CARGO-TEST(1) User Commands CARGO-TEST(1)

NAME

cargo-test -- Execute unit and integration tests of a package

SYNOPSIS

cargo test [options] [testname] [-- test-options]

DESCRIPTION

Compile and execute unit, integration, and documentation 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 and check out the rustc book's chapter on how tests
work at <https://doc.rust-lang.org/rustc/tests/index.html>.

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 a
special executable by linking your code with libtest. The executable
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.

If the package contains multiple test targets, each target compiles
to a special executable as aforementioned, and then is run serially.

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

Documentation tests are also run by default, which is handled by
rustdoc. It extracts code samples from documentation comments of the
library target, and then executes them.

Different from normal test targets, each code block compiles to a
doctest executable on the fly with rustc. These executables run in
parallel in separate processes. The compilation of a code block is in
fact a part of test function controlled by libtest, so some options
such as --jobs might not take effect. Note that this execution model
of doctests is not guaranteed and may change in the future; beware of
depending on it.

See the rustdoc book <https://doc.rust-lang.org/rustdoc/> for more
information on writing doc tests.

Working directory of tests

The working directory when running each unit and integration test is
set to the root directory of the package the test belongs to.
Setting the working directory of tests to the package's root
directory makes it possible for tests to reliably access the
package's files using relative paths, regardless from where cargo
test was executed from.

For documentation tests, the working directory when invoking rustdoc
is set to the workspace root directory, and is also the directory
rustdoc uses as the compilation directory of each documentation test.
The working directory when running each documentation test is set to
the root directory of the package the test belongs to, and is
controlled via rustdoc's --test-run-directory option.

OPTIONS

Test Options

--no-run
Compile, but don't run tests.

--no-fail-fast
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.

Package Selection

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.

-p spec<?>, --package spec<?>
Test only the specified packages. See cargo-pkgid(1) for the SPEC
format. This flag may be specified multiple times and supports
common Unix glob patterns like *, ? and []. However, to avoid
your shell accidentally expanding glob patterns before Cargo
handles them, you must use single quotes or double quotes around
each pattern.

--workspace
Test all members in the workspace.

--all
Deprecated alias for --workspace.

--exclude SPEC<?>
Exclude the specified packages. Must be used in conjunction with
the --workspace flag. This flag may be specified multiple times
and supports common Unix glob patterns like *, ? and []. However,
to avoid your shell accidentally expanding glob patterns before
Cargo handles them, you must use single quotes or double quotes
around each pattern.

Target Selection

When no target selection options are given, cargo test will build the
following targets of the selected packages:

+o lib -- used to link with binaries, examples, integration tests,
and doc tests

+o bins (only if integration tests are built and required features
are available)

+o examples -- to ensure they compile

+o lib as a unit test

+o bins as unit tests

+o integration tests

+o 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, replacing the example's main
function with the libtest harness. If you don't want the main
function replaced, also include harness = false, in which case the
example will be built and executed as-is.

Setting targets to test = false will stop them from being tested by
default. Target selection options that take a target by name (such
as --example foo) 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.

See Configuring a target
<https://doc.rust-lang.org/cargo/reference/cargo-targets.html#configuring-a-target>
for more information on per-target settings.

Binary targets are automatically built if there is an integration
test or benchmark being selected to test. This allows an integration
test to execute the binary to exercise and test its behavior. The
CARGO_BIN_EXE_<name> environment variable
<https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates>
is set when the integration test is built so that it can use the env
macro <https://doc.rust-lang.org/std/macro.env.html> to locate the
executable.

Passing target selection flags will test only the specified targets.

Note that --bin, --example, --test and --bench flags also support
common Unix glob patterns like *, ? and []. However, to avoid your
shell accidentally expanding glob patterns before Cargo handles them,
you must use single quotes or double quotes around each glob pattern.

--lib
Test the package's library.

--bin name<?>
Test the specified binary. This flag may be specified multiple
times and supports common Unix glob patterns.

--bins
Test all binary targets.

--example name<?>
Test the specified example. This flag may be specified multiple
times and supports common Unix glob patterns.

