diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 4073ebc..9adadbd 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -4,12 +4,14 @@ run tests:
   script:
     - pip install pytest pytest-cov pytest-mock pytest-flask
     - pip install Flask-HTTPAuth
-    - coverage run -m pytest
+    - coverage run -m pytest --junitxml=report.xml
     - coverage report
     - coverage xml
   coverage: '/^TOTAL.+?(\d+\%)$/'
   artifacts:
+    when: always
     reports:
       cobertura: coverage.xml
+      junit: report.xml
   tags:
     - docker
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..9866aab
--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+[![pipeline status](https://gitlab.niet.verweg.com/ruben/jail2ban-pf/badges/main/pipeline.svg)](https://gitlab.niet.verweg.com/ruben/jail2ban-pf/-/commits/main)
+[![coverage report](https://gitlab.niet.verweg.com/ruben/jail2ban-pf/badges/main/coverage.svg)](https://gitlab.niet.verweg.com/ruben/jail2ban-pf/-/commits/main)
+
diff --git a/jail2ban/__init__.py b/jail2ban/__init__.py
index 9d43d7f..889963d 100644
--- a/jail2ban/__init__.py
+++ b/jail2ban/__init__.py
@@ -5,6 +5,7 @@ from ipaddress import ip_address
 import re
 from jail2ban.pfctl import pfctl_table_op, pfctl_cfg_read, pfctl_cfg_write
 from jail2ban.auth import get_users
+from subprocess import CalledProcessError
 
 
 auth = HTTPBasicAuth()
@@ -26,15 +27,11 @@ def untaint(pattern, string):
         raise ValueError(f'"{string}" is tainted')
 
 
-def create_app(config=None):
+def create_app():
     app = Flask(__name__, instance_relative_config=True)
 
-    if config is None:
-        # load the instance config, if it exists, when not testing
-        app.config.from_pyfile('config.py', silent=True)
-    else:
-        # load the test config if passed in
-        app.config.from_pyfile(config, silent=True)
+    # load the instance config, if it exists, when not testing
+    app.config.from_pyfile('config.py', silent=True)
 
     @auth.verify_password
     def verify_password(username, password):
@@ -58,7 +55,7 @@ def create_app(config=None):
         return jsonify({'anchor': f'f2b-jail/{remote_user}',
                         'table': f'f2b-{name}',
                         'operation': 'flush',
-                        'result': res})
+                        'result': [x.decode('ascii') for x in res]})
 
     @app.route("/register", methods=['PUT', 'DELETE'])
     @auth.login_required
@@ -80,7 +77,7 @@ def create_app(config=None):
                 ])
             res = pfctl_cfg_write(f'f2b-jail/{remote_user}',
                                   b'\n'.join(cfg) + b'\n')
-        elif request.method == 'DELETE':
+        else:  # 'DELETE':
             cfg = [cfg_line for cfg_line in cfg
                    if cfg_line.find(bytes(f'<f2b-{name}>', 'ascii')) == -1]
             res = pfctl_cfg_write(f'f2b-jail/{remote_user}',
@@ -92,12 +89,11 @@ def create_app(config=None):
                            table=f'f2b-{name}',
                            operation='kill')
         app.logger.info(f'pfctl -a f2b-jail/{remote_user} -f-')
-        return jsonify({'remote_user': remote_user, 'data': data})
         return jsonify({'anchor': f'f2b-jail/{remote_user}',
                         'table': f'f2b-{name}',
                         'action': 'start' if request.method == 'PUT'
                         else 'stop',
-                        'result': res})
+                        'result': [x.decode('ascii') for x in res]})
 
     @app.route("/ban", methods=['PUT', 'DELETE'])
     @auth.login_required
@@ -114,7 +110,7 @@ def create_app(config=None):
                                  table=f'f2b-{name}',
                                  operation='add',
                                  value=str(ip))
-        elif request.method == 'DELETE':
+        else:  # 'DELETE':
             app.logger.info(f'Remove {ip} from f2b-{name}'
                             f' in anchor f2b-jail/{remote_user}')
             res = pfctl_table_op(f'f2b-jail/{remote_user}',
@@ -135,6 +131,22 @@ def create_app(config=None):
         app.logger.fatal(error)
         return jsonify({'error': str(error)}), 500
 
