More coverage improvements (#711)

* More coverage improvements

* Drop redundant 'sleep' usage in test utils

httpx/backends/auto.py

@@ -18,7 +18,7 @@ class AutoBackend(ConcurrencyBackend):
     def backend(self) -> ConcurrencyBackend:
         if not hasattr(self, "_backend_implementation"):
             backend = sniffio.current_async_library()
-            if backend not in ("asyncio", "trio"):
+            if backend not in ("asyncio", "trio"):  # pragma: nocover
                 raise RuntimeError(f"Unsupported concurrency backend {backend!r}")
             self._backend_implementation = lookup_backend(backend)
         return self._backend_implementation

httpx/utils.py

@@ -253,15 +253,6 @@ def get_logger(name: str) -> Logger:
     return typing.cast(Logger, logger)
 
 
-def kv_format(**kwargs: typing.Any) -> str:
-    """Format arguments into a key=value line.
-
-    >>> formatkv(x=1, name="Bob")
-    "x=1 name='Bob'"
-    """
-    return " ".join(f"{key}={value!r}" for key, value in kwargs.items())
-
-
 def should_not_be_proxied(url: "URL") -> bool:
     """ Return True if url should not be proxied,
     return False otherwise.

tests/concurrency.py

@@ -14,26 +14,6 @@ from httpx.backends.auto import AutoBackend
 from httpx.backends.trio import TrioBackend
 
 
-@functools.singledispatch
-async def sleep(backend, seconds: int):
-    raise NotImplementedError  # pragma: no cover
-
-
-@sleep.register(AutoBackend)
-async def _sleep_auto(backend, seconds: int):
-    return await sleep(backend.backend, seconds=seconds)
-
-
-@sleep.register(AsyncioBackend)
-async def _sleep_asyncio(backend, seconds: int):
-    await asyncio.sleep(seconds)
-
-
-@sleep.register(TrioBackend)
-async def _sleep_trio(backend, seconds: int):
-    await trio.sleep(seconds)
-
-
 @functools.singledispatch
 async def run_concurrently(backend, *coroutines: typing.Callable[[], typing.Awaitable]):
     raise NotImplementedError  # pragma: no cover

tests/dispatch/utils.py

@@ -7,7 +7,6 @@ import h2.events
 
 from httpx import Request, Timeout
 from httpx.backends.base import BaseSocketStream, lookup_backend
-from tests.concurrency import sleep
 
 
 class MockHTTP2Backend:
@@ -49,7 +48,6 @@ class MockHTTP2Server(BaseSocketStream):
         return "HTTP/2"
 
     async def read(self, n, timeout, flag=None) -> bytes:
-        await sleep(self.backend, 0)
         send, self.buffer = self.buffer[:n], self.buffer[n:]
         return send
 
@@ -195,7 +193,6 @@ class MockRawSocketStream(BaseSocketStream):
         self.backend.received_data.append(data)
 
     async def read(self, n, timeout, flag=None) -> bytes:
-        await sleep(self.backend.backend, 0)
         if not self.backend.data_to_send:
             return b""
         return self.backend.data_to_send.pop(0)

tests/test_decoders.py

@@ -125,10 +125,7 @@ def test_decoding_errors(header_value):
     body = b"test 123"
     compressed_body = brotli.compress(body)[3:]
     with pytest.raises(httpx.DecodingError):
-        response = httpx.Response(
-            200, headers=headers, content=compressed_body, request=REQUEST
-        )
-        response.content
+        httpx.Response(200, headers=headers, content=compressed_body, request=REQUEST)
 
 
 @pytest.mark.parametrize(