--examples
Test all example targets.

--test name<?>
Test the specified integration test. This flag may be specified
multiple times and supports common Unix glob patterns.

--tests
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.

--bench name<?>
Test the specified benchmark. This flag may be specified multiple
times and supports common Unix glob patterns.

--benches
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.

--all-targets
Test all targets. This is equivalent to specifying --lib --bins
--tests --benches --examples.

--doc
Test only the library's documentation. This cannot be mixed with
other target options.

Feature Selection

The feature flags allow you to control which features are enabled.
When no feature options are given, the default feature is activated
for every selected package.

See the features documentation
<https://doc.rust-lang.org/cargo/reference/features.html#command-line-feature-options>
for more details.

-F features, --features features
Space or comma separated list of features to activate. Features
of workspace members may be enabled with
package-name/feature-name syntax. This flag may be specified
multiple times, which enables all specified features.

--all-features
Activate all available features of all selected packages.

--no-default-features
Do not activate the default feature of the selected packages.

Compilation Options

--target triple
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 flag may be specified
multiple times.

This may also be specified with the build.target config value
<https://doc.rust-lang.org/cargo/reference/config.html>.

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
<https://doc.rust-lang.org/cargo/reference/build-cache.html>
documentation for more details.

-r, --release
Test optimized artifacts with the release profile. See also the
--profile option for choosing a specific profile by name.

--profile name
Test with the given profile. See the reference
<https://doc.rust-lang.org/cargo/reference/profiles.html> for
more details on profiles.

--timings=fmts
Output information how long each compilation takes, and track
concurrency information over time. Accepts an optional
comma-separated list of output formats; --timings without an
argument will default to --timings=html. Specifying an output
format (rather than the default) is unstable and requires
-Zunstable-options. Valid output formats:

+o html (unstable, requires -Zunstable-options): Write a
human-readable file cargo-timing.html to the
target/cargo-timings directory with a report of the
compilation. Also write a report to the same directory with a
timestamp in the filename if you want to look at older runs.
HTML output is suitable for human consumption only, and does
not provide machine-readable timing data.

+o json (unstable, requires -Zunstable-options): Emit
machine-readable JSON information about timing information.

Output Options

--target-dir directory
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
<https://doc.rust-lang.org/cargo/reference/config.html>.
Defaults to target in the root of the workspace.

Display Options

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

-v, --verbose
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
<https://doc.rust-lang.org/cargo/reference/config.html>.

-q, --quiet
Do not print cargo log messages. May also be specified with the
term.quiet config value
<https://doc.rust-lang.org/cargo/reference/config.html>.

--color when
Control when colored output is used. Valid values:

+o auto (default): Automatically detect if color support is
available on the terminal.

+o always: Always display colors.

+o never: Never display colors.

May also be specified with the term.color config value
<https://doc.rust-lang.org/cargo/reference/config.html>.

--message-format fmt
The output format for diagnostic messages. Can be specified
multiple times and consists of comma-separated values. Valid
values:

+o human (default): Display in a human-readable text format.
Conflicts with short and json.

+o short: Emit shorter, human-readable text messages. Conflicts
with human and json.

+o json: Emit JSON messages to stdout. See the reference
<https://doc.rust-lang.org/cargo/reference/external-tools.html#json-messages>
for more details. Conflicts with human and short.

+o json-diagnostic-short: Ensure the rendered field of JSON
messages contains the "short" rendering from rustc. Cannot be
used with human or short.

+o json-diagnostic-rendered-ansi: Ensure the rendered field of
JSON messages contains embedded ANSI color codes for
respecting rustc's default color scheme. Cannot be used with
human or short.

+o json-render-diagnostics: Instruct Cargo to not include rustc
diagnostics 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. Cannot be used with human or short.

Manifest Options

--manifest-path path
Path to the Cargo.toml file. By default, Cargo searches for the
Cargo.toml file in the current directory or any parent directory.

--ignore-rust-version
Ignore rust-version specification in packages.