+    @app.errorhandler(CalledProcessError)
+    def subprocess_err(error):
+        '''
+        Show a json parsable error if the value is illegal
+        '''
+        app.logger.fatal(error)
+        return jsonify({'error': str(error)}), 500
+
+    @app.errorhandler(FileNotFoundError)
+    def filenotfound_err(error):
+        '''
+        Show a json parsable error if the value is illegal
+        '''
+        app.logger.fatal(error)
+        return jsonify({'error': str(error)}), 500
+
     @auth.error_handler
     def auth_error():
         app.logger.error('Access Denied')
diff --git a/jail2ban/auth.py b/jail2ban/auth.py
index d9867bf..8b4b1b4 100644
--- a/jail2ban/auth.py
+++ b/jail2ban/auth.py
@@ -1,18 +1,15 @@
-from flask import current_app, g
-import os
+from flask import current_app
 
 
 def get_users():
-    if 'users' not in g:
-        users = {}
-        authfile = current_app.config['AUTHFILE']
+    users = {}
+    authfile = current_app.config['AUTHFILE']
 
-        current_app.logger.debug('Reading %s for users', authfile)
+    current_app.logger.debug('Reading %s for users', authfile)
 
-        with current_app.open_resource(os.path.join("..",
-                                                    authfile)) as f:
-            for entry in f:
-                users.update({tuple(entry.decode('ascii').strip().split(':', 1))})
-            g.users = users
-    current_app.logger.debug(g.users)
-    return g.users
+    with current_app.open_resource(authfile) as f:
+        for entry in f:
+            users.update({
+                tuple(entry.decode('ascii').strip().split(':', 1))})
+    current_app.logger.debug(users)
+    return users
diff --git a/jail2ban/pfctl.py b/jail2ban/pfctl.py
index 4a079e7..0e062c5 100644
--- a/jail2ban/pfctl.py
+++ b/jail2ban/pfctl.py
@@ -9,12 +9,10 @@ def pfctl_cfg_read(anchor):
     cmd = [_SUDO, _PFCTL, '-a', anchor, '-sr']
     logging.info('Running %s', cmd)
 
-    res = run(cmd, capture_output=True)
+    res = run(cmd, capture_output=True, check=True)
 
-    if res and res.stdout:
-        logging.info('Result: %s', res)
-        res.check_returncode()
-        return res.stdout.splitlines()
+    logging.info('Result: %s', res)
+    return res.stdout.splitlines()
 
 
 def pfctl_cfg_write(anchor, cfg):
@@ -24,12 +22,11 @@ def pfctl_cfg_write(anchor, cfg):
 
     res = run(cmd,
               input=cfg,
+              check=True,
               capture_output=True)
 
-    if res:
-        logging.info('Result: %s', res)
-        res.check_returncode()
-        return res
+    logging.info('Result: %s', res)
+    return res.stdout.splitlines()
 
 
 def pfctl_table_op(anchor, **kwargs):
@@ -40,9 +37,9 @@ def pfctl_table_op(anchor, **kwargs):
 
     logging.info('Running %s', cmd)
 
-    res = run([x for x in cmd if x is not None], capture_output=True)
+    res = run([x for x in cmd if x is not None],
+              capture_output=True,
+              check=True)
 
-    if res:
-        logging.debug(res)
-        res.check_returncode()
-        return res.stdout.splitlines()
+    logging.debug(res)
+    return res.stdout.splitlines()
diff --git a/tests/conftest.py b/tests/conftest.py
index 2ebdf68..4adf233 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,4 +1,5 @@
 import pytest
+import base64
 from jail2ban import create_app
 
 
@@ -8,7 +9,7 @@ def app():
     app.config.update({
         "TESTING": True,
         "SECRET_KEY": 'Testing',
-        "AUTHFILE": 'tests/users-test.txt'
+        "AUTHFILE": '../tests/users-test.txt'
     })
 
