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 and run so that it can use the
env macro <https://doc.rust-lang.org/std/macro.env.html> or the var
function <https://doc.rust-lang.org/std/env/fn.var.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 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 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 specified target architecture. Flag may be specified
multiple times. The default is the host architecture. The general
format of the triple is <arch><sub>-<vendor>-<sys>-<abi>.
Possible values:
o Any supported target in rustc --print target-list.
o "host-tuple", which will internally be substituted by the
host’s target. This can be particularly useful if you’re
cross-compiling some crates, and don’t want to specify your
host’s machine as a target (for instance, an xtask in a shared
project that may be worked on by many hosts).
o A path to a custom target specification. See Custom Target Lookup
Path
<https://doc.rust-lang.org/rustc/targets/custom.html#custom-target-lookup-path>
for more information.
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
Output information how long each compilation takes, and track
concurrency information over time.
A file cargo-timing.html will be written to the target/cargo-timings
directory at the end of the build. An additional report with a
timestamp in its filename is also written if you want to look at a
previous run. These reports are suitable for human consumption only,
and do not provide machine-readable timing data.
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 --no-capture to the test binaries:
cargo test -- --no-capture
-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.
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>