ctest - Man Page

• Run all tests defined in the CMake project, executing 4 jobs at a time in parallel: ctest -j4 --output-on-failure
• List available tests: ctest -N
• Run a single test based on its name, or filter on a regular expression: ctest --output-on-failure -R '^test_name$'

tldr.sh

ctest — CTest Command-Line Reference

Run Tests
 ctest [<options>] [--test-dir <path-to-build>]

Build and Test Mode
 ctest --build-and-test <path-to-source> <path-to-build>
       --build-generator <generator> [<options>...]
      [--build-options <opts>...]
      [--test-command <command> [<args>...]]

Dashboard Client
 ctest -D <dashboard>         [-- <dashboard-options>...]
 ctest -M <model> -T <action> [-- <dashboard-options>...]
 ctest -S <script>            [-- <dashboard-options>...]
 ctest -SP <script>           [-- <dashboard-options>...]

View Help
 ctest --help[-<topic>]

The ctest executable is the CMake test driver program. CMake-generated build trees created for projects that use the enable_testing() and add_test() commands have testing support. This program will run the tests and report results.

--preset <preset>, --preset=<preset>

Use a test preset to specify test options. The project binary directory is inferred from the configurePreset key. The current working directory must contain CMake preset files. See preset for more details.

--list-presets

Lists the available test presets. The current working directory must contain CMake preset files.

-C <cfg>, --build-config <cfg>

Choose configuration to test.

Some CMake-generated build trees can have multiple build configurations in the same tree.  This option can be used to specify which one should be tested.  Example configurations are Debug and Release.

--progress

Enable short progress output from tests.

When the output of ctest is being sent directly to a terminal, the progress through the set of tests is reported by updating the same line rather than printing start and end messages for each test on new lines. This can significantly reduce the verbosity of the test output. Test completion messages are still output on their own line for failed tests and the final test summary will also still be logged.

This option can also be enabled by setting the environment variable CTEST_PROGRESS_OUTPUT.

-V,  --verbose

Enable verbose output from tests.

Test output is normally suppressed and only summary information is displayed.  This option will show all test output.

-VV,  --extra-verbose

Enable more verbose output from tests.

Test output is normally suppressed and only summary information is displayed.  This option will show even more test output.

--debug

Displaying more verbose internals of CTest.

This feature will result in a large number of output that is mostly useful for debugging dashboard problems.

--output-on-failure

Output anything outputted by the test program if the test should fail. This option can also be enabled by setting the CTEST_OUTPUT_ON_FAILURE environment variable

--stop-on-failure

Stop running the tests when the first failure happens.

-F

Enable failover.

This option allows CTest to resume a test set execution that was previously interrupted.  If no interruption occurred, the -F option will have no effect.

-j [<level>], --parallel [<level>]

Run tests in parallel, optionally limited to a given level of parallelism.

Added in version 3.29: The <level> may be omitted, or 0, in which case:

• Under Job Server Integration, parallelism is limited by available job tokens.
• Otherwise, if the value is omitted, parallelism is limited by the number of processors, or 2, whichever is larger.
• Otherwise, if the value is 0, parallelism is unbounded.

This option may instead be specified by the CTEST_PARALLEL_LEVEL environment variable.

This option can be used with the PROCESSORS test property. See the Label and Subproject Summary.

--resource-spec-file <file>

Run CTest with resource allocation enabled, using the resource specification file specified in <file>.

When ctest is run as a Dashboard Client this sets the ResourceSpecFile option of the CTest Test Step.

--test-load <level>

While running tests in parallel (e.g. with -j), try not to start tests when they may cause the CPU load to pass above a given threshold.

When ctest is run as a Dashboard Client this sets the TestLoad option of the CTest Test Step.

-Q,  --quiet

Make CTest quiet.

This option will suppress all the output.  The output log file will still be generated if the --output-log is specified.  Options such as --verbose, --extra-verbose, and --debug are ignored if --quiet is specified.

-O <file>, --output-log <file>

Output to log file.

This option tells CTest to write all its output to a <file> log file.

