diff --git a/app/Dockerfile b/app/Dockerfile
index 90e8b0e..300c1e0 100644
--- a/app/Dockerfile
+++ b/app/Dockerfile
@@ -62,18 +62,10 @@ RUN python -m pip install --no-cache --no-index /root/wheels/* && \
 COPY --chmod=0700 entrypoint.sh /root/entrypoint.sh
 COPY config .
 COPY src .
-RUN echo ${VERSION} > /proxy-version.txt
-RUN date > /build-date.txt
+RUN echo ${VERSION} > /proxy-version.txt \
+  && date > /build-date.txt
 EXPOSE 5005 8127 10000
 
 # command to run on container start
 ENTRYPOINT ["/root/entrypoint.sh"]
 CMD [ "python3", "./server.py" ]
-
-
-LABEL org.opencontainers.image.title="TSUN Gen3 Proxy"
-LABEL org.opencontainers.image.authors="Stefan Allius"
-LABEL org.opencontainers.image.source=https://github.com/s-allius/tsun-gen3-proxy
-LABEL org.opencontainers.image.description='This proxy enables a reliable connection between TSUN third generation inverters (eg. TSOL MS600, MS800, MS2000) and an MQTT broker to integrate the inverter into typical home automations.'
-LABEL org.opencontainers.image.licenses="BSD-3-Clause"
-LABEL org.opencontainers.image.vendor="Stefan Allius"
diff --git a/app/build.sh b/app/build.sh
index 7d66c91..ac1c23c 100755
--- a/app/build.sh
+++ b/app/build.sh
@@ -17,6 +17,7 @@ VERSION="${VERSION:1}"
 arr=(${VERSION//./ })
 MAJOR=${arr[0]}
 IMAGE=tsun-gen3-proxy
+
 GREEN='\033[0;32m'
 BLUE='\033[0;34m'
 NC='\033[0m'
@@ -26,44 +27,22 @@ IMAGE=docker.io/sallius/${IMAGE}
 VERSION=${VERSION}+$1
 elif [[ $1 == rc ]] || [[ $1 == rel ]] || [[ $1 == preview ]] ;then
 IMAGE=ghcr.io/s-allius/${IMAGE}
+echo 'login to ghcr.io'    
+echo $GHCR_TOKEN | docker login ghcr.io -u s-allius --password-stdin
 else
 echo argument missing!
 echo try: $0 '[debug|dev|preview|rc|rel]'
 exit 1
 fi
 
-if [[ $1 == debug ]] ;then
-BUILD_ENV="dev"
-else
-BUILD_ENV="production"
-fi
-
-BUILD_CMD="buildx build --push --build-arg VERSION=${VERSION} --build-arg environment=${BUILD_ENV} --attest type=provenance,mode=max --attest type=sbom,generator=docker/scout-sbom-indexer:latest"
-ARCH="--platform linux/amd64,linux/arm64,linux/arm/v7"
-LABELS="--label org.opencontainers.image.created=${BUILD_DATE} --label org.opencontainers.image.version=${VERSION} --label org.opencontainers.image.revision=${BRANCH}"
+export IMAGE
+export VERSION
+export BUILD_DATE
+export BRANCH
+export MAJOR
 
 echo version: $VERSION  build-date: $BUILD_DATE   image: $IMAGE
-if [[ $1 == debug ]];then
-docker ${BUILD_CMD} ${ARCH} ${LABELS} --build-arg "LOG_LVL=DEBUG" -t ${IMAGE}:debug  app
-
-elif [[ $1 == dev ]];then
-docker ${BUILD_CMD} ${ARCH} ${LABELS} -t ${IMAGE}:dev app
-
-elif [[ $1 == preview ]];then
-echo 'login to ghcr.io'    
-echo $GHCR_TOKEN | docker login ghcr.io -u s-allius --password-stdin
-docker ${BUILD_CMD} ${ARCH} ${LABELS} -t ${IMAGE}:preview -t ${IMAGE}:${VERSION} app
-
-elif [[ $1 == rc ]];then
-echo 'login to ghcr.io'    
-echo $GHCR_TOKEN | docker login ghcr.io -u s-allius --password-stdin
-docker ${BUILD_CMD} ${ARCH} ${LABELS} -t ${IMAGE}:rc -t ${IMAGE}:${VERSION} app
-
-elif [[ $1 == rel ]];then
-echo 'login to ghcr.io'    
-echo $GHCR_TOKEN | docker login ghcr.io -u s-allius --password-stdin
-docker ${BUILD_CMD} ${ARCH} ${LABELS} --no-cache -t ${IMAGE}:latest -t ${IMAGE}:${MAJOR} -t ${IMAGE}:${VERSION} app
-fi
+docker buildx bake -f app/docker-bake.hcl $1
 
