My folder structure:

Project
|--Component1
       |------src/
               |----file.c
       |------hdr/
               |----file.h
       |------test/
                |---unittests.cpp (tests file.h)
                |---CMakeLists.txt (builds Component1UnitTests.a)
       CMakeLists.txt (builds Component1.a, includes test/CMakeLists.txt)
|--Component 2
       ...
       CMakeLists.txt
|--Test
     |--ProjectTests.cpp (only contains main-function with RUN_ALL_TESTS)
CMakeLists.txt (builds executable "Project" and links Component1.a, Component2.a, builds executable "ProjectTest" and links "Component1UnitTests.a", "Component2UnitTest.a")

The ProjectTests.cpp looks like this

#include <gtest/gtest.h>

int main(int argc, char **argv) {
    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}

The root-level CMakeLists.txt section about ProjectTest looks like this:

add_executable(ProjectTest ${CMAKE_CURRENT_SOURCE_DIR}/Test/ProjectTests.cpp)
target_link_libraries (ProjecTest PUBLIC "Component1UnitTests" GTest::gtest_main)

The CMakeLists.txt in Project/Component1/ looks like this:

add_library(Component1UnitTests ${CMAKE_CURRENT_SOURCE_DIR}/unittests.cpp)
target_sources(Component1UnitTests PUBLIC ${PROJECT_SOURCES})
target_include_directories(Component1UnitTests PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/../hdr)

Unfortunately this doesn’t work. If the resulting ProjectTest is executed, I get this console output:

[==========] Running 0 tests from 0 test suites.
[==========] 0 tests from 0 test suites ran. (0 ms total)
[  PASSED  ] 0 tests.

What am I doing wrong?