--output-junit <file>

Added in version 3.21.

Write test results in JUnit format.

This option tells CTest to write test results to <file> in JUnit XML format. If <file> already exists, it will be overwritten. If using the -S option to run a dashboard script, use the OUTPUT_JUNIT keyword with the ctest_test() command instead.

-N,  --show-only[=<format>]

Disable actual execution of tests.

This option tells CTest to list the tests that would be run but not actually run them.  Useful in conjunction with the -R and -E options.

Added in version 3.14: The --show-only option accepts a <format> value.

<format> can be one of the following values.

human

Human-friendly output.  This is not guaranteed to be stable. This is the default.

json-v1

Dump the test information in JSON format. See Show as JSON Object Model.

-L <regex>, --label-regex <regex>

Run tests with labels matching regular expression as described under string(REGEX).

This option tells CTest to run only the tests whose labels match the given regular expression.  When more than one -L option is given, a test will only be run if each regular expression matches at least one of the test's labels (i.e. the multiple -L labels form an AND relationship).  See Label Matching.

-R <regex>, --tests-regex <regex>

Run tests matching regular expression.

This option tells CTest to run only the tests whose names match the given regular expression.

-E <regex>, --exclude-regex <regex>

Exclude tests matching regular expression.

This option tells CTest to NOT run the tests whose names match the given regular expression.

-LE <regex>, --label-exclude <regex>

Exclude tests with labels matching regular expression.

This option tells CTest to NOT run the tests whose labels match the given regular expression.  When more than one -LE option is given, a test will only be excluded if each regular expression matches at least one of the test's labels (i.e. the multiple -LE labels form an AND relationship).  See Label Matching.

--tests-from-file <filename>

Added in version 3.29.

Run tests listed in the given file.

This option tells CTest to run tests that are listed in the given file. The file must contain one exact test name per line. Lines that do not exactly match any test names are ignored. This option can be combined with the other options like -R, -E, -L or -LE.

--exclude-from-file <filename>

Added in version 3.29.

Exclude tests listed in the given file.

This option tells CTest to NOT run tests that are listed in the given file. The file must contain one exact test name per line. Lines that do not exactly match any test names are ignored. This option can be combined with the other options like -R, -E, -L or -LE.

-FA <regex>, --fixture-exclude-any <regex>

Exclude fixtures matching <regex> from automatically adding any tests to the test set.

If a test in the set of tests to be executed requires a particular fixture, that fixture's setup and cleanup tests would normally be added to the test set automatically. This option prevents adding setup or cleanup tests for fixtures matching the <regex>. Note that all other fixture behavior is retained, including test dependencies and skipping tests that have fixture setup tests that fail.

-FS <regex>, --fixture-exclude-setup <regex>

Same as -FA except only matching setup tests are excluded.

-FC <regex>, --fixture-exclude-cleanup <regex>

Same as -FA except only matching cleanup tests are excluded.

-I [Start,End,Stride,test#,test#|Test file], --tests-information

Run a specific number of tests by number.

This option causes CTest to run tests starting at number Start, ending at number End, and incrementing by Stride.  Any additional numbers after Stride are considered individual test numbers.  Start, End, or Stride can be empty.  Optionally a file can be given that contains the same syntax as the command line.

-U,  --union

Take the Union of -I and -R.

When both -R and -I are specified by default the intersection of tests are run.  By specifying -U the union of tests is run instead.

--rerun-failed

Run only the tests that failed previously.

This option tells CTest to perform only the tests that failed during its previous run.  When this option is specified, CTest ignores all other options intended to modify the list of tests to run ( -L, -R, -E, -LE, -I, etc).  In the event that CTest runs and no tests fail, subsequent calls to CTest with the --rerun-failed option will run the set of tests that most recently failed (if any).

--repeat <mode>:<n>

Run tests repeatedly based on the given <mode> up to <n> times. The modes are:

until-fail

Require each test to run <n> times without failing in order to pass. This is useful in finding sporadic failures in test cases.

until-pass

Allow each test to run up to <n> times in order to pass. Repeats tests if they fail for any reason. This is useful in tolerating sporadic failures in test cases.

after-timeout

Allow each test to run up to <n> times in order to pass. Repeats tests only if they timeout. This is useful in tolerating sporadic timeouts in test cases on busy machines.

