diff --git a/shared/utils/tests/check_env_test.py b/shared/utils/tests/check_env_test.py
new file mode 100644
index 0000000..32ec322
--- /dev/null
+++ b/shared/utils/tests/check_env_test.py
@@ -0,0 +1,53 @@
+"""Definition of tests for check_env function."""
+
+import os
+import unittest
+
+from shared.utils import check_env
+
+
+class TestFunctionCheckEnv(unittest.TestCase):
+    """Testing function check_env."""
+
+    def setUp(self):
+        """Prepare for tests."""
+        # define variables for test
+        self.not_set_env_var = 'NOT_SET_ENV_VAR'
+        self.set_env_var_map = {
+            'ENV_VAR_UPPER': 'ENV_VAR_UPPER',
+            'ENV_VAR_LOWER': 'env_var_lower',
+        }
+        # set env vars
+        for key, val in self.set_env_var_map.items():
+            os.environ[key] = val
+
+    def tearDown(self):
+        """Clean up after tests."""
+        # remove env vars
+        for key in self.set_env_var_map:
+            _ = os.environ.pop(key, default=None)
+
+    def test_input_type(self):
+        """Test that function fails on wrong input types."""
+        with self.assertRaises(AssertionError):
+            check_env('not_a_list')
+        with self.assertRaises(AssertionError):
+            check_env({1, 2, 3})
+
+    def test_env_var_not_set(self):
+        """Test that function raises AssertionError when checking environment
+        variable that is not set."""
+        var_list = {self.not_set_env_var}
+        msg = f'environment variable not set: {self.not_set_env_var}'
+        with self.assertRaises(AssertionError, msg=msg):
+            check_env(var_list)
+
+    def test_env_vars_set(self):
+        """Test that function does not raise any errors when environment
+        variables are set."""
+        var_list = set(self.set_env_var_map.keys())
+        check_env(var_list)
+
+
+if __name__ == '__main__':
+    unittest.main()