 echo -e "${BLUE} => checking docker-compose.yaml file${NC}"
 docker-compose config -q
diff --git a/app/docker-bake.hcl b/app/docker-bake.hcl
new file mode 100644
index 0000000..b6d58d9
--- /dev/null
+++ b/app/docker-bake.hcl
@@ -0,0 +1,93 @@
+variable "IMAGE" {
+    default = "tsun-gen3-proxy"
+}
+variable "VERSION" {
+    default = "0.0.0"
+}
+variable "MAJOR" {
+    default = "0"
+}
+variable "BUILD_DATE" {
+    default = "dev"
+}
+variable "BRANCH" {
+    default = ""
+}
+variable "DESCRIPTION" {
+    default = "This proxy enables a reliable connection between TSUN third generation inverters (eg. TSOL MS600, MS800, MS2000) and an MQTT broker to integrate the inverter into typical home automations."
+}
+
+target "_common" {
+  context = "app"
+  dockerfile = "Dockerfile"
+  args = {
+    VERSION = "${VERSION}"
+    environment = "production"
+  }
+  attest = [
+    "type =provenance,mode=max",
+    "type =sbom,generator=docker/scout-sbom-indexer:latest"
+  ]
+  annotations = [
+    "index:org.opencontainers.image.title=TSUN Gen3 Proxy",
+    "index:org.opencontainers.image.authors=Stefan Allius",
+    "index:org.opencontainers.image.created=${BUILD_DATE}",
+    "index:org.opencontainers.image.version=${VERSION}",
+    "index:org.opencontainers.image.revision=${BRANCH}",
+    "index:org.opencontainers.image.description=${DESCRIPTION}",
+    "index:org.opencontainers.image.licenses=BSD-3-Clause",
+    "index:org.opencontainers.image.source=https://github.com/s-allius/tsun-gen3-proxy"
+  ]
+  labels = {
+    "org.opencontainers.image.title" = "TSUN Gen3 Proxy"
+    "org.opencontainers.image.authors" = "Stefan Allius"
+    "org.opencontainers.image.created" = "${BUILD_DATE}"
+    "org.opencontainers.image.version" = "${VERSION}"
+    "org.opencontainers.image.revision" = "${BRANCH}"
+    "org.opencontainers.image.description" = "${DESCRIPTION}"
+    "org.opencontainers.image.licenses" = "BSD-3-Clause"
+    "org.opencontainers.image.source" = "https://github.com/s-allius/tsun-gen3-proxy"
+  }
+  output = [
+    "type=image,push=true"
+  ]
+
+  no-cache = false
+  platforms = ["linux/amd64", "linux/arm64", "linux/arm/v7"]
+}
+
+target "_debug" {
+  args = {
+    LOG_LVL = "DEBUG"
+    environment = "dev"
+  }
+}
+target "_prod" {
+  args = {
+  }
+}
+target "debug" {
+  inherits = ["_common", "_debug"]
+  tags = ["${IMAGE}:debug"]
+}
+
+target "dev" {
+  inherits = ["_common"]
+  tags = ["${IMAGE}:dev"]
+}
+
+target "preview" {
+  inherits = ["_common", "_prod"]
+  tags = ["${IMAGE}:dev", "${IMAGE}:${VERSION}"]
+}
+
+target "rc" {
+  inherits = ["_common", "_prod"]
+  tags = ["${IMAGE}:rc", "${IMAGE}:${VERSION}"]
+}
+
+target "rel" {
+  inherits = ["_common", "_prod"]
+  tags = ["${IMAGE}:latest", "${IMAGE}:${MAJOR}", "${IMAGE}:${VERSION}"]
+  no-cache = true
+}
diff --git a/app/src/async_stream.py b/app/src/async_stream.py
index f6b58b5..5892ba2 100644
--- a/app/src/async_stream.py
+++ b/app/src/async_stream.py
@@ -3,10 +3,15 @@ import logging
 import traceback
 import time
 from asyncio import StreamReader, StreamWriter
-from messages import hex_dump_memory, State
 from typing import Self
 from itertools import count
 
+if __name__ == "app.src.async_stream":
+    from app.src.messages import hex_dump_memory, State
+else:  # pragma: no cover
+    from messages import hex_dump_memory, State
+
+
 import gc
 logger = logging.getLogger('conn')
 
diff --git a/app/src/gen3plus/connection_g3p.py b/app/src/gen3plus/connection_g3p.py
index 6591110..dc4eca1 100644
--- a/app/src/gen3plus/connection_g3p.py
+++ b/app/src/gen3plus/connection_g3p.py
@@ -1,7 +1,12 @@
 import logging
 from asyncio import StreamReader, StreamWriter
-from async_stream import AsyncStream
-from gen3plus.solarman_v5 import SolarmanV5
+
+if __name__ == "app.src.gen3plus.connection_g3p":
+    from app.src.async_stream import AsyncStream
+    from app.src.gen3plus.solarman_v5 import SolarmanV5
+else:  # pragma: no cover
+    from async_stream import AsyncStream
+    from gen3plus.solarman_v5 import SolarmanV5
 
 logger = logging.getLogger('conn')
 
diff --git a/app/src/gen3plus/inverter_g3p.py b/app/src/gen3plus/inverter_g3p.py
index 6c1d6b5..d9bf0f2 100644
--- a/app/src/gen3plus/inverter_g3p.py
+++ b/app/src/gen3plus/inverter_g3p.py
@@ -3,11 +3,18 @@ import traceback
 import json
 import asyncio
 from asyncio import StreamReader, StreamWriter
-from config import Config
-from inverter import Inverter
-from gen3plus.connection_g3p import ConnectionG3P
 from aiomqtt import MqttCodeError
-from infos import Infos
+
+if __name__ == "app.src.gen3plus.inverter_g3p":
+    from app.src.config import Config
+    from app.src.inverter import Inverter
+    from app.src.gen3plus.connection_g3p import ConnectionG3P
+    from app.src.infos import Infos
+else:  # pragma: no cover
+    from config import Config
+    from inverter import Inverter
+    from gen3plus.connection_g3p import ConnectionG3P
+    from infos import Infos
 
