cargo test foo -- --test-threads 3
cargo-test - Execute unit and integration tests of a package
cargo test [OPTIONS] [TESTNAME] [-- TEST-OPTIONS]
Compile and execute unit and integration tests.
The test filtering argument TESTNAME
and all the arguments following the two
dashes (--
) are passed to the test binaries and thus to libtest (rustc’s
built in unit-test and micro-benchmarking framework). If you’re passing
arguments to both Cargo and the binary, the ones after --
go to the binary,
the ones before go to Cargo. For details about libtest’s arguments see the
output of cargo test -- --help
. As an example, this will run all tests with
foo
in their name on 3 threads in parallel:
cargo test foo -- --test-threads 3
Tests are built with the --test
option to rustc
which creates an
executable with a main
function that automatically runs all functions
annotated with the #[test]
attribute in multiple threads. #[bench]
annotated functions will also be run with one iteration to verify that they
are functional.
The libtest harness may be disabled by setting harness = false
in the target
manifest settings, in which case your code will need to provide its own main
function to handle running tests.
Documentation tests are also run by default, which is handled by rustdoc
. It
extracts code samples from documentation comments and executes them. See the
rustdoc book for more information on
writing doc tests.
Compile, but don’t run tests.
Run all tests regardless of failure. Without this flag, Cargo will exit after the first executable fails. The Rust test harness will run all tests within the executable to completion, this flag only applies to the executable as a whole.
By default, when no package selection options are given, the packages selected
depend on the selected manifest file (based on the current working directory if
--manifest-path
is not given). If the manifest is the root of a workspace then
the workspaces default members are selected, otherwise only the package defined
by the manifest will be selected.
The default members of a workspace can be set explicitly with the
workspace.default-members
key in the root manifest. If this is not set, a
virtual workspace will include all workspace members (equivalent to passing
--workspace
), and a non-virtual workspace will include only the root crate itself.
Test only the specified packages. See cargo-pkgid(1) for the SPEC format. This flag may be specified multiple times.
Test all members in the workspace.
Deprecated alias for --workspace
.
Exclude the specified packages. Must be used in conjunction with the
--workspace
flag. This flag may be specified multiple times.
When no target selection options are given, cargo test
will build the
following targets of the selected packages:
lib — used to link with binaries, examples, integration tests, and doc tests
bins (only if integration tests are built and required features are available)
examples — to ensure they compile
lib as a unit test
bins as unit tests
integration tests
doc tests for the lib target
The default behavior can be changed by setting the test
flag for the target
in the manifest settings. Setting examples to test = true
will build and run
the example as a test. Setting targets to test = false
will stop them from
being tested by default. Target selection options that take a target by name
ignore the test
flag and will always test the given target.
Doc tests for libraries may be disabled by setting doctest = false
for the
library in the manifest.
Passing target selection flags will test only the specified targets.
Test the package’s library.
Test the specified binary. This flag may be specified multiple times.
Test all binary targets.
Test the specified example. This flag may be specified multiple times.
Test all example targets.
Test the specified integration test. This flag may be specified multiple times.
Test all targets in test mode that have the test = true
manifest
flag set. By default this includes the library and binaries built as
unittests, and integration tests. Be aware that this will also build any
required dependencies, so the lib target may be built twice (once as a
unittest, and once as a dependency for binaries, integration tests, etc.).
Targets may be enabled or disabled by setting the test
flag in the
manifest settings for the target.
Test the specified benchmark. This flag may be specified multiple times.
Test all targets in benchmark mode that have the bench = true
manifest flag set. By default this includes the library and binaries built
as benchmarks, and bench targets. Be aware that this will also build any
required dependencies, so the lib target may be built twice (once as a
benchmark, and once as a dependency for binaries, benchmarks, etc.).
Targets may be enabled or disabled by setting the bench
flag in the
manifest settings for the target.
Test all targets. This is equivalent to specifying --lib --bins
--tests --benches --examples
.
Test only the library’s documentation. This cannot be mixed with other target options.
When no feature options are given, the default
feature is activated for
every selected package.
Space or comma separated list of features to activate. These features only
apply to the current directory’s package. Features of direct dependencies
may be enabled with <dep-name>/<feature-name>
syntax. This flag may be
specified multiple times, which enables all specified features.
Activate all available features of all selected packages.
Do not activate the default
feature of the current directory’s
package.
