Add approximate linear energy gradient regression test #92 #74

	name: Coverage
	on: [push, pull_request]
	jobs:
	Coverage:
	runs-on: ubuntu-20.04
	steps:
	- name: Clone NiftyReg
	uses: actions/checkout@v3

	- name: Install Catch2
	run: \|
	git clone https://github.com/catchorg/Catch2.git
	cd Catch2
	cmake -Bbuild -H. -DBUILD_TESTING=OFF
	sudo cmake --build build/ --target install --config Debug

	- name: Install lcov
	run: sudo apt-get install lcov

	- name: Configure NiftyReg
	run: \|
	mkdir build
	cd build
	cmake -DCMAKE_CXX_COMPILER=g++ \
	-DCMAKE_C_COMPILER=gcc \
	-DCMAKE_BUILD_TYPE=Debug \
	-DBUILD_ALL_DEP=ON \
	-DUSE_CUDA=OFF \
	-DUSE_OPENCL=OFF \
	-DUSE_SSE=ON \
	-DUSE_OPENMP=OFF \
	-DBUILD_TESTING=ON \
	-DWITH_COVERAGE=ON \
	..

	- name: Build NiftyReg
	run: cmake --build build --config Debug

	- name: Run tests
	run: ctest -V
	working-directory: build

	- name: Coverage
	run: make coverage
	working-directory: build

	- name: Upload coverage to Coveralls
	uses: coverallsapp/github-action@v1
	with:
	path-to-lcov: build/coverage.info

Provide feedback