Reduce number of Optional return values (#217)

* Disallow slice assigning routes

* type CallList

* Remove unnececary backend arg

* type side_effect setter

* configure mypy - include tests for mypy

* Test python 3.11

* Make Call.response non optional, raise instead

* assert resolved.response is not None

* type ignore bad usage

* use == instead of is to be reachable

* Introduce Noop to make pattern non optional

* Add Call.has_response helper

Author: lundberg

noxfile.py

@@ -9,7 +9,7 @@
 docs_requirements = ("mkdocs", "mkdocs-material", "mkautodoc>=0.1.0")
 
 
-@nox.session(python=["3.6", "3.7", "3.8", "3.9", "3.10"])
+@nox.session(python=["3.6", "3.7", "3.8", "3.9", "3.10", "3.11"])
 def test(session):
     deps = ["pytest", "pytest-asyncio", "pytest-cov", "trio", "starlette", "flask"]
     session.install("--upgrade", *deps)
@@ -30,7 +30,7 @@ def check(session):
     session.run("black", "--check", "--diff", "--target-version=py36", *source_files)
     session.run("isort", "--check", "--diff", "--project=respx", *source_files)
     session.run("flake8", *source_files)
-    session.run("mypy", "respx")
+    session.run("mypy")
 
 
 @nox.session

respx/models.py

@@ -44,30 +44,40 @@ def clone_response(response: httpx.Response, request: httpx.Request) -> httpx.Re
 
 class Call(NamedTuple):
     request: httpx.Request
-    response: Optional[httpx.Response]
+    optional_response: Optional[httpx.Response]
+
+    @property
+    def response(self) -> httpx.Response:
+        if self.optional_response is None:
+            raise ValueError(f"{self!r} has no response")
+        return self.optional_response
+
+    @property
+    def has_response(self) -> bool:
+        return self.optional_response is not None
 
 
 class CallList(list, mock.NonCallableMock):
-    def __init__(self, *args, name="respx", **kwargs):
-        super().__init__(*args, **kwargs)
+    def __init__(self, *args: Sequence[Call], name: Any = "respx") -> None:
+        super().__init__(*args)
         mock.NonCallableMock.__init__(self, name=name)
 
     @property
-    def called(self) -> bool:  # type: ignore
+    def called(self) -> bool:  # type: ignore[override]
         return bool(self)
 
     @property
-    def call_count(self) -> int:  # type: ignore
+    def call_count(self) -> int:  # type: ignore[override]
         return len(self)
 
     @property
-    def last(self) -> Optional[Call]:
-        return self[-1] if self else None
+    def last(self) -> Call:
+        return self[-1]
 
     def record(
         self, request: httpx.Request, response: Optional[httpx.Response]
     ) -> Call:
-        call = Call(request=request, response=response)
+        call = Call(request=request, optional_response=response)
         self.append(call)
         return call
 
@@ -155,7 +165,7 @@ def name(self, name: str) -> None:
         raise NotImplementedError("Can't set name on route.")
 
     @property
-    def pattern(self) -> Optional[Pattern]:
+    def pattern(self) -> Pattern:
         return self._pattern
 
     @pattern.setter
@@ -174,7 +184,9 @@ def return_value(self, return_value: Optional[httpx.Response]) -> None:
         self._return_value = return_value
 
     @property
-    def side_effect(self) -> Optional[SideEffectTypes]:
+    def side_effect(
+        self,
+    ) -> Optional[Union[SideEffectTypes, Sequence[SideEffectListTypes]]]:
         return self._side_effect
 
     @side_effect.setter
@@ -230,7 +242,9 @@ def mock(
         self,
         return_value: Optional[httpx.Response] = None,
         *,
-        side_effect: Optional[SideEffectTypes] = None,
+        side_effect: Optional[
+            Union[SideEffectTypes, Sequence[SideEffectListTypes]]
+        ] = None,
     ) -> "Route":
         self.return_value = return_value
         self.side_effect = side_effect
@@ -430,6 +444,8 @@ def __setitem__(self, i: slice, routes: "RouteList") -> None:
         """
         Re-set all routes to given routes.
         """
+        if (i.start, i.stop, i.step) != (None, None, None):
+            raise TypeError("Can't slice assign routes")
         self._routes = list(routes._routes)
         self._names = dict(routes._names)
 

respx/patterns.py

@@ -88,13 +88,26 @@ def __init__(self, value: Any, lookup: Optional[Lookup] = None) -> None:
     def __iter__(self):
         yield self
 