 
 logger_mqtt = logging.getLogger('mqtt')
diff --git a/app/src/gen3plus/solarman_v5.py b/app/src/gen3plus/solarman_v5.py
index 0cbdfab..94089f3 100644
--- a/app/src/gen3plus/solarman_v5.py
+++ b/app/src/gen3plus/solarman_v5.py
@@ -172,7 +172,7 @@ class SolarmanV5(Message):
         self.db.set_db_def_value(Register.POLLING_INTERVAL,
                                  self.mb_timeout)
         self.db.set_db_def_value(Register.HEARTBEAT_INTERVAL,
-                                 120)  # fixme
+                                 120)
         self.new_data['controller'] = True
 
         self.state = State.up
diff --git a/app/src/inverter.py b/app/src/inverter.py
index cf20c96..996fa0f 100644
--- a/app/src/inverter.py
+++ b/app/src/inverter.py
@@ -1,11 +1,15 @@
 import asyncio
 import logging
 import json
-from config import Config
-from mqtt import Mqtt
-from infos import Infos
+if __name__ == "app.src.inverter":
+    from app.src.config import Config
+    from app.src.mqtt import Mqtt
+    from app.src.infos import Infos
+else:  # pragma: no cover
+    from config import Config
+    from mqtt import Mqtt
+    from infos import Infos
 
-# logger = logging.getLogger('conn')
 logger_mqtt = logging.getLogger('mqtt')
 
 
@@ -72,7 +76,7 @@ class Inverter():
             Infos.new_stat_data[key] = False
 
     @classmethod
-    def class_close(cls, loop) -> None:
+    def class_close(cls, loop) -> None:   # pragma: no cover
         logging.debug('Inverter.class_close')
         logging.info('Close MQTT Task')
         loop.run_until_complete(cls.mqtt.close())
diff --git a/app/src/modbus_tcp.py b/app/src/modbus_tcp.py
index 5116bc8..a06e38f 100644
--- a/app/src/modbus_tcp.py
+++ b/app/src/modbus_tcp.py
@@ -1,9 +1,13 @@
 import logging
 import traceback
 import asyncio
-from config import Config
 
-from gen3plus.inverter_g3p import InverterG3P
+if __name__ == "app.src.modbus_tcp":
+    from app.src.config import Config
+    from app.src.gen3plus.inverter_g3p import InverterG3P
+else:  # pragma: no cover
+    from config import Config
+    from gen3plus.inverter_g3p import InverterG3P
 
 logger = logging.getLogger('conn')
 
diff --git a/app/tests/test_infos_g3.py b/app/tests/test_infos_g3.py
index e811d90..37a8076 100644
--- a/app/tests/test_infos_g3.py
+++ b/app/tests/test_infos_g3.py
@@ -325,7 +325,11 @@ def test_build_ha_conf1(contr_data_seq):
 
     assert tests==4
 
+def test_build_ha_conf2(contr_data_seq):
+    i = InfosG3()
+    i.static_init()                # initialize counter
 
+    tests = 0
     for d_json, comp, node_id, id in i.ha_proxy_confs(ha_prfx="tsun/", node_id = 'proxy/', snr = '456'):
 
         if id == 'out_power_123':
@@ -344,9 +348,9 @@ def test_build_ha_conf1(contr_data_seq):
             assert  d_json == json.dumps({"name": "Active Inverter Connections", "stat_t": "tsun/proxy/proxy", "dev_cla": None, "stat_cla": None, "uniq_id": "inv_count_456", "val_tpl": "{{value_json['Inverter_Cnt'] | int}}", "ic": "mdi:counter", "dev": {"name": "Proxy", "sa": "Proxy", "mdl": "proxy", "mf": "Stefan Allius", "sw": "unknown", "ids": ["proxy"]}, "o": {"name": "proxy", "sw": "unknown"}})
             tests +=1
 
-    assert tests==5
+    assert tests==1
 
-def test_build_ha_conf2(contr_data_seq, inv_data_seq, inv_data_seq2):
+def test_build_ha_conf3(contr_data_seq, inv_data_seq, inv_data_seq2):
     i = InfosG3()
     for key, result in i.parse (contr_data_seq):
         pass  # side effect in calling i.parse()
@@ -397,12 +401,9 @@ def test_must_incr_total(inv_data_seq2, inv_data_seq2_zero):
     assert json.dumps(i.db['env']) == json.dumps({"Inverter_Temp": 23})
     tests = 0
     for key, update in i.parse (inv_data_seq2):
-        if key == 'total':
+        if key == 'total' or key == 'env':
             assert update == False
             tests +=1   
-        elif key == 'env':
-            assert update == False
-            tests +=1
 
     assert tests==3
     assert json.dumps(i.db['total']) == json.dumps({'Daily_Generation': 1.7, 'Total_Generation': 17.36})
@@ -442,12 +443,9 @@ def test_must_incr_total2(inv_data_seq2, inv_data_seq2_zero):
     
     tests = 0
     for key, update in i.parse (inv_data_seq2_zero):
-        if key == 'total':
+        if key == 'total' or key == 'env':
             assert update == False
             tests +=1   
-        elif key == 'env':
-            assert update == False
-            tests +=1
 
     assert tests==3
     assert json.dumps(i.db['total']) == json.dumps({})
@@ -456,12 +454,9 @@ def test_must_incr_total2(inv_data_seq2, inv_data_seq2_zero):
 
     tests = 0
     for key, update in i.parse (inv_data_seq2):
-        if key == 'total':
+        if key == 'total' or key == 'env':
             assert update == True
             tests +=1   
-        elif key == 'env':
-            assert update == True
-            tests +=1
 
     assert tests==3
     assert json.dumps(i.db['total']) == json.dumps({'Daily_Generation': 1.7, 'Total_Generation': 17.36})
diff --git a/app/tests/test_infos_g3p.py b/app/tests/test_infos_g3p.py
index 21ef570..f7aef4d 100644
--- a/app/tests/test_infos_g3p.py
+++ b/app/tests/test_infos_g3p.py
@@ -1,18 +1,33 @@
 