Test for the given architecture. The default is the host
architecture. The general format of the triple is
<arch><sub>-<vendor>-<sys>-<abi>
. Run rustc --print target-list
for a
list of supported targets.
This may also be specified with the build.target
config value.
Note that specifying this flag makes Cargo run in a different mode where the target artifacts are placed in a separate directory. See the build cache documentation for more details.
Test optimized artifacts with the release
profile. See the
PROFILES section for details on how this affects profile selection.
Directory for all generated artifacts and intermediate files. May also be
specified with the CARGO_TARGET_DIR
environment variable, or the
build.target-dir
config value. Defaults
to target
in the root of the workspace.
By default the Rust test harness hides output from test execution to keep
results readable. Test output can be recovered (e.g., for debugging) by passing
--nocapture
to the test binaries:
cargo test -- --nocapture
Use verbose output. May be specified twice for "very verbose" output which
includes extra output such as dependency warnings and build script output.
May also be specified with the term.verbose
config value.
No output printed to stdout.
Control when colored output is used. Valid values:
auto
(default): Automatically detect if color support is available on the
terminal.
always
: Always display colors.
never
: Never display colors.
May also be specified with the term.color
config value.
The output format for diagnostic messages. Can be specified multiple times and consists of comma-separated values. Valid values:
human
(default): Display in a human-readable text format.
short
: Emit shorter, human-readable text messages.
json
: Emit JSON messages to stdout. See
the reference
for more details.
json-diagnostic-short
: Ensure the rendered
field of JSON messages contains
the "short" rendering from rustc.
json-diagnostic-rendered-ansi
: Ensure the rendered
field of JSON messages
contains embedded ANSI color codes for respecting rustc’s default color
scheme.
json-render-diagnostics
: Instruct Cargo to not include rustc diagnostics in
in JSON messages printed, but instead Cargo itself should render the
JSON diagnostics coming from rustc. Cargo’s own JSON diagnostics and others
coming from rustc are still emitted.
Path to the Cargo.toml
file. By default, Cargo searches for the
Cargo.toml
file in the current directory or any parent directory.
Either of these flags requires that the Cargo.lock
file is
up-to-date. If the lock file is missing, or it needs to be updated, Cargo will
exit with an error. The --frozen
flag also prevents Cargo from
attempting to access the network to determine if it is out-of-date.
These may be used in environments where you want to assert that the
Cargo.lock
file is up-to-date (such as a CI build) or want to avoid network
access.
Prevents Cargo from accessing the network for any reason. Without this flag, Cargo will stop with an error if it needs to access the network and the network is not available. With this flag, Cargo will attempt to proceed without the network if possible.
Beware that this may result in different dependency resolution than online mode. Cargo will restrict itself to crates that are downloaded locally, even if there might be a newer version as indicated in the local copy of the index. See the cargo-fetch(1) command to download dependencies before going offline.
May also be specified with the net.offline
config value.
Prints help information.
Unstable (nightly-only) flags to Cargo. Run cargo -Z help
for
details.
The --jobs
argument affects the building of the test executable but does not
affect how many threads are used when running the tests. The Rust test harness
includes an option to control the number of threads used:
cargo test -j 2 -- --test-threads=2
Number of parallel jobs to run. May also be specified with the
build.jobs
config value. Defaults to
the number of CPUs.
Profiles may be used to configure compiler options such as optimization levels and debug settings. See the reference for more details.
Profile selection depends on the target and crate being built. By default the
dev
or test
profiles are used. If the --release
flag is given, then the
release
or bench
profiles are used.
Target | Default Profile | --release Profile |
---|---|---|
lib, bin, example |
|
|
test, bench, or any target |
|
|
Dependencies use the dev
/release
profiles.
Unit tests are separate executable artifacts which use the test
/bench
profiles. Example targets are built the same as with cargo build
(using the
dev
/release
profiles) unless you are building them with the test harness
(by setting test = true
in the manifest or using the --example
flag) in
which case they use the test
/bench
profiles. Library targets are built
with the dev
/release
profiles when linked to an integration test, binary,
or doctest.
See the reference for details on environment variables that Cargo reads.
Cargo succeeded.
Cargo failed to complete.
Execute all the unit and integration tests of the current package:
cargo test
Run only a specific test within a specific integration test:
cargo test --test int_test_name -- modname::test_name