fix: Precedence of produces keywords for Swagger 2.0 schemas (#464)

docs/changelog.rst

@@ -6,6 +6,12 @@ Changelog
 `Unreleased`_
 -------------
 
+Fixed
+~~~~~
+
+- Precedence of ``produces`` keywords for Swagger 2.0 schemas. Now, operation-level ``produces`` overrides
+  schema-level ``produces`` as specified in the specification. `#463`_
+
 `1.0.2`_ - 2020-04-02
 ---------------------
 
@@ -829,6 +835,7 @@ Fixed
 .. _0.3.0: https://github.com/kiwicom/schemathesis/compare/v0.2.0...v0.3.0
 .. _0.2.0: https://github.com/kiwicom/schemathesis/compare/v0.1.0...v0.2.0
 
+.. _#463: https://github.com/kiwicom/schemathesis/issues/463
 .. _#457: https://github.com/kiwicom/schemathesis/issues/457
 .. _#451: https://github.com/kiwicom/schemathesis/issues/451
 .. _#450: https://github.com/kiwicom/schemathesis/issues/450

src/schemathesis/checks.py

@@ -45,11 +45,10 @@ def _expand_responses(responses: Dict[Union[str, int], Any]) -> Generator[int, N
 
 
 def content_type_conformance(response: GenericResponse, case: "Case") -> None:
+    produces = case.endpoint.definition.get("produces", None)
     global_produces = case.endpoint.schema.raw_schema.get("produces", None)
-    if global_produces:
+    if global_produces and not produces:
         produces = global_produces
-    else:
-        produces = case.endpoint.definition.get("produces", None)
     if not produces:
         return
     content_type = response.headers["Content-Type"]

test/runner/test_checks.py

@@ -3,6 +3,7 @@
 import pytest
 import requests
 
+import schemathesis
 from schemathesis import models
 from schemathesis.checks import (
     content_type_conformance,
@@ -49,6 +50,39 @@ def test_content_type_conformance_valid(response, case):
     assert content_type_conformance(response, case) is None
 
 
+@pytest.mark.parametrize("content_type, is_error", (("application/json", False), ("application/xml", True),))
+def test_global_produces_override(content_type, is_error):
+    # When "produces" is specified on the schema level and on the operation level
+    schema = schemathesis.from_dict(
+        {
+            "swagger": "2.0",
+            "info": {"title": "Sample API", "description": "API description in Markdown.", "version": "1.0.0"},
+            "host": "api.example.com",
+            "basePath": "/v1",
+            "schemes": ["https"],
+            "produces": ["application/xml"],
+            "paths": {
+                "/users": {
+                    "get": {
+                        "summary": "Returns a list of users.",
+                        "description": "Optional extended description in Markdown.",
+                        "produces": ["application/json"],
+                        "responses": {"200": {"description": "OK"}},
+                    }
+                }
+            },
+        }
+    )
+    endpoint = schema.endpoints["/v1/users"]["get"]
+    case = models.Case(endpoint)
+    response = make_response(content_type=content_type)
+    if not is_error:
+        assert content_type_conformance(response, case) is None
+    else:
+        with pytest.raises(AssertionError):
+            content_type_conformance(response, case)
+
+
 @pytest.mark.parametrize("value", (500, 502))
 def test_not_a_server_error(value, swagger_20):
     response = make_response()