--repeat-until-fail <n>

Equivalent to --repeat until-fail:<n>.

--max-width <width>

Set the max width for a test name to output.

Set the maximum width for each test name to show in the output. This allows the user to widen the output to avoid clipping the test name which can be very annoying.

--interactive-debug-mode [0|1]

Set the interactive mode to 0 or 1.

This option causes CTest to run tests in either an interactive mode or a non-interactive mode.  In dashboard mode (Experimental, Nightly, Continuous), the default is non-interactive.  In non-interactive mode, the environment variable DASHBOARD_TEST_FROM_CTEST is set.

Prior to CMake 3.11, interactive mode on Windows allowed system debug popup windows to appear.  Now, due to CTest's use of libuv to launch test processes, all system debug popup windows are always blocked.

--no-label-summary

Disable timing summary information for labels.

This option tells CTest not to print summary information for each label associated with the tests run.  If there are no labels on the tests, nothing extra is printed.

See Label and Subproject Summary.

--no-subproject-summary

Disable timing summary information for subprojects.

This option tells CTest not to print summary information for each subproject associated with the tests run.  If there are no subprojects on the tests, nothing extra is printed.

See Label and Subproject Summary.

--test-dir <dir>

Added in version 3.20.

Specify the directory in which to look for tests, typically a CMake project build directory. If not specified, the current directory is used.

--test-output-size-passed <size>

Added in version 3.4.

Limit the output for passed tests to <size> bytes.

--test-output-size-failed <size>

Added in version 3.4.

Limit the output for failed tests to <size> bytes.

--test-output-truncation <mode>

Added in version 3.24.

Truncate tail (default), middle or head of test output once maximum output size is reached.

--overwrite

Overwrite CTest configuration option.

By default CTest uses configuration options from configuration file. This option will overwrite the configuration option.

--force-new-ctest-process

Run child CTest instances as new processes.

By default CTest will run child CTest instances within the same process.  If this behavior is not desired, this argument will enforce new processes for child CTest processes.

--schedule-random

Use a random order for scheduling tests.

This option will run the tests in a random order.  It is commonly used to detect implicit dependencies in a test suite.

--submit-index

Legacy option for old Dart2 dashboard server feature. Do not use.

--timeout <seconds>

Set the default test timeout.

This option effectively sets a timeout on all tests that do not already have a timeout set on them via the TIMEOUT property.

--stop-time <time>

Set a time at which all tests should stop running.

Set a real time of day at which all tests should timeout.  Example: 7:00:00 -0400.  Any time format understood by the curl date parser is accepted.  Local time is assumed if no timezone is specified.

--print-labels

Print all available test labels.

This option will not run any tests, it will simply print the list of all labels associated with the test set.

--no-tests=<action>

Regard no tests found either as error (when <action> is set to error) or ignore it (when <action> is set to ignore).

If no tests were found, the default behavior of CTest is to always log an error message but to return an error code in script mode only.  This option unifies the behavior of CTest by either returning an error code if no tests were found or by ignoring it.

Added in version 3.26.

This option can also be set by setting the CTEST_NO_TESTS_ACTION environment variable.

To print version details or selected pages from the CMake documentation, use one of the following options:

-version [<file>], --version [<file>], /V [<file>]

Show program name/version banner and exit. The output is printed to a named <file> if given.

-h,  -H,  --help,  -help,  -usage, /?

Print usage information and exit.

Usage describes the basic command line interface and its options.

--help <keyword> [<file>]

Print help for one CMake keyword.

<keyword> can be a property, variable, command, policy, generator or module.

The relevant manual entry for <keyword> is printed in a human-readable text format. The output is printed to a named <file> if given.

Changed in version 3.28: Prior to CMake 3.28, this option supported command names only.

--help-full [<file>]

Print all help manuals and exit.

