Add CI, including compiling gtest

.gitlab-ci.yml

+# use MPCDF module environment
+image: gitlab-registry.mpcdf.mpg.de/mpcdf/module-image
+
+default:
+  before_script:
+    - module load cmake git
+
+test-gcc9:
+  script:
+    - module load gcc/9
+    - CC=gcc CXX=g++ CXXFLAGS="-std=c++11" ./get_gtest.sh
+    - make CC=gcc CXX=g++ CXXFLAGS="-std=c++11 -I$PWD/googletest/install/include" LDFLAGS="-L$PWD/googletest/install/lib64"
+
+test-intel19:
+  script:
+    - module load intel/19.0.4
+    - CC=icc CXX=icpc CXXFLAGS="-std=c++11" ./get_gtest.sh
+    - make CC=icc CXX=icpc CXXFLAGS="-std=c++11 -I$PWD/googletest/install/include" LDFLAGS="-L$PWD/googletest/install/lib64"

Makefile

 SRC=src/main.cpp
-TESTS=tests
 COV=coverage
 OUT_T=test_output
 OUT_E=expected_output
 APP=program
 CXX=g++
 BROWSER=google-chrome
+TESTS=tests
+TEST_APP=runTests
+TEST_SRC=$(TESTS)/test_funcs.cpp
+LDFLAGS_GTEST=-lgtest -lpthread
 
 # Default
 all: distclean compile test
 
 # Compiling section
 compile:
-	$(CXX) -o $(APP) $(SRC)
+	$(CXX) $(CXXFLAGS) -o $(APP) $(SRC)
 
 compile_coverage:
-	$(CXX) -o $(APP) --coverage $(SRC)
+	$(CXX) $(CXXFLAGS) -o $(APP) --coverage $(SRC)
 
 # Testing section
 test: simple_tests regression_test unit_tests
@@ -31,8 +34,9 @@ regression_test:
 	diff $(OUT_T) $(OUT_E)
 
 unit_tests:
-	cd $(TESTS) && cmake CMakeLists.txt && make
-	./$(TESTS)/runTests
+	$(CXX) $(CXXFLAGS) -o test_funcs.o -c $(TEST_SRC)
+	$(CXX) $(CXXFLAGS) test_funcs.o -o $(TEST_APP) $(LDFLAGS) $(LDFLAGS_GTEST)
+	./$(TEST_APP)
 
 # Coverage section
 coverage: clean clean_coverage compile_coverage simple_tests
@@ -50,7 +54,7 @@ clean:
 	rm -f $(APP)
 
 clean_tests:
-	rm -rf $(TESTS)/CMakeFiles $(TESTS)/CMakeCache.txt $(TESTS)/cmake_install.cmake $(TESTS)/CMakeFiles $(TESTS)/runTests $(OUT_E) $(OUT_T)
+	rm -rf $(TESTS)/CMakeFiles $(TESTS)/CMakeCache.txt $(TESTS)/cmake_install.cmake $(TESTS)/CMakeFiles $(TESTS)/runTests $(OUT_E) $(OUT_T) $(TEST_APP) *.o
 
 clean_coverage:
 	rm -rf *.gcno *.gcda $(APP).info $(COV)

get_gtest.sh

+#!/bin/bash
+
+# already there
+[[ -d googletest ]] && exit 0
+
+# otherwise download and build
+git clone https://github.com/google/googletest.git
+mkdir -p googletest/build
+cd googletest/build
+cmake .. -DCMAKE_INSTALL_PREFIX=../install
+make && make install