How to add a CMake custom target to test all sub-projects?

Question

I have a repository with several projects inside. The resulting directory structure is like this :

Repository
  --CMakeLists.txt
  --Project A
      --CMakeLists.txt
  --Project B
      --CMakeLists.txt

In projects A and B I have tests that I add using add_test. When inside a project I can do make test.

How can I add a target "test" to the top CMakeLists.txt to be able to call make test from the top directory and get the tests of all projects executed ?

Answer 1

I have just tried to reproduce your setup with the following files:

/tmp/test $ tree
.
├── a
│   └── CMakeLists.txt
├── b
│   └── CMakeLists.txt
└── CMakeLists.txt

/tmp/test $ cat CMakeLists.txt 
cmake_minimum_required(VERSION 3.0)

project(Foo)

enable_testing()
add_subdirectory(a)
add_subdirectory(b)
/tmp/test $ cat a/CMakeLists.txt 
project(A)
add_test(NAME atest COMMAND echo "hello from a")
/tmp/test $ cat b/CMakeLists.txt 
project(B)
add_test(NAME btest COMMAND echo "hello from b")

/tmp/test/build $ mkdir build && cd build
/tmp/test/build $ cmake .. && make test
# Remove some output
Running tests...
Test project /tmp/test/build
    Start 1: atest
1/2 Test #1: atest ............................   Passed    0.00 sec
    Start 2: btest
2/2 Test #2: btest ............................   Passed    0.00 sec