A CMake module containing a collection of assertion functions and other utilities for testing CMake code.
The main feature of this module is the assert
function, which asserts the
given condition in the style of CMake's
if
function. If the
assertion fails, it throws a fatal error message with information about the
context of the asserted condition.
This module also supports
CMake test
creation using the assertion_add_test
function. This function creates a new
test that processes the given file in script mode with variables, functions, and
macros from this module available in the test file.
If this module is processed in script mode, it can optionally include other
modules by passing their paths as additional arguments after --
.
- Supports condition, fatal error, and process execution assertions.
- Supports test creation that processes a CMake file.
- Simple syntax and easy integration.
The recommended way to integrate this module into a project is by downloading it
during the project configuration using the
file(DOWNLOAD)
function:
file(DOWNLOAD https://github.com/threeal/assertion-cmake/releases/download/v1.0.0/Assertion.cmake
${CMAKE_BINARY_DIR}/Assertion.cmake)
include(${CMAKE_BINARY_DIR}/Assertion.cmake)
Alternatively, to support offline mode, this module can also be vendored
directly into a project and included normally using the include
function.
There are three functions provided by this module that can be used to perform assertions in CMake code:
assert
: Performs an assertion on the given condition.assert_fatal_error
: Performs an assertion on whether the given call throws a fatal error.assert_execute_process
: Performs an assertion on whether the given command correctly executes a process.
For example, given the following git_clone
function for cloning a Git
repository from the given URL
and setting the OUTPUT_VAR
with the path of
the cloned Git repository directory:
function(git_clone URL OUTPUT_VAR)
string(REGEX REPLACE ".*/" "" DIRECTORY "${URL}")
execute_process(
COMMAND git clone "${URL}" "${DIRECTORY}"
RESULT_VARIABLE RES)
if(NOT RES EQUAL 0)
message(FATAL_ERROR "failed to clone '${URL}' (${RES})")
endif()
set("${OUTPUT_VAR}" "${DIRECTORY}" PARENT_SCOPE)
endfunction()
You can create the following assertions to verify if it can successfully clone a Git repository and correctly set the output variable:
git_clone(https://github.com/threeal/cmake-starter CMAKE_STARTER_DIR)
assert(DEFINED CMAKE_STARTER_DIR)
assert(EXISTS "${CMAKE_STARTER_DIR}")
You can further verify if the output variable contains a correct Git directory and if it correctly throws a fatal error message on failure:
assert(IS_DIRECTORY "${CMAKE_STARTER_DIR}")
assert_execute_process(
git -C "${CMAKE_STARTER_DIR}" rev-parse --is-inside-work-tree)
assert_fatal_error(
CALL git_clone https://github.com GITHUB_DIR
MESSAGE "failed to clone 'https://github.com'")
In CMake, tests are normally created using the add_test
function and run
separately from the project configuration and build processes. To simplify test
creation, this module provides an assertion_add_test
function.
Given a file named git_checkout_test.cmake
that contains assertions for a
git_clone
function, you can create a new test target that will process that
file as follows:
assertion_add_test(git_checkout_test.cmake NAME "Git check out test")
The above line creates a new test target named "Git check out test" that will
process the git_checkout_test.cmake
file in script mode with assertion
functions already declared, eliminating the need to include this module inside
the git_checkout_test.cmake
file.
This variable contains the path to the included Assertion.cmake
module.
Adds a new test that processes the given CMake file in script mode.
assertion_add_test(<file> [NAME <name>])
This function adds a new test that processes the given <file>
in script mode.
If NAME
is specified, it will use <name>
as the test name; otherwise, it
will use <file>
.
Internally, the test will process the Assertion.cmake
module in script mode
and include the given <file>
at the end of the module, allowing variables,
functions, and macros in the Assertion.cmake
module to be available in the
<file>
without the need to include the Assertion.cmake
module from the
<file>
.
assertion_add_test(test/first_test.cmake)
assertion_add_test(test/second_test.cmake NAME "Second Test")
The above example adds two new tests. The first one is named
test/first_test.cmake
, which will process the file with the same name as the
test. The second one is named Second Test
, which will process the
test/second_test.cmake
file.
