Struct tracing_subscriber::fmt::TestWriter
source · [−]pub struct TestWriter { /* private fields */ }
Expand description
A writer intended to support libtest
’s output capturing for use in unit tests.
TestWriter
is used by fmt::Subscriber
or fmt::Layer
to enable capturing support.
cargo test
can only capture output from the standard library’s print!
macro. See
libtest
’s output capturing for more details about output capturing.
Writing to io::stdout
and io::stderr
produces the same results as using
libtest
’s --nocapture
option which may make the results look unreadable.
Implementations
sourceimpl TestWriter
impl TestWriter
Trait Implementations
sourceimpl Debug for TestWriter
impl Debug for TestWriter
sourceimpl Default for TestWriter
impl Default for TestWriter
sourcefn default() -> TestWriterⓘNotable traits for TestWriterimpl Write for TestWriter
fn default() -> TestWriterⓘNotable traits for TestWriterimpl Write for TestWriter
Returns the “default value” for a type. Read more
sourceimpl<'a> MakeWriter<'a> for TestWriter
impl<'a> MakeWriter<'a> for TestWriter
type Writer = Self
type Writer = Self
The concrete io::Write
implementation returned by make_writer
. Read more
sourcefn make_writer(&'a self) -> Self::Writer
fn make_writer(&'a self) -> Self::Writer
sourceimpl Write for TestWriter
impl Write for TestWriter
sourcefn write(&mut self, buf: &[u8]) -> Result<usize>
fn write(&mut self, buf: &[u8]) -> Result<usize>
Write a buffer into this writer, returning how many bytes were written. Read more
sourcefn flush(&mut self) -> Result<()>
fn flush(&mut self) -> Result<()>
Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
sourcefn is_write_vectored(&self) -> bool
fn is_write_vectored(&self) -> bool
Determines if this Write
r has an efficient write_vectored
implementation. Read more
1.0.0 · sourcefn write_all(&mut self, buf: &[u8]) -> Result<(), Error>
fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>
Attempts to write an entire buffer into this writer. Read more
sourcefn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>
fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>
Attempts to write multiple buffers into this writer. Read more
Auto Trait Implementations
impl RefUnwindSafe for TestWriter
impl Send for TestWriter
impl Sync for TestWriter
impl Unpin for TestWriter
impl UnwindSafe for TestWriter
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<'a, M> MakeWriterExt<'a> for M where
M: MakeWriter<'a>,
impl<'a, M> MakeWriterExt<'a> for M where
M: MakeWriter<'a>,
sourcefn with_max_level(self, level: Level) -> WithMaxLevel<Self> where
Self: Sized,
fn with_max_level(self, level: Level) -> WithMaxLevel<Self> where
Self: Sized,
Wraps self
and returns a MakeWriter
that will only write output
for events at or below the provided verbosity Level
. For instance,
Level::TRACE
is considered to be _more verbosethan
Level::INFO`. Read more
sourcefn with_min_level(self, level: Level) -> WithMinLevel<Self> where
Self: Sized,
fn with_min_level(self, level: Level) -> WithMinLevel<Self> where
Self: Sized,
Wraps self
and returns a MakeWriter
that will only write output
for events at or above the provided verbosity Level
. Read more
sourcefn with_filter<F>(self, filter: F) -> WithFilter<Self, F> where
Self: Sized,
F: Fn(&Metadata<'_>) -> bool,
fn with_filter<F>(self, filter: F) -> WithFilter<Self, F> where
Self: Sized,
F: Fn(&Metadata<'_>) -> bool,
Wraps self
with a predicate that takes a span or event’s Metadata
and returns a bool
. The returned MakeWriter
’s
MakeWriter::make_writer_for
method will check the predicate to
determine if a writer should be produced for a given span or event. Read more
sourcefn and<B>(self, other: B) -> Tee<Self, B>ⓘNotable traits for Tee<A, B>impl<A, B> Write for Tee<A, B> where
A: Write,
B: Write,
where
Self: Sized,
B: MakeWriter<'a> + Sized,
fn and<B>(self, other: B) -> Tee<Self, B>ⓘNotable traits for Tee<A, B>impl<A, B> Write for Tee<A, B> where
A: Write,
B: Write,
where
Self: Sized,
B: MakeWriter<'a> + Sized,
A: Write,
B: Write,
Combines self
with another type implementing MakeWriter
, returning
a new MakeWriter
that produces writers that write to both
outputs. Read more
sourcefn or_else<W, B>(self, other: B) -> OrElse<Self, B> where
Self: MakeWriter<'a, Writer = OptionalWriter<W>> + Sized,
B: MakeWriter<'a> + Sized,
W: Write,
fn or_else<W, B>(self, other: B) -> OrElse<Self, B> where
Self: MakeWriter<'a, Writer = OptionalWriter<W>> + Sized,
B: MakeWriter<'a> + Sized,
W: Write,
Combines self
with another type implementing MakeWriter
, returning
a new MakeWriter
that calls other
’s make_writer
if self
’s
make_writer
returns OptionalWriter::none
. Read more