!(field_name = "value");
});

handle.assert_finished();

A different value will cause the test to fail:

use tracing_mock::{collector, expect};

let event = expect::event()
    .with_fields(expect::field("field_name").with_value(&"value"));

let (collector, handle) = collector::mock()
    .event(event)
    .run_with_handle();

tracing::collect::with_default(collector, || {
    tracing::info!(field_name = "different value");
});

handle.assert_finished();

pub fn and(self, other: ExpectedField) -> ExpectedFields

Adds an additional ExpectedField to be matched.

Any fields introduced by .and must also match. If any fields are not present, or if the value for any field is different, then the expectation will fail.

Examples

use tracing_mock::{collector, expect};

let event = expect::event().with_fields(
    expect::field("field")
        .with_value(&"value")
        .and(expect::field("another_field").with_value(&42)),
);

let (collector, handle) = collector::mock()
    .event(event)
    .run_with_handle();

tracing::collect::with_default(collector, || {
    tracing::info!(
        field = "value",
        another_field = 42,
    );
});

handle.assert_finished();

If the second field is not present, the test will fail:

use tracing_mock::{collector, expect};

let event = expect::event().with_fields(
    expect::field("field")
        .with_value(&"value")
        .and(expect::field("another_field").with_value(&42)),
);

let (collector, handle) = collector::mock()
    .event(event)
    .run_with_handle();

tracing::collect::with_default(collector, || {
    tracing::info!(field = "value");
});

handle.assert_finished();

pub fn only(self) -> ExpectedFields

Indicates that no fields other than those specified should be expected.

If additional fields are present on the recorded event or span, the expectation will fail.

Examples

Check that only a single field is recorded.

use tracing_mock::{collector, expect};

let event = expect::event()
    .with_fields(expect::field("field").with_value(&"value").only());

let (collector, handle) = collector::mock().event(event).run_with_handle();

tracing::collect::with_default(collector, || {
    tracing::info!(field = "value");
});

handle.assert_finished();

The following example fails because a second field is recorded.

use tracing_mock::{collector, expect};

let event = expect::event()
    .with_fields(expect::field("field").with_value(&"value").only());

let (collector, handle) = collector::mock().event(event).run_with_handle();

tracing::collect::with_default(collector, || {
    tracing::info!(field = "value", another_field = 42,);
});

handle.assert_finished();

Trait Implementations

impl Debug for ExpectedField

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<ExpectedField> for ExpectedFields

fn from(field: ExpectedField) -> Self

Converts to this type from the input type.