 # test_with_pytest.py
-import pytest, json, math
+import pytest, json, math, random
 from app.src.infos import Register
 from app.src.gen3plus.infos_g3p import InfosG3P
 from app.src.gen3plus.infos_g3p import RegisterMap
 
+@pytest.fixture(scope="session")
+def str_test_ip():
+    ip =  ".".join(str(random.randint(1, 254)) for _ in range(4))
+    print(f'random_ip: {ip}')
+    return ip
+
+@pytest.fixture(scope="session")
+def bytes_test_ip(str_test_ip):
+    ip =  bytes(str.encode(str_test_ip))
+    l = len(ip)
+    if l < 16:
+        ip = ip + bytearray(16-l)
+    print(f'random_ip: {ip}')
+    return ip
+
 @pytest.fixture
-def device_data(): # 0x4110 ftype: 0x02
+def device_data(bytes_test_ip): # 0x4110 ftype: 0x02
     msg  = b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\xba\xd2\x00\x00'
     msg += b'\x19\x00\x00\x00\x00\x00\x00\x00\x05\x3c\x78\x01\x64\x01\x4c\x53'
     msg += b'\x57\x35\x42\x4c\x45\x5f\x31\x37\x5f\x30\x32\x42\x30\x5f\x31\x2e'
     msg += b'\x30\x35\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
-    msg += b'\x00\x00\x00\x00\x00\x00\x40\x2a\x8f\x4f\x51\x54\x31\x39\x32\x2e'
-    msg += b'\x31\x36\x38\x2e\x38\x30\x2e\x34\x39\x00\x00\x00\x0f\x00\x01\xb0'
+    msg += b'\x00\x00\x00\x00\x00\x00\x40\x2a\x8f\x4f\x51\x54' + bytes_test_ip
+    msg += b'\x0f\x00\x01\xb0'
     msg += b'\x02\x0f\x00\xff\x56\x31\x2e\x31\x2e\x30\x30\x2e\x30\x42\x00\x00'
     msg += b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
     msg += b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xfe\xfe\x00\x00'
@@ -63,14 +78,14 @@ def test_default_db():
         "collector": {"Chip_Type": "IGEN TECH"},
         })
 
-def test_parse_4110(device_data: bytes):
+def test_parse_4110(str_test_ip, device_data: bytes):
     i = InfosG3P(client_mode=False)
     i.db.clear()
     for key, update in i.parse (device_data, 0x41, 2):
         pass  # side effect is calling generator i.parse()
 
     assert json.dumps(i.db) == json.dumps({
-        'controller': {"Data_Up_Interval": 300, "Collect_Interval": 1, "Heartbeat_Interval": 120, "Signal_Strength": 100, "IP_Address": "192.168.80.49", "Sensor_List": "02b0"},
+        'controller': {"Data_Up_Interval": 300, "Collect_Interval": 1, "Heartbeat_Interval": 120, "Signal_Strength": 100, "IP_Address": str_test_ip, "Sensor_List": "02b0"},
         'collector': {"Chip_Model": "LSW5BLE_17_02B0_1.05", "Collector_Fw_Version": "V1.1.00.0B"},
         })
 
@@ -139,7 +154,11 @@ def test_build_ha_conf1():
 
     assert tests==7
 
+def test_build_ha_conf2():
+    i = InfosG3P(client_mode=False)
+    i.static_init()                # initialize counter
 
+    tests = 0
     for d_json, comp, node_id, id in i.ha_proxy_confs(ha_prfx="tsun/", node_id = 'proxy/', snr = '456'):
 
         if id == 'out_power_123':
@@ -161,9 +180,9 @@ def test_build_ha_conf1():
             assert  d_json == json.dumps({"name": "Active Inverter Connections", "stat_t": "tsun/proxy/proxy", "dev_cla": None, "stat_cla": None, "uniq_id": "inv_count_456", "val_tpl": "{{value_json['Inverter_Cnt'] | int}}", "ic": "mdi:counter", "dev": {"name": "Proxy", "sa": "Proxy", "mdl": "proxy", "mf": "Stefan Allius", "sw": "unknown", "ids": ["proxy"]}, "o": {"name": "proxy", "sw": "unknown"}})
             tests +=1
 
-    assert tests==8
+    assert tests==1
 
-def test_build_ha_conf2():
+def test_build_ha_conf3():
     i = InfosG3P(client_mode=True)
     i.static_init()                # initialize counter
 
@@ -209,7 +228,11 @@ def test_build_ha_conf2():
 
     assert tests==7
 
+def test_build_ha_conf4():
+    i = InfosG3P(client_mode=True)
+    i.static_init()                # initialize counter
 
