test(stream): mark unreachable stream-body lines no-cover

The new bounded-error-body tests raise on stream enter, so the `async with`
body never runs. Match the file's existing idiom (pytest.fail(...) #
pragma: no cover) to restore 100% line coverage.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: lesnik512

tests/test_client_stream.py

@@ -351,7 +351,7 @@ def handler(request: httpx2.Request) -> httpx2.Response:  # noqa: ARG001
     )
     with pytest.raises(ResponseTooLargeError) as caught:
         async with client.stream("GET", "https://example.test/x"):
-            pass
+            pytest.fail("unreachable")  # pragma: no cover
     assert caught.value.limit == 10  # noqa: PLR2004 — mirrors max_error_body_bytes above
     assert caught.value.content_length == 200  # noqa: PLR2004 — len(body) above
     await client.aclose()
@@ -368,7 +368,7 @@ def handler(request: httpx2.Request) -> httpx2.Response:  # noqa: ARG001
     )
     with pytest.raises(NotFoundError) as caught:
         async with client.stream("GET", "https://example.test/x"):
-            pass
+            pytest.fail("unreachable")  # pragma: no cover
     assert caught.value.response.content == body
     await client.aclose()
 
@@ -382,7 +382,7 @@ def handler(request: httpx2.Request) -> httpx2.Response:  # noqa: ARG001
     client = AsyncClient(httpx2_client=httpx2.AsyncClient(transport=httpx2.MockTransport(handler)))
     with pytest.raises(InternalServerError) as caught:
         async with client.stream("GET", "https://example.test/x"):
-            pass
+            pytest.fail("unreachable")  # pragma: no cover
     assert caught.value.response.content == body
     await client.aclose()
 

tests/test_client_stream_sync.py

@@ -316,7 +316,7 @@ def handler(request: httpx2.Request) -> httpx2.Response:  # noqa: ARG001
 
     client = Client(httpx2_client=httpx2.Client(transport=httpx2.MockTransport(handler)), max_error_body_bytes=10)
     with pytest.raises(ResponseTooLargeError) as caught, client.stream("GET", "https://example.test/x"):
-        pass
+        pytest.fail("unreachable")  # pragma: no cover
     assert caught.value.limit == 10  # noqa: PLR2004 — mirrors max_error_body_bytes above
     assert caught.value.content_length == 200  # noqa: PLR2004 — len(body) above
     client.close()
@@ -330,7 +330,7 @@ def handler(request: httpx2.Request) -> httpx2.Response:  # noqa: ARG001
 
     client = Client(httpx2_client=httpx2.Client(transport=httpx2.MockTransport(handler)), max_error_body_bytes=1000)
     with pytest.raises(NotFoundError) as caught, client.stream("GET", "https://example.test/x"):
-        pass
+        pytest.fail("unreachable")  # pragma: no cover
     assert caught.value.response.content == body
     client.close()
 
@@ -343,6 +343,6 @@ def handler(request: httpx2.Request) -> httpx2.Response:  # noqa: ARG001
 
     client = Client(httpx2_client=httpx2.Client(transport=httpx2.MockTransport(handler)))
     with pytest.raises(InternalServerError) as caught, client.stream("GET", "https://example.test/x"):
-        pass
+        pytest.fail("unreachable")  # pragma: no cover
     assert caught.value.response.content == body
     client.close()