     # other setup can go here
@@ -26,3 +27,8 @@ def client(app):
 @pytest.fixture()
 def runner(app):
     return app.test_cli_runner()
+
+
+@pytest.fixture()
+def valid_credentials():
+    return base64.b64encode(b"test.example.com:testpassword").decode("utf-8")
diff --git a/tests/test_ban.py b/tests/test_ban.py
new file mode 100644
index 0000000..a2553f2
--- /dev/null
+++ b/tests/test_ban.py
@@ -0,0 +1,102 @@
+from types import SimpleNamespace
+
+
+def test_ban_ipv6(client, mocker, valid_credentials):
+    def noop():
+        pass
+    run_res = SimpleNamespace()
+    run_res.stdout = b''
+    run_res.stderr = b'1/1 addresses added.\n'
+    run_res.returncode = 0
+    run_res.check_returncode = noop
+
+    mocker.patch('jail2ban.pfctl.run', return_value=run_res)
+
+    json_payload = {"name": "sshd", "ip": "2001:db8::abad:cafe"}
+    response = client.put("/ban",
+                          json=json_payload,
+                          headers={"Authorization":
+                                   "Basic " + valid_credentials})
+
+    assert response.json['operation'] == 'add'
+
+
+def test_ban_ipv4(client, mocker, valid_credentials):
+    def noop():
+        pass
+    run_res = SimpleNamespace()
+    run_res.stdout = b''
+    run_res.stderr = b'1/1 addresses added.\n'
+    run_res.returncode = 0
+    run_res.check_returncode = noop
+
+    mocker.patch('jail2ban.pfctl.run', return_value=run_res)
+
+    json_payload = {"name": "sshd", "ip": "192.0.2.42"}
+    response = client.put("/ban",
+                          json=json_payload,
+                          headers={"Authorization":
+                                   "Basic " + valid_credentials})
+
+    assert response.json['operation'] == 'add'
+
+
+def test_ban_invalid(client, mocker, valid_credentials):
+    def noop():
+        pass
+    run_res = SimpleNamespace()
+    run_res.stdout = b''
+    run_res.stderr = b'1/1 addresses added.\n'
+    run_res.returncode = 0
+    run_res.check_returncode = noop
+
+    mocker.patch('jail2ban.pfctl.run', return_value=run_res)
+
+    json_payload = {"name": "sshd", "ip": "not:an::addr:ess"}
+    response = client.put("/ban",
+                          json=json_payload,
+                          headers={"Authorization":
+                                   "Basic " + valid_credentials})
+
+    assert response.json['error'] == "'not:an::addr:ess' does not " \
+                                     "appear to be an IPv4 or IPv6 address"
+
+
+def test_unban_ipv6(client, mocker, valid_credentials):
+    def noop():
+        pass
+    run_res = SimpleNamespace()
+    run_res.stdout = b''
+    run_res.stderr = b'1/1 addresses deleted.\n'
+    run_res.returncode = 0
+    run_res.check_returncode = noop
+
+    mocker.patch('jail2ban.pfctl.run', return_value=run_res)
+
+    json_payload = {"name": "sshd", "ip": "2001:db8::abad:cafe"}
+    response = client.delete("/ban",
+                             json=json_payload,
+                             headers={"Authorization":
+                                      "Basic " + valid_credentials})
+
+    assert response.json['operation'] == 'delete'
+
+
+def test_unban_ipv4(client, mocker, valid_credentials):
+    def noop():
+        pass
+    run_res = SimpleNamespace()
+    run_res.stdout = b''
