diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 7730d4b572b701094b69b95277d964e824eb3d8e..b32a166506354b75b643f234c1416739a855e416 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -14,13 +14,13 @@ before_script:
   - virtualenv venv
   - source venv/bin/activate
   - pip3 install .
-  # - pip3 install .[tests]
+  - pip3 install .[tests]
 
 linters:
   script:
     - pip3 install .[linters]
     - make check
 
-#tests:
-#  script:
-#    - pytest tests
+tests:
+  script:
+    - pytest tests
diff --git a/Makefile b/Makefile
index 2afe68fa59506787df0741deb455249010d773f9..7caa8be84371ffb57cbca5327872859817eea403 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-SOURCES=losscalculator setup.py
+SOURCES=losscalculator tests setup.py
 LENGTH=96
 
 check: $(SOURCES)
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..529feb33dc59a579cf9957692d24c5e46be178e7
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1,17 @@
+#!/usr/bin/python3
+
+# Copyright (c) 2020:
+#  Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or (at
+# your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero
+# General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
diff --git a/tests/test_lossCalculator.py b/tests/test_lossCalculator.py
new file mode 100644
index 0000000000000000000000000000000000000000..e7340cc4281d644fde5f89003742907fe5cc4b33
--- /dev/null
+++ b/tests/test_lossCalculator.py
@@ -0,0 +1,25 @@
+#!/usr/bin/python3
+
+# Copyright (c) 2020:
+#  Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or (at
+# your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero
+# General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
+
+import logging
+
+logger = logging.getLogger()
+
+
+def test_func():
+    pass