Add user_agent interceptor test

Author: alextwoods

packages/smithy-http/src/smithy_http/interceptors/user_agent.py

@@ -17,7 +17,7 @@ class UserAgentInterceptor(Interceptor[Any, None, HTTPRequest, None]):
     def read_before_execution(
         self, context: InterceptorContext[Any, None, None, None]
     ) -> None:
-        context.properties["user_agent"] = _UserAgentBuilder.from_environment().build()
+        context.properties["user_agent"] = UserAgentBuilder.from_environment().build()
 
     def modify_before_signing(
         self, context: InterceptorContext[Any, None, HTTPRequest, None]
@@ -42,24 +42,23 @@ def modify_before_signing(
 _USERAGENT_SDK_NAME = "python"
 
 
-class _UserAgentBuilder:
+class UserAgentBuilder:
     def __init__(
         self,
         *,
-        platform_name: str | None,
-        platform_version: str | None,
-        platform_machine: str | None,
-        python_version: str | None,
-        python_implementation: str | None,
+        platform_name: str | None = None,
+        platform_version: str | None = None,
+        platform_machine: str | None = None,
+        python_version: str | None = None,
+        python_implementation: str | None = None,
         sdk_version: str | None = None,
     ) -> None:
         self._platform_name = platform_name
         self._platform_version = platform_version
         self._platform_machine = platform_machine
         self._python_version = python_version
         self._python_implementation = python_implementation
-        # TODO: Allow configuration through context
-        self._sdk_version = smithy_core.__version__
+        self._sdk_version = sdk_version
 
     @classmethod
     def from_environment(cls) -> Self:
@@ -69,20 +68,26 @@ def from_environment(cls) -> Self:
             platform_machine=platform.machine(),
             python_version=platform.python_version(),
             python_implementation=platform.python_implementation(),
+            sdk_version=smithy_core.__version__,
         )
 
     def build(self) -> UserAgent:
         user_agent = UserAgent()
-        user_agent.sdk_metadata.append(
-            UserAgentComponent(prefix=_USERAGENT_SDK_NAME, name=self._sdk_version)
-        )
+        user_agent.sdk_metadata.extend(self._build_sdk_metadata())
         user_agent.ua_metadata.append(UserAgentComponent(prefix="ua", name="2.1"))
         user_agent.os_metadata.extend(self._build_os_metadata())
         user_agent.os_metadata.extend(self._build_architecture_metadata())
         user_agent.language_metadata.extend(self._build_language_metadata())
 
         return user_agent
 
+    def _build_sdk_metadata(self) -> list[UserAgentComponent]:
+        if self._sdk_version:
+            return [
+                UserAgentComponent(prefix=_USERAGENT_SDK_NAME, name=self._sdk_version)
+            ]
+        return []
+
     def _build_os_metadata(self) -> list[UserAgentComponent]:
         """Build the OS/platform components of the User-Agent header string.
 
@@ -97,7 +102,7 @@ def _build_os_metadata(self) -> list[UserAgentComponent]:
          * ``os/other``
          * ``os/other md/foobar#1.2.3``
         """
-        if self._platform_name is None:
+        if self._platform_name is None or self._platform_name == "":
             return [UserAgentComponent("os", "other")]
 
         plt_name_lower = self._platform_name.lower()

packages/smithy-http/tests/unit/interceptors/test_user_agent.py

@@ -0,0 +1,71 @@
+import platform
+
+import smithy_core
+from smithy_http.interceptors.user_agent import UserAgentBuilder
+
+
+def test_from_environment(monkeypatch):  # type: ignore
+    monkeypatch.setattr(platform, "system", lambda: "Linux")  # type: ignore
+    monkeypatch.setattr(platform, "release", lambda: "5.4.228-131.415.AMZN2.X86_64")  # type: ignore
+    monkeypatch.setattr(platform, "python_version", lambda: "4.3.2")  # type: ignore
+    monkeypatch.setattr(platform, "python_implementation", lambda: "Cpython")  # type: ignore
+    monkeypatch.setattr(smithy_core, "__version__", "1.2.3")  # type: ignore
+
+    user_agent = str(UserAgentBuilder.from_environment().build())
+    assert "python/1.2.3" in user_agent
+    assert "os/linux#5.4.228-131.415.AMZN2.X86_64" in user_agent
+    assert "md/arch#arm64" in user_agent
+    assert "lang/python#4.3.2" in user_agent
+    assert "md/pyimpl#Cpython" in user_agent
+
+
+def test_build_adds_sdk_metadata():
+    user_agent = UserAgentBuilder(sdk_version="1.2.3").build()
+    assert "python/1.2.3" in str(user_agent)
+
+
+def test_build_adds_ua_metadata():
+    user_agent = UserAgentBuilder().build()
+    assert "ua/2.1" in str(user_agent)
+
+
+def test_build_os_defaults_to_other():
+    user_agent = UserAgentBuilder().build()
+    assert "os/other" in str(user_agent)
+
+
+def test_build_os_lowercases_platform():
+    user_agent = UserAgentBuilder(platform_name="LINUX").build()
+    assert "os/linux" in str(user_agent)
+
+
+def test_build_os_maps_platform_names():
+    user_agent = UserAgentBuilder(platform_name="darwin").build()
+    assert "os/macos" in str(user_agent)
+
+
+def test_build_os_includes_version():
+    user_agent = UserAgentBuilder(platform_name="linux", platform_version="5.4").build()
+    assert "os/linux#5.4" in str(user_agent)
+
+
+def test_build_os_other_platform():
+    user_agent = UserAgentBuilder(
+        platform_name="myos", platform_version="0.0.1"
+    ).build()
+    assert "os/other md/myos#0.0.1" in str(user_agent)
+
+
+def test_build_arch_adds_md():
+    user_agent = UserAgentBuilder(platform_machine="x86_64").build()
+    assert "md/arch#x86_64" in str(user_agent)
+
+
+def test_build_language_version():
+    user_agent = UserAgentBuilder(python_version="3.12").build()
+    assert "lang/python#3.12" in str(user_agent)
+
+
+def test_build_language_implementation():
+    user_agent = UserAgentBuilder(python_implementation="CPython").build()
+    assert "md/pyimpl#CPython" in str(user_agent)