From 08ef04abcad7d2faa0fd1f787e115a198d14acfd Mon Sep 17 00:00:00 2001
From: Simon Schulte <github@neokil.de>
Date: Fri, 27 Mar 2026 11:14:20 +0100
Subject: [PATCH 1/2] fix(csharp): qualify model return types in generated
 tests to avoid standard library name collisions

When a model class shares a name with a .NET standard library type (e.g.
`Attributes`), the generated `Assert.IsType<Attributes>(model)` call is
ambiguous and fails to compile. Use the fully-qualified type name
`{{packageName}}.{{modelPackage}}.{{{.}}}` for model return types so the
generated test code is unambiguous regardless of model naming.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 .../libraries/generichost/api_test.mustache   |  5 +++
 .../3_0/csharp/model-name-collision.yaml      | 36 +++++++++++++++++++
 2 files changed, 41 insertions(+)
 create mode 100644 modules/openapi-generator/src/test/resources/3_0/csharp/model-name-collision.yaml

diff --git a/modules/openapi-generator/src/main/resources/csharp/libraries/generichost/api_test.mustache b/modules/openapi-generator/src/main/resources/csharp/libraries/generichost/api_test.mustache
index 32eb2b769f31..f69bf0bceef5 100644
--- a/modules/openapi-generator/src/main/resources/csharp/libraries/generichost/api_test.mustache
+++ b/modules/openapi-generator/src/main/resources/csharp/libraries/generichost/api_test.mustache
@@ -42,7 +42,12 @@ namespace {{packageName}}.Test.{{apiPackage}}
             {{#dataType}}
             var response = await _instance.{{operationId}}Async({{#allParams}}{{paramName}}{{^-last}}, {{/-last}}{{/allParams}});
             var model = response.{{vendorExtensions.x-http-status}}();
+            {{#isModel}}
+            Assert.IsType<{{packageName}}.{{modelPackage}}.{{{.}}}>(model);
+            {{/isModel}}
+            {{^isModel}}
             Assert.IsType<{{{.}}}>(model);
+            {{/isModel}}
             {{/dataType}}
             {{^dataType}}
             await _instance.{{operationId}}Async({{#allParams}}{{paramName}}{{^-last}}, {{/-last}}{{/allParams}});
diff --git a/modules/openapi-generator/src/test/resources/3_0/csharp/model-name-collision.yaml b/modules/openapi-generator/src/test/resources/3_0/csharp/model-name-collision.yaml
new file mode 100644
index 000000000000..d3c243a8a61c
--- /dev/null
+++ b/modules/openapi-generator/src/test/resources/3_0/csharp/model-name-collision.yaml
@@ -0,0 +1,36 @@
+openapi: 3.0.0
+info:
+  title: Model Name Collision Test
+  description: >-
+    Tests that generated test code uses fully-qualified type names for model
+    return types to avoid collisions with standard library classes (e.g. a
+    model named "Attributes" would conflict with System.Attribute).
+  version: 1.0.0
+  license:
+    name: Apache-2.0
+    url: 'https://www.apache.org/licenses/LICENSE-2.0.html'
+paths:
+  /resources:
+    get:
+      operationId: GetResources
+      tags:
+        - Resources
+      responses:
+        '200':
+          description: Returns a resource with attributes
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Attributes'
+servers:
+  - url: 'http://localhost'
+components:
+  schemas:
+    Attributes:
+      type: object
+      properties:
+        id:
+          type: integer
+          format: int32
+        name:
+          type: string

From a367d8df8d45a3cdc5bfb7b9fe4082c555ac4fe3 Mon Sep 17 00:00:00 2001
From: Simon Schulte <github@neokil.de>
Date: Tue, 7 Apr 2026 12:58:52 +0200
Subject: [PATCH 2/2] remove additional yaml test file

---
 .../3_0/csharp/model-name-collision.yaml      | 36 -------------------
 1 file changed, 36 deletions(-)
 delete mode 100644 modules/openapi-generator/src/test/resources/3_0/csharp/model-name-collision.yaml

diff --git a/modules/openapi-generator/src/test/resources/3_0/csharp/model-name-collision.yaml b/modules/openapi-generator/src/test/resources/3_0/csharp/model-name-collision.yaml
deleted file mode 100644
index d3c243a8a61c..000000000000
--- a/modules/openapi-generator/src/test/resources/3_0/csharp/model-name-collision.yaml
+++ /dev/null
@@ -1,36 +0,0 @@
-openapi: 3.0.0
-info:
-  title: Model Name Collision Test
-  description: >-
-    Tests that generated test code uses fully-qualified type names for model
-    return types to avoid collisions with standard library classes (e.g. a
-    model named "Attributes" would conflict with System.Attribute).
-  version: 1.0.0
-  license:
-    name: Apache-2.0
-    url: 'https://www.apache.org/licenses/LICENSE-2.0.html'
-paths:
-  /resources:
-    get:
-      operationId: GetResources
-      tags:
-        - Resources
-      responses:
-        '200':
-          description: Returns a resource with attributes
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/schemas/Attributes'
-servers:
-  - url: 'http://localhost'
-components:
-  schemas:
-    Attributes:
-      type: object
-      properties:
-        id:
-          type: integer
-          format: int32
-        name:
-          type: string