+    def __bool__(self):
+        return True
+
     def __and__(self, other: "Pattern") -> "Pattern":
+        if not bool(other):
+            return self
+        elif not bool(self):
+            return other
         return _And((self, other))
 
     def __or__(self, other: "Pattern") -> "Pattern":
+        if not bool(other):
+            return self
+        elif not bool(self):
+            return other
         return _Or((self, other))
 
     def __invert__(self):
+        if not bool(self):
+            return self
         return _Invert(self)
 
     def __repr__(self):  # pragma: nocover
@@ -159,6 +172,22 @@ def _in(self, value: Any) -> Match:
         return Match(value in self.value)
 
 
+class Noop(Pattern):
+    def __init__(self) -> None:
+        super().__init__(None)
+
+    def __repr__(self):
+        return f"<{self.__class__.__name__}>"
+
+    def __bool__(self) -> bool:
+        # Treat this pattern as non-existent, e.g. when filtering or conditioning
+        return False
+
+    def match(self, request: httpx.Request) -> Match:
+        # If this pattern is part of a combined pattern, always be truthy, i.e. noop
+        return Match(True)
+
+
 class PathPattern(Pattern):
     path: Optional[str]
 
@@ -500,7 +529,7 @@ def clean(self, value: Dict) -> bytes:
         return data
 
 
-def M(*patterns: Pattern, **lookups: Any) -> Optional[Pattern]:
+def M(*patterns: Pattern, **lookups: Any) -> Pattern:
     extras = None
 
     for pattern__lookup, value in lookups.items():
@@ -550,12 +579,10 @@ def get_scheme_port(scheme: Optional[str]) -> Optional[int]:
     return {"http": 80, "https": 443}.get(scheme or "")
 
 
-def combine(
-    patterns: Sequence[Pattern], op: Callable = operator.and_
-) -> Optional[Pattern]:
+def combine(patterns: Sequence[Pattern], op: Callable = operator.and_) -> Pattern:
     patterns = tuple(filter(None, patterns))
     if not patterns:
-        return None
+        return Noop()
     return reduce(op, patterns)
 
 
@@ -598,14 +625,14 @@ def parse_url_patterns(
     return bases
 
 
-def merge_patterns(pattern: Optional[Pattern], **bases: Pattern) -> Optional[Pattern]:
+def merge_patterns(pattern: Pattern, **bases: Pattern) -> Pattern:
     if not bases:
         return pattern
 
-    if pattern:
-        # Flatten pattern
-        patterns = list(iter(pattern))
+    # Flatten pattern
+    patterns: List[Pattern] = list(filter(None, iter(pattern)))
 
+    if patterns:
         if "host" in (_pattern.key for _pattern in patterns):
             # Pattern is "absolute", skip merging
             bases = {}

setup.cfg

@@ -36,6 +36,10 @@ skip_covered = True
 show_missing = True
 
 [mypy]
+python_version = 3.6
+files = respx,tests
+pretty = True
+
 no_implicit_reexport = True
 no_implicit_optional = True
 strict_equality = True
@@ -53,3 +57,12 @@ show_error_codes = True
 
 [mypy-pytest.*]
 ignore_missing_imports = True
+
+[mypy-trio.*]
+ignore_missing_imports = True
+
+[mypy-flask.*]
+ignore_missing_imports = True
+
+[mypy-starlette.*]
+ignore_missing_imports = True

tests/test_api.py

@@ -99,7 +99,7 @@ async def test_url_match(client, url, pattern):
 async def test_invalid_url_pattern():
     async with MockRouter() as respx_mock:
         with pytest.raises(TypeError):
-            respx_mock.get(["invalid"])
+            respx_mock.get(["invalid"])  # type: ignore[arg-type]
 
 
 @pytest.mark.asyncio
@@ -277,7 +277,10 @@ async def test_raising_content(client):
     async with MockRouter() as respx_mock:
         url = "https://foo.bar/"
         request = respx_mock.get(url)
-        request.side_effect = httpx.ConnectTimeout("X-P", request=None)
+        request.side_effect = httpx.ConnectTimeout(
+            "X-P",
+            request=None,  # type: ignore[arg-type]
+        )
         with pytest.raises(httpx.ConnectTimeout):
             await client.get(url)
 
@@ -293,7 +296,9 @@ async def test_raising_content(client):
 
         assert route.call_count == 2
         assert route.calls.last.request is not None
-        assert route.calls.last.response is None
+        assert route.calls.last.has_response is False
+        with pytest.raises(ValueError, match="has no response"):
+            assert route.calls.last.response
 