--locked
Asserts that the exact same dependencies and versions are used as
when the existing Cargo.lock file was originally generated. Cargo
will exit with an error when either of the following scenarios
arises:

+o The lock file is missing.

+o Cargo attempted to change the lock file due to a different
dependency resolution.

It may be used in environments where deterministic builds are
desired, such as in CI pipelines.

--offline
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
<https://doc.rust-lang.org/cargo/reference/config.html>.

--frozen
Equivalent to specifying both --locked and --offline.

--lockfile-path PATH
Changes the path of the lockfile from the default
(<workspace_root>/Cargo.lock) to PATH. PATH must end with
Cargo.lock (e.g. --lockfile-path
/tmp/temporary-lockfile/Cargo.lock). Note that providing
--lockfile-path will ignore existing lockfile at the default
path, and instead will either use the lockfile from PATH, or
write a new lockfile into the provided PATH if it doesn't exist.
This flag can be used to run most commands in read-only
directories, writing lockfile into the provided PATH.

This option is only available on the nightly channel
<https://doc.rust-lang.org/book/appendix-07-nightly-rust.html>
and requires the -Z unstable-options flag to enable (see #14421
<https://github.com/rust-lang/cargo/issues/14421>).

Common Options

+toolchain
If Cargo has been installed with rustup, and the first argument
to cargo begins with +, it will be interpreted as a rustup
toolchain name (such as +stable or +nightly). See the rustup
documentation <https://rust-lang.github.io/rustup/overrides.html>
for more information about how toolchain overrides work.

--config KEY=VALUE or PATH
Overrides a Cargo configuration value. The argument should be in
TOML syntax of KEY=VALUE, or provided as a path to an extra
configuration file. This flag may be specified multiple times.
See the command-line overrides section
<https://doc.rust-lang.org/cargo/reference/config.html#command-line-overrides>
for more information.

-C PATH
Changes the current working directory before executing any
specified operations. This affects things like where cargo looks
by default for the project manifest (Cargo.toml), as well as the
directories searched for discovering .cargo/config.toml, for
example. This option must appear before the command name, for
example cargo -C path/to/my-project build.

This option is only available on the nightly channel
<https://doc.rust-lang.org/book/appendix-07-nightly-rust.html>
and requires the -Z unstable-options flag to enable (see #10098
<https://github.com/rust-lang/cargo/issues/10098>).

-h, --help
Prints help information.

-Z flag
Unstable (nightly-only) flags to Cargo. Run cargo -Z help for
details.

Miscellaneous Options

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

-j N, --jobs N
Number of parallel jobs to run. May also be specified with the
build.jobs config value
<https://doc.rust-lang.org/cargo/reference/config.html>. Defaults
to the number of logical CPUs. If negative, it sets the maximum
number of parallel jobs to the number of logical CPUs plus
provided value. If a string default is provided, it sets the
value back to defaults. Should not be 0.

--future-incompat-report
Displays a future-incompat report for any future-incompatible
warnings produced during execution of this command

See cargo-report(1)

While cargo test involves compilation, it does not provide a
--keep-going flag. Use --no-fail-fast to run as many tests as
possible without stopping at the first failure. To "compile" as many
tests as possible, use --tests to build test binaries separately. For
example:

cargo build --tests --keep-going
cargo test --tests --no-fail-fast

ENVIRONMENT

See the reference
<https://doc.rust-lang.org/cargo/reference/environment-variables.html>
for details on environment variables that Cargo reads.

EXIT STATUS

+o 0: Cargo succeeded.

+o 101: Cargo failed to complete.

EXAMPLES

1. Execute all the unit and integration tests of the current
package:

cargo test

2. Run only tests whose names match against a filter string:

cargo test name_filter

3. Run only a specific test within a specific integration test:

cargo test --test int_test_name -- modname::test_name

SEE ALSO

cargo(1), cargo-bench(1), types of tests
<https://doc.rust-lang.org/cargo/reference/cargo-targets.html#tests>,
how to write tests <https://doc.rust-lang.org/rustc/tests/index.html>

CARGO-TEST(1)