diff --git a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/message.proto b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/message.proto
index fa9f6f0f..5e31596f 100644
--- a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/message.proto
+++ b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/message.proto
@@ -75,6 +75,37 @@ service Messaging1 {
         ]
     };
   }
+
+  rpc StreamMessages(Message) returns(stream Message) {
+    option(google.api.http) = {
+        get: "/v1/stream/{message_id}"
+        body: "*"
+    };
+    option (openapi.v3.operation) = {
+      responses: {
+        response_or_reference: {
+          name: "200"
+          value: {
+            response : {
+              description: "OK"
+              content: {
+                additional_properties: {
+                  name: "text/event-stream"
+                  value: {
+                    schema: {
+                      reference: {
+                        _ref: "Message"
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    };
+  }
 }
 
 service Messaging2 {
diff --git a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi.yaml b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi.yaml
index b1e31f0f..c2df1a2e 100644
--- a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi.yaml
+++ b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi.yaml
@@ -46,6 +46,36 @@ paths:
                                 $ref: '#/components/schemas/Status'
             security:
                 - BasicAuth: []
+    /v1/stream/{message_id}:
+        get:
+            tags:
+                - Messaging1
+            operationId: Messaging1_StreamMessages
+            parameters:
+                - name: message_id
+                  in: path
+                  required: true
+                  schema:
+                    type: string
+            requestBody:
+                content:
+                    application/json:
+                        schema:
+                            $ref: '#/components/schemas/Message'
+                required: true
+            responses:
+                default:
+                    description: Default error response
+                    content:
+                        application/json:
+                            schema:
+                                $ref: '#/components/schemas/Status'
+                "200":
+                    description: OK
+                    content:
+                        text/event-stream:
+                            schema:
+                                $ref: '#/components/schemas/Message'
 components:
     schemas:
         GoogleProtobufAny:
diff --git a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_default_response.yaml b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_default_response.yaml
index b1e31f0f..c2df1a2e 100644
--- a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_default_response.yaml
+++ b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_default_response.yaml
@@ -46,6 +46,36 @@ paths:
                                 $ref: '#/components/schemas/Status'
             security:
                 - BasicAuth: []
+    /v1/stream/{message_id}:
+        get:
+            tags:
+                - Messaging1
+            operationId: Messaging1_StreamMessages
+            parameters:
+                - name: message_id
+                  in: path
+                  required: true
+                  schema:
+                    type: string
+            requestBody:
+                content:
+                    application/json:
+                        schema:
+                            $ref: '#/components/schemas/Message'
+                required: true
+            responses:
+                default:
+                    description: Default error response
+                    content:
+                        application/json:
+                            schema:
+                                $ref: '#/components/schemas/Status'
+                "200":
+                    description: OK
+                    content:
+                        text/event-stream:
+                            schema:
+                                $ref: '#/components/schemas/Message'
 components:
     schemas:
         GoogleProtobufAny:
diff --git a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_fq_schema_naming.yaml b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_fq_schema_naming.yaml
index 5dbbceca..2b25cb23 100644
--- a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_fq_schema_naming.yaml
+++ b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_fq_schema_naming.yaml
@@ -46,6 +46,36 @@ paths:
                                 $ref: '#/components/schemas/google.rpc.Status'
             security:
                 - BasicAuth: []
+    /v1/stream/{message_id}:
+        get:
+            tags:
+                - Messaging1
+            operationId: Messaging1_StreamMessages
+            parameters:
+                - name: message_id
+                  in: path
+                  required: true
+                  schema:
+                    type: string
+            requestBody:
+                content:
+                    application/json:
+                        schema:
+                            $ref: '#/components/schemas/tests.openapiv3annotations.message.v1.Message'
+                required: true
+            responses:
+                default:
+                    description: Default error response
