Keep patterns with empty value and equal lookup (#206)

Author: lundberg

respx/patterns.py

@@ -504,9 +504,6 @@ def M(*patterns: Pattern, **lookups: Any) -> Optional[Pattern]:
     extras = None
 
     for pattern__lookup, value in lookups.items():
-        if not value:
-            continue
-
         # Handle url pattern
         if pattern__lookup == "url":
             extras = parse_url_patterns(value)
@@ -535,6 +532,10 @@ def M(*patterns: Pattern, **lookups: Any) -> Optional[Pattern]:
             lookup = Lookup(lookup_name) if lookup_name else None
             pattern = P(value, lookup=lookup)
 
+        # Skip patterns with no value, exept when using equal lookup
+        if not pattern.value and pattern.lookup is not Lookup.EQUAL:
+            continue
+
         patterns += (pattern,)
 
     # Combine and merge patterns

tests/test_patterns.py

@@ -66,6 +66,19 @@ def test_match_context():
     assert match.context == {"host": "foo.bar", "slug": "baz"}
 
 
+@pytest.mark.parametrize(
+    "kwargs,url,expected",
+    [
+        ({"params__eq": {}}, "https://foo.bar/", True),
+        ({"params__eq": {}}, "https://foo.bar/?x=y", False),
+        ({"params__contains": {}}, "https://foo.bar/?x=y", True),
+    ],
+)
+def test_m_pattern(kwargs, url, expected):
+    request = httpx.Request("GET", url)
+    assert bool(M(host="foo.bar", **kwargs).match(request)) is expected
+
+
 @pytest.mark.parametrize(
     "lookup,value,expected",
     [
@@ -217,6 +230,8 @@ def test_path_pattern():
         (Lookup.EQUAL, "y=2", "https://foo.bar/?x=1", False),
         (Lookup.EQUAL, {"x": ANY}, "https://foo.bar/?x=1", True),
         (Lookup.EQUAL, {"y": ANY}, "https://foo.bar/?x=1", False),
+        (Lookup.EQUAL, {}, "https://foo.bar/?x=1", False),
+        (Lookup.EQUAL, {}, "https://foo.bar/", True),
         (Lookup.EQUAL, "x=1&y=2", "https://foo.bar/?x=1", False),
         (Lookup.EQUAL, "y=2&x=1", "https://foo.bar/?x=1&y=2", True),
         (Lookup.EQUAL, "y=3&x=2&x=1", "https://foo.bar/?x=1&x=2&y=3", False),  # ordered