All manuals are printed in a human-readable text format. The output is printed to a named <file> if given.

--help-manual <man> [<file>]

Print one help manual and exit.

The specified manual is printed in a human-readable text format. The output is printed to a named <file> if given.

--help-manual-list [<file>]

List help manuals available and exit.

The list contains all manuals for which help may be obtained by using the --help-manual option followed by a manual name. The output is printed to a named <file> if given.

--help-command <cmd> [<file>]

Print help for one command and exit.

The cmake-commands(7) manual entry for <cmd> is printed in a human-readable text format. The output is printed to a named <file> if given.

--help-command-list [<file>]

List commands with help available and exit.

The list contains all commands for which help may be obtained by using the --help-command option followed by a command name. The output is printed to a named <file> if given.

--help-commands [<file>]

Print cmake-commands manual and exit.

The cmake-commands(7) manual is printed in a human-readable text format. The output is printed to a named <file> if given.

--help-module <mod> [<file>]

Print help for one module and exit.

The cmake-modules(7) manual entry for <mod> is printed in a human-readable text format. The output is printed to a named <file> if given.

--help-module-list [<file>]

List modules with help available and exit.

The list contains all modules for which help may be obtained by using the --help-module option followed by a module name. The output is printed to a named <file> if given.

--help-modules [<file>]

Print cmake-modules manual and exit.

The cmake-modules(7) manual is printed in a human-readable text format. The output is printed to a named <file> if given.

--help-policy <cmp> [<file>]

Print help for one policy and exit.

The cmake-policies(7) manual entry for <cmp> is printed in a human-readable text format. The output is printed to a named <file> if given.

--help-policy-list [<file>]

List policies with help available and exit.

The list contains all policies for which help may be obtained by using the --help-policy option followed by a policy name. The output is printed to a named <file> if given.

--help-policies [<file>]

Print cmake-policies manual and exit.

The cmake-policies(7) manual is printed in a human-readable text format. The output is printed to a named <file> if given.

--help-property <prop> [<file>]

Print help for one property and exit.

The cmake-properties(7) manual entries for <prop> are printed in a human-readable text format. The output is printed to a named <file> if given.

--help-property-list [<file>]

List properties with help available and exit.

The list contains all properties for which help may be obtained by using the --help-property option followed by a property name. The output is printed to a named <file> if given.

--help-properties [<file>]

Print cmake-properties manual and exit.

The cmake-properties(7) manual is printed in a human-readable text format. The output is printed to a named <file> if given.

--help-variable <var> [<file>]

Print help for one variable and exit.

The cmake-variables(7) manual entry for <var> is printed in a human-readable text format. The output is printed to a named <file> if given.

--help-variable-list [<file>]

List variables with help available and exit.

The list contains all variables for which help may be obtained by using the --help-variable option followed by a variable name. The output is printed to a named <file> if given.

--help-variables [<file>]

Print cmake-variables manual and exit.

The cmake-variables(7) manual is printed in a human-readable text format. The output is printed to a named <file> if given.

Tests may have labels attached to them. Tests may be included or excluded from a test run by filtering on the labels. Each individual filter is a regular expression applied to the labels attached to a test.

When -L is used, in order for a test to be included in a test run, each regular expression must match at least one label.  Using more than one -L option means "match all of these".

The -LE option works just like -L, but excludes tests rather than including them. A test is excluded if each regular expression matches at least one label.

If a test has no labels attached to it, then -L will never include that test, and -LE will never exclude that test. As an example of tests with labels, consider five tests, with the following labels:

• test1 has labels tuesday and production
• test2 has labels tuesday and test
• test3 has labels wednesday and production
• test4 has label wednesday
• test5 has labels friday and test

Running ctest with -L tuesday -L test will select test2, which has both labels. Running CTest with -L test will select test2 and test5, because both of them have a label that matches that regular expression.

Because the matching works with regular expressions, take note that running CTest with -L es will match all five tests. To select the tuesday and wednesday tests together, use a single regular expression that matches either of them, like -L "tue|wed".

