cargo-test - Execute unit and integration tests of a package
cargo test [options] [testname] [
Compile and execute unit and integration tests.
The test filtering argument
TESTNAME and all the arguments following the two
--) 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
cargo test -- --help.
As an example, this will filter for tests with
foo in their name and run them
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.
annotated functions will also be run with one iteration to verify that they
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
function to handle running tests.
Documentation tests are also run by default, which is handled by
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
- Exclude the specified packages. Must be used in conjunction with the
--workspaceflag. 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
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.
Binary targets are automatically built if there is an integration test or
benchmark. This allows an integration test to execute the binary to exercise
and test its behavior. The
is set when the integration test is built so that it can use the
env macro to locate the
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 = truemanifest 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
testflag 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 = truemanifest 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
benchflag in the manifest settings for the target.
- Test all targets. This is equivalent to specifying
--lib --bins --tests --benches --examples.
The feature flags allow you to control the enabled features for the "current"
package. The "current" package is the package in the current directory, or the
one specified in
--manifest-path. If running in the root of a virtual
workspace, then the default features are selected for all workspace members,
or all features if
--all-features is specified.
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
defaultfeature of the current directory's package.
- Test for the given architecture. The default is the host
architecture. The general format of the triple is
rustc --print target-listfor a list of supported targets.
This may also be specified with the
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
releaseprofile. 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_DIRenvironment variable, or the
build.target-dirconfig value. Defaults to
targetin 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
- 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
- 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
renderedfield of JSON messages contains the "short" rendering from rustc.
json-diagnostic-rendered-ansi: Ensure the
renderedfield 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.tomlfile. By default, Cargo searches for the
Cargo.tomlfile in the current directory or any parent directory.
- Either of these flags requires that the
Cargo.lockfile is up-to-date. If the lock file is missing, or it needs to be updated, Cargo will exit with an error. The
--frozenflag 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.lockfile 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
- If Cargo has been installed with rustup, and the first argument to
+, it will be interpreted as a rustup toolchain name (such as
+nightly). See the rustup documentation for more information about how toolchain overrides work.
- Prints help information.
- Unstable (nightly-only) flags to Cargo. Run
cargo -Z helpfor details.
--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.jobsconfig 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
test profiles are used. If the
--release flag is given, then the
bench profiles are used.
|lib, bin, example|
|test, bench, or any target in "test" or "bench" mode|
Dependencies use the
Unit tests are separate executable artifacts which use the
profiles. Example targets are built the same as with
cargo build (using the
release profiles) unless you are building them with the test harness
test = true in the manifest or using the
--example flag) in
which case they use the
bench profiles. Library targets are built
release profiles when linked to an integration test, binary,
See the reference for details on environment variables that Cargo reads.
0: Cargo succeeded.
101: Cargo failed to complete.
Execute all the unit and integration tests of the current package:
Run only tests whose names match against a filter string:
cargo test name_filter
Run only a specific test within a specific integration test:
cargo test --test int_test_name -- modname::test_name