+    tests = 0
     for d_json, comp, node_id, id in i.ha_proxy_confs(ha_prfx="tsun/", node_id = 'proxy/', snr = '456'):
 
         if id == 'out_power_123':
@@ -231,7 +254,7 @@ def test_build_ha_conf2():
             assert  d_json == json.dumps({"name": "Active Inverter Connections", "stat_t": "tsun/proxy/proxy", "dev_cla": None, "stat_cla": None, "uniq_id": "inv_count_456", "val_tpl": "{{value_json['Inverter_Cnt'] | int}}", "ic": "mdi:counter", "dev": {"name": "Proxy", "sa": "Proxy", "mdl": "proxy", "mf": "Stefan Allius", "sw": "unknown", "ids": ["proxy"]}, "o": {"name": "proxy", "sw": "unknown"}})
             tests +=1
 
-    assert tests==8
+    assert tests==1
 
 def test_exception_and_eval(inverter_data: bytes):
 
diff --git a/app/tests/test_inverter.py b/app/tests/test_inverter.py
new file mode 100644
index 0000000..40b23bf
--- /dev/null
+++ b/app/tests/test_inverter.py
@@ -0,0 +1,90 @@
+# test_with_pytest.py
+import pytest
+import asyncio
+import aiomqtt
+import logging
+
+from mock import patch, Mock
+from app.src.singleton import Singleton
+from app.src.inverter import Inverter
+from app.src.mqtt import Mqtt
+from app.src.gen3plus.solarman_v5 import SolarmanV5
+from app.src.config import Config
+
+
+pytest_plugins = ('pytest_asyncio',)
+
+
+@pytest.fixture(scope="module", autouse=True)
+def module_init():
+    def new_init(cls, cb_mqtt_is_up):
+        cb_mqtt_is_up()
+
+    Singleton._instances.clear()
+    with patch.object(Mqtt, '__init__', new_init):
+        yield
+
+@pytest.fixture(scope="module")
+def test_port():
+    return 1883
+
+@pytest.fixture(scope="module")
+def test_hostname():
+    # if getenv("GITHUB_ACTIONS") == "true":
+    #     return 'mqtt'
+    # else:
+        return 'test.mosquitto.org'
+
+@pytest.fixture
+def config_conn(test_hostname, test_port):
+    Config.act_config = {
+                        'mqtt':{
+                            'host': test_hostname,
+                            'port': test_port,
+                            'user': '',
+                            'passwd': ''
+                        },
+                        'ha':{
+                            'auto_conf_prefix': 'homeassistant',
+                            'discovery_prefix': 'homeassistant', 
+                            'entity_prefix': 'tsun',
+                            'proxy_node_id': 'test_1',
+                            'proxy_unique_id': ''
+                        },
+                        'inverters': {
+                            'allow_all': True,
+                            "R170000000000001":{
+                                'node_id': 'inv_1'
+                            }
+                        }
+    }
+
+@pytest.mark.asyncio
+async def test_inverter_cb(config_conn):
+    _ = config_conn
+
+    with patch.object(Inverter, '_cb_mqtt_is_up', wraps=Inverter._cb_mqtt_is_up) as spy:
+        print('call Inverter.class_init')
+        Inverter.class_init()
+        assert 'homeassistant/' == Inverter.discovery_prfx
+        assert 'tsun/' == Inverter.entity_prfx
+        assert 'test_1/' == Inverter.proxy_node_id
+        spy.assert_called_once()
+
+@pytest.mark.asyncio
+async def test_mqtt_is_up(config_conn):
+    _ = config_conn
+
+    with patch.object(Mqtt, 'publish') as spy:
+        Inverter.class_init()
+        await Inverter._cb_mqtt_is_up()
+        spy.assert_called()
+
+@pytest.mark.asyncio
+async def test_mqtt_proxy_statt_invalid(config_conn):
+    _ = config_conn
+
+    with patch.object(Mqtt, 'publish') as spy:
+        Inverter.class_init()
+        await Inverter._async_publ_mqtt_proxy_stat('InValId_kEy')
+        spy.assert_not_called()
diff --git a/app/tests/test_modbus_tcp.py b/app/tests/test_modbus_tcp.py
new file mode 100644
index 0000000..7792894
--- /dev/null
+++ b/app/tests/test_modbus_tcp.py
@@ -0,0 +1,78 @@
+# test_with_pytest.py
+import pytest
+import asyncio
+
+from mock import patch
+from app.src.singleton import Singleton
+from app.src.config import Config
+from app.src.infos import Infos
+from app.src.modbus_tcp import ModbusConn
+
+
+pytest_plugins = ('pytest_asyncio',)
+
+# initialize the proxy statistics
+Infos.static_init()
+
+@pytest.fixture(scope="module", autouse=True)
+def module_init():
+    Singleton._instances.clear()
+    yield
+
+@pytest.fixture(scope="module")
+def test_port():
+    return 1883
+
+@pytest.fixture(scope="module")
+def test_hostname():
+    # if getenv("GITHUB_ACTIONS") == "true":
+    #     return 'mqtt'
+    # else:
+        return 'test.mosquitto.org'
+
+@pytest.fixture
+def config_mqtt_conn(test_hostname, test_port):
+    Config.act_config = {'mqtt':{'host': test_hostname, 'port': test_port, 'user': '', 'passwd': ''},
+                         'ha':{'auto_conf_prefix': 'homeassistant','discovery_prefix': 'homeassistant', 'entity_prefix': 'tsun'}
+                        }
+
+@pytest.fixture
+def config_no_conn(test_port):
+    Config.act_config = {'mqtt':{'host': "", 'port': test_port, 'user': '', 'passwd': ''},
+                         'ha':{'auto_conf_prefix': 'homeassistant','discovery_prefix': 'homeassistant', 'entity_prefix': 'tsun'}
+                        }
+
+class FakeReader():
+    pass
+
+
+class FakeWriter():
+    pass
+
+
+@pytest.fixture
+def patch_open():
+    async def new_conn(conn):
+        await asyncio.sleep(0.01)
+        return FakeReader(), FakeWriter()
+    
+    def new_open(host: str, port: int):
+        return new_conn(None)
+
+    with patch.object(asyncio, 'open_connection', new_open) as conn:
+        yield conn
+
+
+@pytest.mark.asyncio
+async def test_modbus_conn(patch_open):
+    _ = patch_open
+    assert Infos.stat['proxy']['Inverter_Cnt'] == 0
+
+    async with ModbusConn('test.local', 1234) as stream:
+        assert stream.node_id == 'G3P'
+        assert stream.addr == ('test.local', 1234)
+        assert type(stream.reader) is FakeReader
+        assert type(stream.writer) is FakeWriter
+        assert Infos.stat['proxy']['Inverter_Cnt'] == 1
+    
+    assert Infos.stat['proxy']['Inverter_Cnt'] == 0
diff --git a/app/tests/test_mqtt.py b/app/tests/test_mqtt.py
index 7dea973..1d7c5dd 100644
--- a/app/tests/test_mqtt.py
+++ b/app/tests/test_mqtt.py
@@ -5,6 +5,7 @@ import aiomqtt
 import logging
 