CTest prints timing summary information for each LABEL and subproject associated with the tests run. The label time summary will not include labels that are mapped to subprojects.

Added in version 3.22: Labels added dynamically during test execution are also reported in the timing summary.  See Additional Labels.

When the PROCESSORS test property is set, CTest will display a weighted test timing result in label and subproject summaries. The time is reported with sec*proc instead of just sec.

The weighted time summary reported for each label or subproject j is computed as:

Weighted Time Summary for Label/Subproject j =
    sum(raw_test_time[j,i] * num_processors[j,i], i=1...num_tests[j])

for labels/subprojects j=1...total

where:

• raw_test_time[j,i]: Wall-clock time for the i test for the j label or subproject
• num_processors[j,i]: Value of the CTest PROCESSORS property for the i test for the j label or subproject
• num_tests[j]: Number of tests associated with the j label or subproject
• total: Total number of labels or subprojects that have at least one test run

Therefore, the weighted time summary for each label or subproject represents the amount of time that CTest gave to run the tests for each label or subproject and gives a good representation of the total expense of the tests for each label or subproject when compared to other labels or subprojects.

For example, if SubprojectA showed 100 sec*proc and SubprojectB showed 10 sec*proc, then CTest allocated approximately 10 times the CPU/core time to run the tests for SubprojectA than for SubprojectB (e.g. so if effort is going to be expended to reduce the cost of the test suite for the whole project, then reducing the cost of the test suite for SubprojectA would likely have a larger impact than effort to reduce the cost of the test suite for SubprojectB).

CTest provides a command-line signature to configure (i.e. run cmake on), build, and/or execute a test:

ctest --build-and-test <path-to-source> <path-to-build>
      --build-generator <generator>
      [<options>...]
      [--build-options <opts>...]
      [--test-command <command> [<args>...]]

The configure and test steps are optional. The arguments to this command line are the source and binary directories.  The --build-generator option must be provided to use --build-and-test.  If --test-command is specified then that will be run after the build is complete.  Other options that affect this mode include:

--build-and-test

Switch into the build and test mode.

--build-target

Specify a specific target to build.  The option can be given multiple times with different targets, in which case each target is built in turn. A clean will be done before building each target unless the --build-noclean option is given.

If no --build-target is specified, the all target is built.

--build-nocmake

Run the build without running cmake first.

Skip the cmake step.

--build-run-dir

Specify directory to run programs from.

Directory where programs will be after it has been compiled.

--build-two-config

Run CMake twice.

--build-exe-dir

Specify the directory for the executable.

--build-generator

Specify the generator to use. See the cmake-generators(7) manual.

--build-generator-platform

Specify the generator-specific platform.

--build-generator-toolset

Specify the generator-specific toolset.

--build-project

Specify the name of the project to build.

--build-makeprogram

Specify the explicit make program to be used by CMake when configuring and building the project. Only applicable for Make and Ninja based generators.

--build-noclean

Skip the make clean step.

--build-config-sample

A sample executable to use to determine the configuration that should be used.  e.g.  Debug, Release etc.

--build-options

Additional options for configuring the build (i.e. for CMake, not for the build tool).  Note that if this is specified, the --build-options keyword and its arguments must be the last option given on the command line, with the possible exception of --test-command.

--test-command

The command to run as the test step with the --build-and-test option. All arguments following this keyword will be assumed to be part of the test command line, so it must be the last option given.

--test-timeout

The time limit in seconds

CTest can operate as a client for the CDash software quality dashboard application.  As a dashboard client, CTest performs a sequence of steps to configure, build, and test software, and then submits the results to a CDash server. The command-line signature used to submit to CDash is:

ctest -D <dashboard>         [-- <dashboard-options>...]
ctest -M <model> -T <action> [-- <dashboard-options>...]
ctest -S <script>            [-- <dashboard-options>...]
ctest -SP <script>           [-- <dashboard-options>...]

Options for Dashboard Client include:

-D <dashboard>, --dashboard <dashboard>

Execute dashboard test.