 
 @pytest.mark.asyncio
@@ -356,7 +361,9 @@ def callback(request, name):
         assert response.text == "hello lundberg"
 
         with pytest.raises(TypeError):
-            respx_mock.get("https://ham.spam/").mock(side_effect=lambda req: "invalid")
+            respx_mock.get("https://ham.spam/").mock(
+                side_effect=lambda req: "invalid"  # type: ignore[arg-type,return-value]
+            )
             await client.get("https://ham.spam/")
 
         with pytest.raises(httpx.NetworkError):
@@ -526,10 +533,10 @@ def test_add():
         assert respx.routes["foobar"].called
 
         with pytest.raises(TypeError):
-            respx.add(route, status_code=418)  # pragma: nocover
+            respx.add(route, status_code=418)  # type: ignore[call-arg]
 
         with pytest.raises(ValueError):
-            respx.add("GET")  # pragma: nocover
+            respx.add("GET")  # type: ignore[arg-type]
 
         with pytest.raises(NotImplementedError):
             route.name = "spam"
@@ -554,7 +561,7 @@ def test_respond():
             route.respond(content={})
 
         with pytest.raises(TypeError, match="content can only be"):
-            route.respond(content=Exception())
+            route.respond(content=Exception())  # type: ignore[arg-type]
 
 
 @pytest.mark.asyncio

tests/test_mock.py

@@ -317,25 +317,25 @@ async def test_configured_router_reuse(client):
     with router:
         route.return_value = httpx.Response(202)
         response = await client.get("https://foo/bar/")
-        assert route.called is True
+        assert route.called == True  # noqa: E712
         assert response.status_code == 202
         assert router.calls.call_count == 1
         assert respx.calls.call_count == 0
 
     assert len(router.routes) == 1
-    assert route.called is False
+    assert route.called == False  # noqa: E712
     assert router.calls.call_count == 0
 
     async with router:
         assert router.calls.call_count == 0
         response = await client.get("https://foo/bar/")
-        assert route.called is True
+        assert route.called == True  # noqa: E712
         assert response.status_code == 404
         assert router.calls.call_count == 1
         assert respx.calls.call_count == 0
 
     assert len(router.routes) == 1
-    assert route.called is False
+    assert route.called == False  # noqa: E712
     assert router.calls.call_count == 0
     assert respx.calls.call_count == 0
 
@@ -346,7 +346,7 @@ async def test_router_return_type_misuse():
     route = router.get("https://hot.dog/")
 
     with pytest.raises(TypeError):
-        route.return_value = "not-a-httpx-response"
+        route.return_value = "not-a-httpx-response"  # type: ignore[assignment]
 
 
 @pytest.mark.asyncio
@@ -396,20 +396,20 @@ async def test_start_stop(client):
     try:
         respx.start()
         response = await client.get(url)
-        assert request.called is True
+        assert request.called == True  # noqa: E712
         assert response.status_code == 202
         assert response.text == ""
         assert respx.calls.call_count == 1
 
         respx.stop(clear=False, reset=False)
         assert len(respx.routes) == 1
         assert respx.calls.call_count == 1
-        assert request.called is True
+        assert request.called == True  # noqa: E712
 
         respx.reset()
         assert len(respx.routes) == 1
         assert respx.calls.call_count == 0
-        assert request.called is False
+        assert request.called == False  # noqa: E712
 
         respx.clear()
         assert len(respx.routes) == 0
@@ -545,7 +545,7 @@ async def test():
 
 def test_router_using__invalid():
     with pytest.raises(ValueError, match="using"):
-        respx.MockRouter(using=123).using
+        respx.MockRouter(using=123).using  # type: ignore[arg-type]
 
 
 def test_mocker_subclass():

tests/test_patterns.py

@@ -15,6 +15,7 @@
     Lookup,
     M,
     Method,
+    Noop,
     Params,
     Path,
     Pattern,
@@ -66,6 +67,18 @@ def test_match_context():
     assert match.context == {"host": "foo.bar", "slug": "baz"}
 
 
+def test_noop_pattern():
+    assert bool(Noop()) is False
+    assert bool(Noop().match(httpx.Request("GET", "https://example.org"))) is True
+    assert list(filter(None, [Noop()])) == []
+    assert repr(Noop()) == "<Noop>"
+    assert isinstance(~Noop(), Noop)
+    assert Method("GET") & Noop() == Method("GET")
+    assert Noop() & Method("GET") == Method("GET")
+    assert Method("GET") | Noop() == Method("GET")
+    assert Noop() | Method("GET") == Method("GET")
+
+
 @pytest.mark.parametrize(
     "kwargs,url,expected",
     [

tests/test_remote.py

@@ -37,7 +37,7 @@ def test_remote_pass_through(using, client_lib, call_count):  # pragma: nocover
         assert response.json()["json"] == {"foo": "bar"}
 
         assert respx_mock.calls.last.request.url == url
-        assert respx_mock.calls.last.response is None
+        assert respx_mock.calls.last.has_response is False
 
         assert route.call_count == call_count
         assert respx_mock.calls.call_count == call_count