 from mock import patch, Mock
+from app.src.singleton import Singleton
 from app.src.mqtt import Mqtt
 from app.src.modbus import Modbus
 from app.src.gen3plus.solarman_v5 import SolarmanV5
@@ -13,7 +14,10 @@ from app.src.config import Config
 
 pytest_plugins = ('pytest_asyncio',)
 
-
+@pytest.fixture(scope="module", autouse=True)
+def module_init():
+    Singleton._instances.clear()
+    yield
 
 @pytest.fixture(scope="module")
 def test_port():
diff --git a/app/tests/test_singleton.py b/app/tests/test_singleton.py
index 2ea82eb..d645e08 100644
--- a/app/tests/test_singleton.py
+++ b/app/tests/test_singleton.py
@@ -7,6 +7,7 @@ class Test(metaclass=Singleton):
         pass  # is a dummy test class
 
 def test_singleton_metaclass():
+    Singleton._instances.clear()
     a = Test()
     assert 1 == len(Singleton._instances)
     b = Test()
diff --git a/app/tests/test_solarman.py b/app/tests/test_solarman.py
index c9227bd..521ef9b 100644
--- a/app/tests/test_solarman.py
+++ b/app/tests/test_solarman.py
@@ -3,6 +3,7 @@ import struct
 import time
 import asyncio
 import logging
+import random
 from math import isclose
 from app.src.gen3plus.solarman_v5 import SolarmanV5
 from app.src.config import Config
@@ -148,6 +149,12 @@ def incorrect_checksum(buf):
     checksum = (sum(buf[1:])+1) & 0xff
     return checksum.to_bytes(length=1)
 
+@pytest.fixture(scope="session")
+def str_test_ip():
+    ip =  ".".join(str(random.randint(1, 254)) for _ in range(4))
+    print(f'random_ip: {ip}')
+    return ip
+
 @pytest.fixture
 def device_ind_msg(): # 0x4110
     msg  = b'\xa5\xd4\x00\x10\x41\x00\x01' +get_sn()  +b'\x02\xba\xd2\x00\x00'
@@ -1692,7 +1699,7 @@ async def test_modbus_polling(config_tsun_inv1, heartbeat_ind_msg, heartbeat_rsp
     m.close()
 
 @pytest.mark.asyncio
-async def test_start_client_mode(config_tsun_inv1):
+async def test_start_client_mode(config_tsun_inv1, str_test_ip):
     _ = config_tsun_inv1
     assert asyncio.get_running_loop()
     m = MemoryStream(b'')
@@ -1700,9 +1707,9 @@ async def test_start_client_mode(config_tsun_inv1):
     assert m.no_forwarding == False
     assert m.mb_timer.tim == None
     assert asyncio.get_running_loop() == m.mb_timer.loop
-    await m.send_start_cmd(get_sn_int(), '192.168.1.1', m.mb_first_timeout)
+    await m.send_start_cmd(get_sn_int(), str_test_ip, m.mb_first_timeout)
     assert m.writer.sent_pdu==bytearray(b'\xa5\x17\x00\x10E\x01\x00!Ce{\x02\xb0\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x030\x00\x000J\xde\xf1\x15')
-    assert m.db.get_db_value(Register.IP_ADDRESS) == '192.168.1.1'
+    assert m.db.get_db_value(Register.IP_ADDRESS) == str_test_ip
     assert isclose(m.db.get_db_value(Register.POLLING_INTERVAL), 0.5)
     assert m.db.get_db_value(Register.HEARTBEAT_INTERVAL) == 120
 
diff --git a/app/tests/test_talent.py b/app/tests/test_talent.py
index 62df532..13f462e 100644
--- a/app/tests/test_talent.py
+++ b/app/tests/test_talent.py
@@ -1150,7 +1150,7 @@ def test_msg_ota_invalid(config_tsun_inv1, msg_ota_invalid):
     m.close()
 
 def test_msg_unknown(config_tsun_inv1, msg_unknown):
-    config_tsun_inv1
+    _ = config_tsun_inv1
     m = MemoryStream(msg_unknown, (0,), False)
     m.db.stat['proxy']['Unknown_Msg'] = 0
     m.read()         # read complete msg, and dispatch msg
diff --git a/system_tests/test_tcp_socket.py b/system_tests/test_tcp_socket.py
index 00ec70f..e663577 100644
--- a/system_tests/test_tcp_socket.py
+++ b/system_tests/test_tcp_socket.py
@@ -13,31 +13,31 @@ def get_invalid_sn():
 
