Fix tests' structure, code style and use of GTest

tests/CMakeLists.txt

@@ -5,17 +5,21 @@ endif()
 add_subdirectory(simple_library)
 add_subdirectory(simple_executable)
 
-add_executable(AppDirUnitTests AppDirUnitTests.cpp)
-target_link_libraries(AppDirUnitTests PRIVATE linuxdeploy_core)
-target_include_directories(AppDirUnitTests PRIVATE ${PROJECT_SOURCE_DIR}/include)
+add_executable(test_appdir test_appdir.cpp)
+target_link_libraries(test_appdir PRIVATE linuxdeploy_core gtest)
+target_include_directories(test_appdir PRIVATE ${PROJECT_SOURCE_DIR}/include)
 
-target_compile_definitions(AppDirUnitTests PRIVATE
+# calculate paths to resources using CMake and hardcode them in the test binary
+target_compile_definitions(test_appdir PRIVATE
     -DSIMPLE_LIBRARY_PATH="$<TARGET_FILE:simple_library>"
     -DSIMPLE_EXECUTABLE_PATH="$<TARGET_FILE:simple_executable>"
     -DSIMPLE_DESKTOP_ENTRY_PATH="${CMAKE_CURRENT_SOURCE_DIR}/data/simple_app.Desktop"
     -DSIMPLE_ICON_PATH="${CMAKE_CURRENT_SOURCE_DIR}/data/simple_icon.svg"
     -DSIMPLE_FILE_PATH="${CMAKE_CURRENT_SOURCE_DIR}/data/simple_file.txt"
-    )
+)
 
-add_gtest(AppDirUnitTests)
-add_dependencies(AppDirUnitTests simple_library simple_executable)
+# register in CTest
+add_test(test_appdir test_appdir)
+
+# make sure library and executable are built before test_appdir
+add_dependencies(test_appdir simple_library simple_executable)

tests/simple_executable/simple_executable.cpp

@@ -1,6 +1,5 @@
 #include <cstdio>
-
-extern "C" { void hello_world(); }
+#include <simple_library.h>
 
 int main() {
     printf("Hello World");

tests/simple_library/CMakeLists.txt

@@ -1,2 +1,3 @@
-add_library(simple_library SHARED simple_library.cpp)
-target_link_libraries(simple_library CImg)
+add_library(simple_library SHARED simple_library.cpp simple_library.h)
+target_link_libraries(simple_library PUBLIC CImg)
+target_include_directories(simple_library PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})

tests/simple_library/simple_library.cpp

@@ -1,8 +1,6 @@
 #include "CImg.h"
 using namespace cimg_library;
 
-extern "C" {
 void hello_world() {
     cimg::info();
 }
-}

tests/simple_library/simple_library.h

@@ -0,0 +1 @@
+void hello_world();

tests/test_appdir.cpp

@@ -3,9 +3,9 @@
 
 using namespace linuxdeploy::core::appdir;
 using namespace linuxdeploy::core::desktopfile;
-
 using namespace boost::filesystem;
-namespace AppDirUnitTests {
+
+namespace AppDirTest {
     class AppDirUnitTestsFixture : public ::testing::Test {
     public:
         AppDirUnitTestsFixture() :
@@ -176,3 +176,8 @@ namespace AppDirUnitTests {
             FAIL();
     }
 }
+
+int main(int argc, char **argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}