Provided by: cargo_0.47.0-1~exp1ubuntu1~16.04.1_amd64 
NAME
cargo-test - Execute unit and integration tests of a package
SYNOPSIS
cargo test [OPTIONS] [TESTNAME] [-- TEST-OPTIONS]
DESCRIPTION
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 <https://doc.rust-lang.org/rustdoc/> for
more information on writing doc tests.
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.
--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.
Target Selection
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.
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 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.
--lib
Test the package’s library.
--bin NAME...
Test the specified binary. This flag may be specified multiple times.
--bins
Test all binary targets.
--example NAME...
Test the specified example. This flag may be specified multiple times.
--examples
Test all example targets.
--test NAME...
Test the specified integration test. This flag may be specified multiple times.
--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.
--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 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.
--features FEATURES
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.
--all-features
Activate all available features of all selected packages.
--no-default-features
Do not activate the default feature of the current directory’s package.
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 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/guide/build-cache.html> documentation for more details.
--release
Test optimized artifacts with the release profile. See the PROFILES section for details on how this
affects profile selection.
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
No output printed to stdout.
--color WHEN
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
<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:
• 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
<https://doc.rust-lang.org/cargo/reference/external-tools.html#json-messages> 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.
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.
--frozen, --locked
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.
--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>.
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://github.com/rust-lang/rustup/> for more information about how toolchain overrides work.
-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 CPUs.
PROFILES
Profiles may be used to configure compiler options such as optimization levels and debug settings. See
the reference <https://doc.rust-lang.org/cargo/reference/profiles.html> 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 │ dev │ release │
├────────────────────────────┼─────────────────┼───────────────────┤
│ │ │ │
│ test, bench, or any target │ test │ bench │
│ in "test" or "bench" mode │ │ │
└────────────────────────────┴─────────────────┴───────────────────┘
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.
ENVIRONMENT
See the reference <https://doc.rust-lang.org/cargo/reference/environment-variables.html> for details on
environment variables that Cargo reads.
EXIT STATUS
0
Cargo succeeded.
101
Cargo failed to complete.
EXAMPLES
1. Execute all the unit and integration tests of the current package:
cargo test
2. 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)
2020-06-25 CARGO-TEST(1)