 
 @pytest.fixture
-def MsgContactInfo(): # Contact Info message
+def msg_contact_info(): # Contact Info message
     return b'\x00\x00\x00\x2c\x10'+get_sn()+b'\x91\x00\x08solarhub\x0fsolarhub\x40123456'
 
 @pytest.fixture
-def MsgContactResp(): # Contact Response message
+def msg_contact_resp(): # Contact Response message
     return b'\x00\x00\x00\x14\x10'+get_sn()+b'\x91\x00\x01'
 
 @pytest.fixture
-def MsgContactInfo2(): # Contact Info message
+def msg_contact_info2(): # Contact Info message
     return b'\x00\x00\x00\x2c\x10'+get_invalid_sn()+b'\x91\x00\x08solarhub\x0fsolarhub\x40123456'
 
 @pytest.fixture
-def MsgContactResp2(): # Contact Response message
+def msg_contact_resp2(): # Contact Response message
     return b'\x00\x00\x00\x14\x10'+get_invalid_sn()+b'\x91\x00\x01'
 
 @pytest.fixture
-def MsgTimeStampReq(): # Get Time Request message
+def msg_timestamp_req(): # Get Time Request message
     return b'\x00\x00\x00\x13\x10'+get_sn()+b'\x91\x22'           
 
 @pytest.fixture
-def MsgTimeStampResp(): # Get Time Resonse message
+def msg_timestamp_resp(): # Get Time Resonse message
     return b'\x00\x00\x00\x1b\x10'+get_sn()+b'\x99\x22\x00\x00\x01\x89\xc6\x63\x4d\x80'
 
 @pytest.fixture
-def MsgContollerInd(): # Data indication from the controller
+def msg_controller_ind(): # Data indication from the controller
     msg  =  b'\x00\x00\x01\x2f\x10'+ get_sn() + b'\x91\x71\x0e\x10\x00\x00\x10'+get_sn()
     msg +=  b'\x01\x00\x00\x01\x89\xc6\x63\x55\x50'
     msg +=  b'\x00\x00\x00\x15\x00\x09\x2b\xa8\x54\x10\x52\x53\x57\x5f\x34\x30\x30\x5f\x56\x31\x2e\x30\x30\x2e\x30\x36\x00\x09\x27\xc0\x54\x06\x52\x61\x79\x6d\x6f'
@@ -49,7 +49,7 @@ def MsgContollerInd(): # Data indication from the controller
     return msg
 
 @pytest.fixture
-def MsgInvData(): # Data indication from the controller
+def msg_inv_data(): # Data indication from the controller
     msg  =  b'\x00\x00\x00\x8b\x10'+ get_sn() + b'\x91\x04\x01\x90\x00\x01\x10'+get_inv_no()
     msg +=  b'\x01\x00\x00\x01\x89\xc6\x63\x61\x08'
     msg +=  b'\x00\x00\x00\x06\x00\x00\x00\x0a\x54\x08\x4d\x69\x63\x72\x6f\x69\x6e\x76\x00\x00\x00\x14\x54\x04\x54\x53\x55\x4e\x00\x00\x00\x1E\x54\x07\x56\x35\x2e\x30\x2e\x31\x31\x00\x00\x00\x28'
@@ -57,7 +57,7 @@ def MsgInvData(): # Data indication from the controller
     return msg
 
 @pytest.fixture
-def MsgInverterInd(): # Data indication from the inverter
+def msg_inverter_ind(): # Data indication from the inverter
     msg  = b'\x00\x00\x05\x02\x10'+ get_sn() + b'\x91\x04\x01\x90\x00\x01\x10'+get_inv_no()
     msg +=  b'\x01\x00\x00\x01\x89\xc6\x63\x61\x08'
     msg +=  b'\x00\x00\x00\xa3\x00\x00\x00\x64\x53\x00\x01\x00\x00\x00\xc8\x53\x00\x02\x00\x00\x01\x2c\x53\x00\x00\x00\x00\x01\x90\x49\x00\x00\x00\x00\x00\x00\x01\x91\x53\x00\x00'
@@ -94,7 +94,7 @@ def MsgInverterInd(): # Data indication from the inverter
     return msg
 
 @pytest.fixture
-def MsgOtaUpdateReq(): # Over the air update request from talent cloud
+def msg_ota_update_req(): # Over the air update request from talent cloud
     msg  = b'\x00\x00\x01\x16\x10'+ get_sn() + b'\x70\x13\x01\x02\x76\x35'
     msg += b'\x70\x68\x74\x74\x70'
     msg += b'\x3a\x2f\x2f\x77\x77\x77\x2e\x74\x61\x6c\x65\x6e\x74\x2d\x6d\x6f'
@@ -117,7 +117,7 @@ def MsgOtaUpdateReq(): # Over the air update request from talent cloud
 
