Add scalar.proto, generate stubs, implement converter, and add unit tests.

pyproject.toml

@@ -13,8 +13,7 @@ protobuf = {version=">=4.21"}
 ni-measurement-plugin-sdk = {version=">=2.3"}
 typing-extensions = ">=4.13.2"
 streamlit = ">=1.24"
-# Temporary dependency until ni-apis-python is available.
-nitypes = ">=0.1.0dev1"
+nitypes = {version=">=0.1.0dev1", allow-prereleases=true}
 
 [tool.poetry.group.dev.dependencies]
 types-grpcio = ">=1.0"

src/nipanel/converters/protobuf_types.py

@@ -1,14 +1,23 @@
 """Classes to convert between measurement specific protobuf types and containers."""
 
-from typing import Any, Type
+from typing import Type, Union
 
 from ni.protobuf.types import scalar_pb2
 from nitypes.scalar import Scalar
+from typing_extensions import TypeAlias
 
 from nipanel.converters import Converter
 
+_AnyScalarType: TypeAlias = Union[bool, int, float, str]
+SCALAR_TYPE_TO_PB_ATTR_MAP = {
+    bool: "bool_value",
+    int: "int32_value",
+    float: "double_value",
+    str: "string_value",
+}
 
-class ScalarConverter(Converter[Scalar[Any], scalar_pb2.ScalarData]):
+
+class ScalarConverter(Converter[Scalar[_AnyScalarType], scalar_pb2.ScalarData]):
     """A converter for Scalar objects."""
 
     @property
@@ -21,36 +30,26 @@ def protobuf_message(self) -> Type[scalar_pb2.ScalarData]:
         """The type-specific protobuf message for the Python type."""
         return scalar_pb2.ScalarData
 
-    def to_protobuf_message(self, python_value: Scalar[Any]) -> scalar_pb2.ScalarData:
+    def to_protobuf_message(self, python_value: Scalar[_AnyScalarType]) -> scalar_pb2.ScalarData:
         """Convert the Python Scalar to a protobuf scalar_pb2.ScalarData."""
         message = self.protobuf_message()
         message.units = python_value.units
-        if isinstance(python_value.value, bool):
-            message.bool_value = python_value.value
-        elif isinstance(python_value.value, int):
-            message.int32_value = python_value.value
-        elif isinstance(python_value.value, float):
-            message.double_value = python_value.value
-        elif isinstance(python_value.value, str):
-            message.string_value = python_value.value
-        else:
+
+        value_attr = SCALAR_TYPE_TO_PB_ATTR_MAP.get(type(python_value.value), None)
+        if not value_attr:
             raise TypeError(f"Unexpected type for python_value.value: {type(python_value.value)}")
+        setattr(message, value_attr, python_value.value)
 
         return message
 
-    def to_python_value(self, protobuf_value: scalar_pb2.ScalarData) -> Scalar[Any]:
+    def to_python_value(self, protobuf_value: scalar_pb2.ScalarData) -> Scalar[_AnyScalarType]:
         """Convert the protobuf message to a Python Scalar."""
         if protobuf_value.units is None:
             raise ValueError("protobuf.units cannot be None.")
 
-        pb_type = protobuf_value.WhichOneof("value")
-        if pb_type == "bool_value":
-            return Scalar(protobuf_value.bool_value, protobuf_value.units)
-        elif pb_type == "int32_value":
-            return Scalar(protobuf_value.int32_value, protobuf_value.units)
-        elif pb_type == "double_value":
-            return Scalar(protobuf_value.double_value, protobuf_value.units)
-        elif pb_type == "string_value":
-            return Scalar(protobuf_value.string_value, protobuf_value.units)
-        else:
+        pb_type = str(protobuf_value.WhichOneof("value"))
+        if pb_type not in SCALAR_TYPE_TO_PB_ATTR_MAP.values():
             raise ValueError(f"Unexpected value for protobuf_value.WhichOneOf: {pb_type}")
+
+        value = getattr(protobuf_value, pb_type)
+        return Scalar(value, protobuf_value.units)

tests/unit/test_protobuf_type_conversion.py

@@ -74,7 +74,6 @@ def test___scalar_protobuf_value_unset___convert___throws_type_error() -> None:
 def test___scalar_protobuf_units_unset___convert___python_units_blank() -> None:
     protobuf_value = ScalarData()
     protobuf_value.bool_value = True
-    print(f"Protobuf units: {protobuf_value.units!r}")
 
     converter = ScalarConverter()
     python_value = converter.to_python_value(protobuf_value)