This option tells CTest to act as a CDash client and perform a dashboard test.  All tests are <Mode><Test>, where <Mode> can be Experimental, Nightly, and Continuous, and <Test> can be Start, Update, Configure, Build, Test, Coverage, and Submit.

If <dashboard> is not one of the recognized <Mode><Test> values, this will be treated as a variable definition instead (see the dashboard-options further below).

-M <model>, --test-model <model>

Sets the model for a dashboard.

This option tells CTest to act as a CDash client where the <model> can be Experimental, Nightly, and Continuous. Combining -M and -T is similar to -D.

-T <action>, --test-action <action>

Sets the dashboard action to perform.

This option tells CTest to act as a CDash client and perform some action such as start, build, test etc. See Dashboard Client Steps for the full list of actions. Combining -M and -T is similar to -D.

-S <script>, --script <script>

Execute a dashboard for a configuration.

This option tells CTest to load in a configuration script which sets a number of parameters such as the binary and source directories. Then CTest will do what is required to create and run a dashboard. This option basically sets up a dashboard and then runs ctest -D with the appropriate options.

-SP <script>, --script-new-process <script>

Execute a dashboard for a configuration.

This option does the same operations as -S but it will do them in a separate process.  This is primarily useful in cases where the script may modify the environment and you do not want the modified environment to impact other -S scripts.

The available <dashboard-options> are the following:

-D <var>:<type>=<value>

Define a variable for script mode.

Pass in variable values on the command line.  Use in conjunction with -S to pass variable values to a dashboard script. Parsing -D arguments as variable values is only attempted if the value following -D does not match any of the known dashboard types.

--group <group>

Specify what group you'd like to submit results to

Submit dashboard to specified group instead of default one.  By default, the dashboard is submitted to Nightly, Experimental, or Continuous group, but by specifying this option, the group can be arbitrary.

This replaces the deprecated option --track. Despite the name change its behavior is unchanged.

-A <file>, --add-notes <file>

Add a notes file with submission.

This option tells CTest to include a notes file when submitting dashboard.

--tomorrow-tag

Nightly or Experimental starts with next day tag.

This is useful if the build will not finish in one day.

--extra-submit <file>[;<file>]

Submit extra files to the dashboard.

This option will submit extra files to the dashboard.

--http-header <header>

Added in version 3.29.

Append HTTP header when submitting to the dashboard.

This option will cause CTest to append the specified header when submitting to the dashboard. This option may be specified more than once.

--http1.0

Submit using HTTP 1.0.

This option will force CTest to use HTTP 1.0 to submit files to the dashboard, instead of HTTP 1.1.

--no-compress-output

Do not compress test output when submitting.

This flag will turn off automatic compression of test output.  Use this to maintain compatibility with an older version of CDash which doesn't support compressed test output.

ctest -D <mode>[<step>]
ctest -M <mode> [-T <step>]...

# Lines starting in '#' are comments.
# Other non-blank lines are key-value pairs.
<setting>: <value>

ctest -S <script>
ctest -SP <script>

The Dashboard Client Steps may be configured by named settings as documented in the following sections.

Added in version 3.14.

When the --show-only=json-v1 command line option is given, the test information is output in JSON format.  Version 1.0 of the JSON object model is defined as follows:

kind

The string "ctestInfo".

version

A JSON object specifying the version components.  Its members are

major

A non-negative integer specifying the major version component.

minor

A non-negative integer specifying the minor version component.

backtraceGraph

JSON object representing backtrace information with the following members:

commands

List of command names.

files

List of file names.

nodes

List of node JSON objects with members:

command

Index into the commands member of the backtraceGraph.

file

Index into the files member of the backtraceGraph.

line

Line number in the file where the backtrace was added.

parent

Index into the nodes member of the backtraceGraph representing the parent in the graph.

tests

A JSON array listing information about each test.  Each entry is a JSON object with members:

name

Test name.

config

Configuration that the test can run on. Empty string means any config.

command

List where the first element is the test command and the remaining elements are the command arguments.

backtrace

Index into the nodes member of the backtraceGraph.

properties

Test properties. Can contain keys for each of the supported test properties.