+    run_res.stderr = b'1/1 addresses deleted.\n'
+    run_res.returncode = 0
+    run_res.check_returncode = noop
+
+    mocker.patch('jail2ban.pfctl.run', return_value=run_res)
+
+    json_payload = {"name": "sshd", "ip": "192.0.2.42"}
+    response = client.delete("/ban",
+                             json=json_payload,
+                             headers={"Authorization":
+                                      "Basic " + valid_credentials})
+
+    assert response.json['operation'] == 'delete'
diff --git a/tests/test_flush.py b/tests/test_flush.py
new file mode 100644
index 0000000..9ac64ba
--- /dev/null
+++ b/tests/test_flush.py
@@ -0,0 +1,77 @@
+from types import SimpleNamespace
+from subprocess import CalledProcessError
+
+
+def test_flush(client, mocker, valid_credentials):
+    def noop():
+        pass
+    run_res = SimpleNamespace()
+    run_res.stdout = b''
+    run_res.stderr = b'1/1 addresses deleted.\n'
+    run_res.returncode = 0
+    run_res.check_returncode = noop
+
+    mocker.patch('jail2ban.pfctl.run', return_value=run_res)
+
+    name = 'sshd'
+    response = client.get(f"/flush/{name}",
+                          headers={"Authorization":
+                                   "Basic " + valid_credentials})
+
+    assert response.json['operation'] == 'flush'
+
+
+def test_flush_nonexistent(client, mocker, valid_credentials):
+
+    cmd = ['/usr/local/bin/sudo',
+           '/sbin/pfctl', '-a', 'some/anchor',
+           '-t', 'nonexistent', '-T', 'flush']
+
+    side_effect = CalledProcessError(255, cmd, output=b'',
+                                     stderr=b'pfctl: Table does not exist')
+
+    mocker.patch('jail2ban.pfctl.run',
+                 side_effect=side_effect)
+
+    name = 'nonexistent'
+    response = client.get(f"/flush/{name}",
+                          headers={"Authorization":
+                                   "Basic " + valid_credentials})
+
+    assert 'error' in response.json
+
+
+def test_wrong_method(client, mocker, valid_credentials):
+
+    cmd = ['/usr/local/bin/sudo',
+           '/sbin/pfctl', '-a', 'some/anchor',
+           '-t', 'nonexistent', '-T', 'flush']
+
+    side_effect = CalledProcessError(255, cmd, output=b'',
+                                     stderr=b'pfctl: Table does not exist')
+
+    mocker.patch('jail2ban.pfctl.run',
+                 side_effect=side_effect)
+
+    name = 'nonexistent'
+    response = client.put(f"/flush/{name}",
+                          headers={"Authorization":
+                                   "Basic " + valid_credentials})
+
+    assert response.status_code == 405
+
+
+def test_filenotfound(app, mocker, valid_credentials):
+
+    app.config.update({
+        "AUTHFILE": '../tests/nonexistent-users-test.txt'
+    })
+
+    client = app.test_client()
+
+    name = 'nonexistent'
+    response = client.get(f"/flush/{name}",
+                          headers={"Authorization":
+                                   "Basic " + valid_credentials})
+
+    assert response.status_code == 500
diff --git a/tests/test_register.py b/tests/test_register.py
index b061ad6..9312d09 100644
--- a/tests/test_register.py
+++ b/tests/test_register.py
@@ -1,5 +1,4 @@
-import base64
-from types import SimpleNamespace
+from subprocess import CompletedProcess
 
