Address reviewer feedback: check plural examples in getSchemaExample

- Fall back to first entry of `examples` array when `example` is absent,
  fixing schema example extraction for OAS 3.1 specs.
- Add unit tests for plural and singular example precedence via
  TestableFastAPICodegen helper subclass.
- Add nickname property with examples array to test fixture.

Author: Goopher

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPythonCodegen.java

@@ -683,7 +683,15 @@ private Object getSchemaExample(String jsonSchema) {
         }
         try {
             Map<String, Object> schema = Json.mapper().readValue(jsonSchema, Map.class);
-            return schema.get("example");
+            Object example = schema.get("example");
+            if (example != null) {
+                return example;
+            }
+            Object examples = schema.get("examples");
+            if (examples instanceof List && !((List<?>) examples).isEmpty()) {
+                return ((List<?>) examples).get(0);
+            }
+            return null;
         } catch (Exception e) {
             return null;
         }

modules/openapi-generator/src/test/java/org/openapitools/codegen/python/PythonFastAPIServerCodegenTest.java

@@ -4,6 +4,7 @@
 import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.parser.core.models.ParseOptions;
 import org.openapitools.codegen.ClientOptInput;
+import org.openapitools.codegen.CodegenProperty;
 import org.openapitools.codegen.DefaultCodegen;
 import org.openapitools.codegen.DefaultGenerator;
 import org.openapitools.codegen.languages.PythonFastAPIServerCodegen;
@@ -24,6 +25,13 @@
 
 public class PythonFastAPIServerCodegenTest {
 
+    /** Exposes protected toPythonExample for unit testing. */
+    private static class TestableFastAPICodegen extends PythonFastAPIServerCodegen {
+        public String exposeToPythonExample(CodegenProperty cp) {
+            return toPythonExample(cp);
+        }
+    }
+
     // Helper function, intended to reduce boilerplate
     static private String generateFiles(DefaultCodegen codegen, String filePath) throws IOException {
         final File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
@@ -77,4 +85,24 @@ public void testSchemaPropertyExamplesInMetadata() throws IOException {
         assertFileContains(model, "name: StrictStr = Field(json_schema_extra={\"examples\": [\"doggie\"]})");
         assertFileNotContains(model, "json_schema_extra={\"examples\": [\"''\"]}");
     }
+
+    @Test(description = "toPythonExample picks first entry from plural examples array in jsonSchema")
+    public void testToPythonExampleWithPluralExamples() {
+        final TestableFastAPICodegen codegen = new TestableFastAPICodegen();
+        CodegenProperty cp = new CodegenProperty();
+        cp.name = "nickname";
+        cp.jsonSchema = "{\"type\": \"string\", \"examples\": [\"buddy\", \"pal\"]}";
+
+        Assert.assertEquals(codegen.exposeToPythonExample(cp), "\"buddy\"");
+    }
+
+    @Test(description = "toPythonExample prefers singular example over plural examples in jsonSchema")
+    public void testToPythonExamplePrefersExampleOverExamples() {
+        final TestableFastAPICodegen codegen = new TestableFastAPICodegen();
+        CodegenProperty cp = new CodegenProperty();
+        cp.name = "nickname";
+        cp.jsonSchema = "{\"type\": \"string\", \"example\": \"doggie\", \"examples\": [\"buddy\", \"pal\"]}";
+
+        Assert.assertEquals(codegen.exposeToPythonExample(cp), "\"doggie\"");
+    }
 }

modules/openapi-generator/src/test/resources/3_0/python-fastapi/petstore-with-examples.yaml

@@ -1406,6 +1406,12 @@ components:
         name:
           type: string
           example: doggie
+        nickname:
+          type: string
+          description: Optional nickname for the pet
+          examples:
+            - buddy
+            - pal
         photoUrls:
           type: array
           xml: