Use one gtest lib for test subdirectories

tests/CMakeLists.txt

@@ -16,11 +16,13 @@
 #add_subdirectory(regression)
 
 # google test framework
-# This fails with lots of  undefined reference to `testing::UnitTest::Run()'
-#add_library(GTEST gtest-all.cpp gtest.h)
+add_library(gtest gtest-all.cpp)
+
+# tests look for gtest.h here
+include_directories(${CMAKE_CURRENT_SOURCE_DIR})
 
 # Unit tests
 add_subdirectory(unit)
 
 # Test validating models, possebly needing other software installed
-add_subdirectory(validation)
\ No newline at end of file
+add_subdirectory(validation)

tests/unit/CMakeLists.txt

@@ -8,9 +8,6 @@ set(HEADERS
     ${PROJECT_SOURCE_DIR}/src/tree.hpp
 )
 
-# google test framework
-add_library(gtest gtest-all.cpp gtest.h)
-
 set(TEST_SOURCES
     # unit tests
     test_algorithms.cpp

tests/validation/CMakeLists.txt

@@ -23,9 +23,6 @@ set(VALIDATION_SOURCES
     validate.cpp
 )
 
-# google test framework
-add_library(gtest_validate gtest-all.cpp gtest.h)
-
 add_definitions("-DDATADIR=\"${CMAKE_SOURCE_DIR}/data\"")
 
 add_executable(validate.exe ${VALIDATION_SOURCES} ${HEADERS})
@@ -33,7 +30,7 @@ add_executable(validate.exe ${VALIDATION_SOURCES} ${HEADERS})
 set(TARGETS validate.exe)
 
 foreach(target ${TARGETS})
-	target_link_libraries(${target} LINK_PUBLIC cellalgo gtest_validate)
+    target_link_libraries(${target} LINK_PUBLIC cellalgo gtest)
     
     if(WITH_TBB)
 	target_link_libraries(${target} LINK_PUBLIC ${TBB_LIBRARIES})