 
 @pytest.fixture(scope="session")
-def ClientConnection():
+def client_connection():
     host = 'logger.talent-monitoring.com'
     port = 5005
     with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
@@ -127,7 +127,7 @@ def ClientConnection():
         time.sleep(2.5)
         s.close()
 
-def tempClientConnection():
+def tempclient_connection():
     host = 'logger.talent-monitoring.com'
     port = 5005
     with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
@@ -138,25 +138,25 @@ def tempClientConnection():
 
 def test_open_close():
     try:
-        for s in tempClientConnection():
-            pass
-    except:
+        for _ in tempclient_connection():
+            pass  # test side effect of generator 
+    except Exception:
         assert False
 
-def test_send_contact_info1(ClientConnection, MsgContactInfo, MsgContactResp):
-    s = ClientConnection
+def test_send_contact_info1(client_connection, msg_contact_info, msg_contact_resp):
+    s = client_connection
     try:
-        s.sendall(MsgContactInfo)
+        s.sendall(msg_contact_info)
         data = s.recv(1024)
     except TimeoutError:
         pass
-    assert data == MsgContactResp
+    assert data == msg_contact_resp
 
 
-def test_send_contact_info2(ClientConnection, MsgContactInfo2, MsgContactInfo, MsgContactResp):
-    s = ClientConnection  
+def test_send_contact_info2(client_connection, msg_contact_info2, msg_contact_info, msg_contact_resp):
+    s = client_connection  
     try:
-        s.sendall(MsgContactInfo2)
+        s.sendall(msg_contact_info2)
         data = s.recv(1024)
     except TimeoutError:
         pass
@@ -164,73 +164,73 @@ def test_send_contact_info2(ClientConnection, MsgContactInfo2, MsgContactInfo, M
         assert False
 
     try:
-        s.sendall(MsgContactInfo)
+        s.sendall(msg_contact_info)
         data = s.recv(1024)
     except TimeoutError:
         pass
-    assert data == MsgContactResp
+    assert data == msg_contact_resp
 
-def test_send_contact_info3(ClientConnection, MsgContactInfo, MsgContactResp, MsgTimeStampReq):
-    s = ClientConnection
+def test_send_contact_info3(client_connection, msg_contact_info, msg_contact_resp, msg_timestamp_req):
+    s = client_connection
     try:
-        s.sendall(MsgContactInfo)
+        s.sendall(msg_contact_info)
         data = s.recv(1024)
     except TimeoutError:
         pass
-    assert data == MsgContactResp
+    assert data == msg_contact_resp
     try:
-        s.sendall(MsgTimeStampReq)
+        s.sendall(msg_timestamp_req)
         data = s.recv(1024)
     except TimeoutError:
         pass
  
 
-def test_send_contact_resp(ClientConnection, MsgContactResp):
-    s = ClientConnection  
+def test_send_contact_resp(client_connection, msg_contact_resp):
+    s = client_connection  
     try:
-        s.sendall(MsgContactResp)
+        s.sendall(msg_contact_resp)
         data = s.recv(1024)
     except TimeoutError:
         pass
     else:
         assert data == b''
 
-def test_send_ctrl_data(ClientConnection, MsgTimeStampReq, MsgTimeStampResp, MsgContollerInd):
-    s = ClientConnection  
+def test_send_ctrl_data(client_connection, msg_timestamp_req, msg_timestamp_resp, msg_controller_ind):
+    s = client_connection  
     try:
-        s.sendall(MsgTimeStampReq)
-        data = s.recv(1024)
+        s.sendall(msg_timestamp_req)
+        _ = s.recv(1024)
     except TimeoutError:
         pass
   #  time.sleep(2.5)
-  #  assert data == MsgTimeStampResp
+  #  assert data == msg_timestamp_resp
     try:
-        s.sendall(MsgContollerInd)
-        data = s.recv(1024)
+        s.sendall(msg_controller_ind)
+        _ = s.recv(1024)
     except TimeoutError:
         pass
 
-def test_send_inv_data(ClientConnection, MsgTimeStampReq, MsgTimeStampResp, MsgInvData, MsgInverterInd):
-    s = ClientConnection  
+def test_send_inv_data(client_connection, msg_timestamp_req, msg_timestamp_resp, msg_inv_data, msg_inverter_ind):
+    s = client_connection  
     try:
-        s.sendall(MsgTimeStampReq)
-        data = s.recv(1024)
+        s.sendall(msg_timestamp_req)
+        _ = s.recv(1024)
     except TimeoutError:
         pass
   #  time.sleep(32.5)
-  #  assert data == MsgTimeStampResp
+  #  assert data == msg_timestamp_resp
     try:
-        s.sendall(MsgInvData)
-        data = s.recv(1024)
-        s.sendall(MsgInverterInd)
-        data = s.recv(1024)
+        s.sendall(msg_inv_data)
+        _ = s.recv(1024)
+        s.sendall(msg_inverter_ind)
+        _ = s.recv(1024)
     except TimeoutError:
         pass
 
-def test_ota_req(ClientConnection, MsgOtaUpdateReq):
-    s = ClientConnection  
+def test_ota_req(client_connection, msg_ota_update_req):
+    s = client_connection  
     try:
-        s.sendall(MsgOtaUpdateReq)
-        data = s.recv(1024)
+        s.sendall(msg_ota_update_req)
+        _ = s.recv(1024)
     except TimeoutError:
         pass