🛈 Note: This is pre-release documentation for the upcoming tracing 0.2.0 ecosystem.

For the release documentation, please see docs.rs, instead.

tracing_mock::field

Struct ExpectedField

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pub struct ExpectedField { /* private fields */ }
Expand description

An expected field.

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

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impl ExpectedField

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

Adds an additional ExpectedField to be matched.

Both fields must match, if either of them are not present, or if the value for either field is different, 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();
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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

The following test passes despite the recorded event having fields that were not expected because only was not used:

use tracing_mock::{collector, expect};

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

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 we include only on the ExpectedField then the test will fail:

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§

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impl Debug for ExpectedField

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

Formats the value using the given formatter. Read more
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impl From<ExpectedField> for ExpectedFields

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fn from(field: ExpectedField) -> Self

Converts to this type from the input type.

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WithCollector for T

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fn with_collector<C>(self, collector: C) -> WithDispatch<Self>
where C: Into<Dispatch>,

Attaches the provided collector to this type, returning a WithDispatch wrapper. Read more
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fn with_current_collector(self) -> WithDispatch<Self>

Attaches the current default collector to this type, returning a WithDispatch wrapper. Read more