Add unit tests

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "bmspy"
-version = "2.0"
+version = "2.1"
 description = "bmspy is a tool to get information from a xiaoxiang-type BMS system"
 authors = ["Timothy Allen <tim@treehouse.org.za>"]
 license = "CC BY-NC-SA 4.0"
@@ -8,19 +8,29 @@ readme = "README.md"
 
 [tool.poetry.dependencies]
 python = ">=3.12,<4.0"
-pyserial = "^3.5"
-influxdb3-python = {version = "^0.19.0", optional = true, extras = ["influxdb"]}
+pyserial = ">=3.5"
+influxdb3-python = {version = ">=0.19.0", optional = true, extras = ["influxdb"]}
 typing-extensions = {version = ">=4.13", optional = true, extras = ["influxdb"]}
-prometheus-client = {version = "^0.11.0", optional = true, extras = ["prometheus"]}
+prometheus-client = {version = ">=0.11.0", optional = true, extras = ["prometheus"]}
 
 [tool.poetry.extras]
 influxdb = ["influxdb3-python", "typing-extensions"]
 prometheus = ["prometheus-client"]
 
+[tool.poetry.group.dev.dependencies]
+pytest = ">=8.0"
+pytest-cov = ">=7.1.0"
+
 [build-system]
 requires = ["poetry-core"]
 build-backend = "poetry.core.masonry.api"
 
+[tool.coverage.report]
+exclude_lines = [
+    "pragma: no cover",
+    "if __name__ == .__main__.:",
+]
+
 [tool.poetry.scripts]
 bmspy = "bmspy:main"
 bmspy-server = "bmspy.server:main"