Throws a formatted fatal error message.
fail(<lines>...)
This macro throws a fatal error message formatted from the given <lines>
.
It formats the message by concatenating all the lines into a single message. If one of the lines is a variable, it will be expanded and indented by two spaces before being concatenated with the other lines. If the expanded variable is another variable, it will format both the name and the value of the other variable.
set(COMMAND "some_command arg0 arg1 arg2")
set(REASON "some reason")
fail("something happened when executing" COMMAND "because of" REASON)
The above example throws a fatal error message formatted as follows:
something happened when executing:
some_command arg0 arg1 arg2
because of:
some reason
Asserts the given condition.
assert(<condition>...)
This function performs an assertion on the given <condition>
. If the assertion
fails, it will output a formatted fatal error message with information about the
context of the asserted condition.
Internally, this function uses CMake's if
function to check the given
condition and throws a fatal error message if the condition resolves to false.
Refer to the
CMake's if
function documentation
for more information about supported conditions for the assertion.
assert(DEFINED EXECUTABLE_PATH)
assert(IS_EXECUTABLE "${EXECUTABLE_PATH}")
The above example asserts whether the EXECUTABLE_PATH
variable is defined and
resolves to the path of an executable. If the variable is not defined, it will
throw the following fatal error message:
expected variable:
EXECUTABLE_PATH
to be defined
Asserts whether a command call throws a fatal error message.
assert_fatal_error(CALL <command> [<arguments>...] MESSAGE <message>...)
This function asserts whether a function or macro named <command>
, called with
the specified <arguments>
, throws a fatal error message that matches the
expected <message>
.
If more than one <message>
string is given, they are concatenated into a
single message with no separator between the strings.
function(throw_fatal_error MESSAGE)
message(FATAL_ERROR "${MESSAGE}")
endfunction()
assert_fatal_error(
CALL throw_fatal_error "some message"
MESSAGE "some message")
The above example asserts whether the call to
throw_fatal_error("some message")
throws a fatal error message that matches
some message
. If it somehow does not capture any fatal error message, it will
throw the following fatal error message:
expected to receive a fatal error message that matches:
some message
Asserts whether the given command correctly executes a process.
assert_execute_process(
[COMMAND] <command> [<arguments>...]
[OUTPUT <output>...]
[ERROR <error>...])
This function asserts whether the given <command>
and <arguments>
successfully execute a process. If ERROR
is specified, it instead asserts
whether it fails to execute the process.
If OUTPUT
is specified, it also asserts whether the output of the executed
process matches the expected <output>
. If more than one <output>
string is
given, they are concatenated into a single output with no separator between the
strings.
If ERROR
is specified, it also asserts whether the error of the executed
process matches the expected <error>
. If more than one <error>
string is
given, they are concatenated into a single error with no separator between the
strings.
assert_execute_process(
COMMAND ${CMAKE_COMMAND} -E echo hello
OUTPUT hello)
The above example asserts whether the call to ${CMAKE_COMMAND} -E echo hello
successfully executes a process whose output matches hello
. If it somehow
fails to execute the process, it will throw the following fatal error message:
expected command:
${CMAKE_COMMAND} -E echo hello
not to fail with error:
unknown error
Begins a new test section.
section(<name>...)
This function begins a new test section named <name>
. It prints the test
section name and indents all subsequent messages by two spaces.
If more than one <name>
string is given, they are concatenated into a single
name with no separator between the strings.
Use the endsection
function to end the test section.
section("test something")
section("it should not fail")
message(STATUS "nothing happened")
endsection()
section("it should fail" " because something might happen")
fail("something happened")
endsection()
endsection()
The above example begins several test sections. If processed, it will output the following lines:
-- test something
-- it should not fail
-- nothing happened
-- it should fail because something might happen
CMake Error (message):
something happened
Ends the current test section.
endsection()
This function ends the current test section.
This project is licensed under the terms of the MIT License.
Copyright © 2024 Alfi Maulana