CTest provides a mechanism for tests to specify the resources that they need in a fine-grained way, and for users to specify the resources available on the running machine. This allows CTest to internally keep track of which resources are in use and which are free, scheduling tests in a way that prevents them from trying to claim resources that are not available.

When the resource allocation feature is used, CTest will not oversubscribe resources. For example, if a resource has 8 slots, CTest will not run tests that collectively use more than 8 slots at a time. This has the effect of limiting how many tests can run at any given time, even if a high -j argument is used, if those tests all use some slots from the same resource. In addition, it means that a single test that uses more of a resource than is available on a machine will not run at all (and will be reported as Not Run).

A common use case for this feature is for tests that require the use of a GPU. Multiple tests can simultaneously allocate memory from a GPU, but if too many tests try to do this at once, some of them will fail to allocate, resulting in a failed test, even though the test would have succeeded if it had the memory it needed. By using the resource allocation feature, each test can specify how much memory it requires from a GPU, allowing CTest to schedule tests in a way that running several of these tests at once does not exhaust the GPU's memory pool.

Please note that CTest has no concept of what a GPU is or how much memory it has. It does not have any way of communicating with a GPU to retrieve this information or perform any memory management, although the project can define a test that provides details about the test machine (see Dynamically-Generated Resource Specification File).

CTest keeps track of a list of abstract resource types, each of which has a certain number of slots available for tests to use. Each test specifies the number of slots that it requires from a certain resource, and CTest then schedules them in a way that prevents the total number of slots in use from exceeding the listed capacity. When a test is executed, and slots from a resource are allocated to that test, tests may assume that they have exclusive use of those slots for the duration of the test's process.

The CTest resource allocation feature consists of at least two inputs:

• The resource specification file, described below, which describes the resources available on the system.
• The RESOURCE_GROUPS property of tests, which describes the resources required by the test.

When CTest runs a test, the resources allocated to that test are passed in the form of a set of environment variables as described below. Using this information to decide which resource to connect to is left to the test writer.

The RESOURCE_GROUPS property tells CTest what resources a test expects to use grouped in a way meaningful to the test.  The test itself must read the environment variables to determine which resources have been allocated to each group.  For example, each group may correspond to a process the test will spawn when executed.

Note that even if a test specifies a RESOURCE_GROUPS property, it is still possible for that to test to run without any resource allocation (and without the corresponding environment variables) if the user does not pass a resource specification file. Passing this file, either through the --resource-spec-file command-line argument or the RESOURCE_SPEC_FILE argument to ctest_test(), is what activates the resource allocation feature. Tests should check the CTEST_RESOURCE_GROUP_COUNT environment variable to find out whether or not resource allocation is activated. This variable will always (and only) be defined if resource allocation is activated. If resource allocation is not activated, then the CTEST_RESOURCE_GROUP_COUNT variable will not exist, even if it exists for the parent ctest process. If a test absolutely must have resource allocation, then it can return a failing exit code or use the SKIP_RETURN_CODE or SKIP_REGULAR_EXPRESSION properties to indicate a skipped test.

{
  "version": {
    "major": 1,
    "minor": 0
  },
  "local": [
    {
      "gpus": [
        {
          "id": "0",
          "slots": 2
        },
        {
          "id": "1",
          "slots": 4
        },
        {
          "id": "2",
          "slots": 2
        },
        {
          "id": "3"
        }
      ],
      "crypto_chips": [
        {
          "id": "card0",
          "slots": 4
        }
      ]
    }
  ]
}

Added in version 3.29.

On POSIX systems, when running under the context of a Job Server, CTest shares its job slots.  This is independent of the PROCESSORS test property, which still counts against CTest's -j parallel level.  CTest acquires exactly one token from the job server before running each test, and returns it when the test finishes.

For example, consider the Makefile:

test:
	+ctest -j 8

When invoked via make -j 2 test, ctest connects to the job server, acquires a token for each test, and runs at most 2 tests concurrently.

On Windows systems, job server integration is not yet implemented.

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https://cmake.org/documentation

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https://discourse.cmake.org

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