Run tests from root directory

.travis.yml

@@ -41,4 +41,4 @@ before_script:
 script:
   - ./tools/ci/travis-script.sh
 after_success:
-  - coveralls -d tests/.coverage
+  - coveralls

tools/ci/travis-script.sh

@@ -2,14 +2,13 @@
 set -ex
 
 # Run source check
-cd tests
 if [[ $TRAVIS_PYTHON_VERSION == "3.4" && $OMP == 'n' && $MPI == 'n' ]]; then
-    ./check_source.py
+    pushd tests && python check_source.py && popd
 fi
 
 # Run regression and unit tests
 if [[ $MPI == 'y' ]]; then
-    pytest --cov=../openmc -v --mpi
+    pytest --cov=openmc -v --mpi tests
 else
-    pytest --cov=../openmc -v
+    pytest --cov=openmc -v tests
 fi