Allow empty value with default

openapi_core/wrappers.py

@@ -70,7 +70,7 @@ class RequestParametersFactory(BaseRequestFactory):
                 if param.required:
                     raise
 
-                if not param.schema or not param.schema.default:
+                if not param.schema or param.schema.default is None:
                     continue
                 raw_value = param.schema.default
 

tests/integration/data/v3.0/petstore.yaml

@@ -34,6 +34,13 @@ paths:
             type: integer
             format: int32
             nullable: true
+        - name: search
+          in: query
+          description: Search query
+          schema:
+            type: string
+            default: ""
+          allowEmptyValue: true
         - name: ids
           in: query
           description: Filter pets with Ids

tests/integration/test_petstore.py

@@ -137,6 +137,7 @@ class TestPetstore(object):
             'query': {
                 'limit': 20,
                 'page': 1,
+                'search': '',
                 'ids': [12, 13],
             }
         }
@@ -212,6 +213,7 @@ class TestPetstore(object):
             'query': {
                 'limit': None,
                 'page': 1,
+                'search': '',
             }
         }