 pfctl_stdout_lines = b'''
 block drop quick proto tcp from <f2b-sendmail-auth> to any port = submission
@@ -7,31 +6,108 @@ block drop quick proto tcp from <f2b-sendmail-auth> to any port = smtps
 block drop quick proto tcp from <f2b-sendmail-auth> to any port = smtp
 block drop quick proto tcp from <f2b-sshd> to any port = ssh
 block drop quick proto tcp from <f2b-recidive> to any
-'''
+'''.strip() + b'\n'
+
+pfctl_stdout_lines_scratch = b'table <f2b-dovecot> persist counters\n' \
+                             b'block quick proto tcp from <f2b-dovecot>' \
+                             b' to any port ' \
+                             b'{pop3,pop3s,imap,imaps,submission,465,sieve}\n'
 
 
-def test_request_unauth(client):
-    json_payload = {"port": "any port {pop3,pop3s,imap,imaps,submission,465,sieve}", "name": "dovecot", "protocol": "tcp"}
+def test_register_unauth(client):
+    json_payload = {"port":
+                    "any port {pop3,pop3s,imap,imaps,submission,465,sieve}",
+                    "name": "dovecot", "protocol": "tcp"}
     response = client.put("/register", json=json_payload)
 
     assert response.json['error'] == 'Access Denied'
 
 
-def test_request_example(client, mocker):
+def test_unregister_valid(client, mocker, valid_credentials):
     def noop():
         pass
-    run_res = SimpleNamespace()
+    run_res = CompletedProcess(args=['true'], returncode=0)
     run_res.stdout = pfctl_stdout_lines
     run_res.check_returncode = noop
 
     mocker.patch('jail2ban.pfctl.run', return_value=run_res)
 
+    json_payload = {"port":
+                    "any port {pop3,pop3s,imap,imaps,submission,465,sieve}",
+                    "name": "dovecot", "protocol": "tcp"}
+
+    response = client.delete("/register",
+                             json=json_payload,
+                             headers={"Authorization":
+                                      "Basic " + valid_credentials})
+
+    assert response.json['action'] == 'stop'
+
+
+def test_register_valid(client, mocker, valid_credentials):
+    def noop():
+        pass
+    run_res = CompletedProcess(args=['true'], returncode=0)
+    run_res.stdout = pfctl_stdout_lines
+    run_res.check_returncode = noop
+
+    pfctl_run = mocker.patch('jail2ban.pfctl.run', return_value=run_res)
+
+    json_payload = {"port":
+                    "any port {pop3,pop3s,imap,imaps,submission,465,sieve}",
+                    "name": "dovecot", "protocol": "tcp"}
 
-    valid_credentials = base64.b64encode(b"test.example.com:testpassword").decode("utf-8")
-    json_payload = {"port": "any port {pop3,pop3s,imap,imaps,submission,465,sieve}", "name": "dovecot", "protocol": "tcp"}
     response = client.put("/register",
                           json=json_payload,
-                          headers={"Authorization": "Basic " + valid_credentials})
+                          headers={"Authorization":
+                                   "Basic " + valid_credentials})
+
+    pfctl_run_input_arg = pfctl_run.call_args_list[1][1]['input']
+    for existing_line in pfctl_stdout_lines.splitlines():
+        assert existing_line in pfctl_run_input_arg.splitlines()
+
+    assert response.json['action'] == 'start'
 
 
-    assert response.json['remote_user'] == 'test.example.com'
+def test_register_valid_from_scratch(client, mocker, valid_credentials):
+    def noop():
+        pass
+    run_res = CompletedProcess(args=['true'], returncode=0)
+    run_res.stdout = b''
+    run_res.check_returncode = noop
+
+    pfctl_run = mocker.patch('jail2ban.pfctl.run', return_value=run_res)
+
+    json_payload = {"port":
+                    "any port {pop3,pop3s,imap,imaps,submission,465,sieve}",
+                    "name": "dovecot", "protocol": "tcp"}
+
+    response = client.put("/register",
+                          json=json_payload,
+                          headers={"Authorization":
+                                   "Basic " + valid_credentials})
+
+    pfctl_run_input_arg = pfctl_run.call_args_list[1][1]['input']
+    assert pfctl_run_input_arg == pfctl_stdout_lines_scratch
+    assert response.json['action'] == 'start'
+
+
+def test_register_invalid(client, mocker, valid_credentials):
+    def noop():
+        pass
+    run_res = CompletedProcess(args=['true'], returncode=0)
+    run_res.stdout = pfctl_stdout_lines
+    run_res.check_returncode = noop
+
+    mocker.patch('jail2ban.pfctl.run', return_value=run_res)
+
+    json_payload = {"port":
+                    "not a pf statement",
+                    "name": "dovecot", "protocol": "tcp"}
+
+    response = client.put("/register",
+                          json=json_payload,
+                          headers={"Authorization":
+                                   "Basic " + valid_credentials})
+
+    assert response.json['error'] == '"not a pf statement" is tainted'