+                    content:
+                        application/json:
+                            schema:
+                                $ref: '#/components/schemas/google.rpc.Status'
+                "200":
+                    description: OK
+                    content:
+                        text/event-stream:
+                            schema:
+                                $ref: '#/components/schemas/tests.openapiv3annotations.message.v1.Message'
 components:
     schemas:
         google.protobuf.Any:
diff --git a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_json.yaml b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_json.yaml
index b1e31f0f..c2df1a2e 100644
--- a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_json.yaml
+++ b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_json.yaml
@@ -46,6 +46,36 @@ paths:
                                 $ref: '#/components/schemas/Status'
             security:
                 - BasicAuth: []
+    /v1/stream/{message_id}:
+        get:
+            tags:
+                - Messaging1
+            operationId: Messaging1_StreamMessages
+            parameters:
+                - name: message_id
+                  in: path
+                  required: true
+                  schema:
+                    type: string
+            requestBody:
+                content:
+                    application/json:
+                        schema:
+                            $ref: '#/components/schemas/Message'
+                required: true
+            responses:
+                default:
+                    description: Default error response
+                    content:
+                        application/json:
+                            schema:
+                                $ref: '#/components/schemas/Status'
+                "200":
+                    description: OK
+                    content:
+                        text/event-stream:
+                            schema:
+                                $ref: '#/components/schemas/Message'
 components:
     schemas:
         GoogleProtobufAny:
diff --git a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_string_enum.yaml b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_string_enum.yaml
index b1e31f0f..c2df1a2e 100644
--- a/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_string_enum.yaml
+++ b/cmd/protoc-gen-openapi/examples/tests/openapiv3annotations/openapi_string_enum.yaml
@@ -46,6 +46,36 @@ paths:
                                 $ref: '#/components/schemas/Status'
             security:
                 - BasicAuth: []
+    /v1/stream/{message_id}:
+        get:
+            tags:
+                - Messaging1
+            operationId: Messaging1_StreamMessages
+            parameters:
+                - name: message_id
+                  in: path
+                  required: true
+                  schema:
+                    type: string
+            requestBody:
+                content:
+                    application/json:
+                        schema:
+                            $ref: '#/components/schemas/Message'
+                required: true
+            responses:
+                default:
+                    description: Default error response
+                    content:
+                        application/json:
+                            schema:
+                                $ref: '#/components/schemas/Status'
+                "200":
+                    description: OK
+                    content:
+                        text/event-stream:
+                            schema:
+                                $ref: '#/components/schemas/Message'
 components:
     schemas:
         GoogleProtobufAny:
diff --git a/cmd/protoc-gen-openapi/plugin_test.go b/cmd/protoc-gen-openapi/plugin_test.go
index 767e9742..2eaf3e42 100644
--- a/cmd/protoc-gen-openapi/plugin_test.go
+++ b/cmd/protoc-gen-openapi/plugin_test.go
@@ -105,9 +105,9 @@ func TestOpenAPIProtobufNaming(t *testing.T) {
 				}
 			} else {
 				// Verify that the generated spec matches our expected version.
-				err = exec.Command("diff", TEMP_FILE, fixture).Run()
+				output, err := exec.Command("diff", TEMP_FILE, fixture).CombinedOutput()
 				if err != nil {
-					t.Fatalf("Diff failed: %+v", err)
+					t.Fatalf("Diff failed: %s", output)
 				}
 			}
 			// if the test succeeded, clean up
@@ -163,9 +163,9 @@ func TestOpenAPIFQSchemaNaming(t *testing.T) {
 				}
 			} else {
 				// Verify that the generated spec matches our expected version.
-				err = exec.Command("diff", TEMP_FILE, fixture).Run()
+				output, err := exec.Command("diff", TEMP_FILE, fixture).CombinedOutput()
 				if err != nil {
-					t.Fatalf("Diff failed: %+v", err)
+					t.Fatalf("Diff failed: %s", output)
 				}
 				// Verify that the generated spec matches the source_relative version
 				sourceRelativeFile := strings.TrimSuffix(tt.protofile, filepath.Ext(tt.protofile)) + ".openapi.yaml"
@@ -207,9 +207,9 @@ func TestOpenAPIJSONNaming(t *testing.T) {
 				}
 			} else {
 				// Verify that the generated spec matches our expected version.
-				err = exec.Command("diff", TEMP_FILE, fixture).Run()
+				output, err := exec.Command("diff", TEMP_FILE, fixture).CombinedOutput()
 				if err != nil {
-					t.Fatalf("Diff failed: %+v", err)
+					t.Fatalf("Diff failed: %s", output)
 				}
 			}
 			// if the test succeeded, clean up
@@ -244,9 +244,9 @@ func TestOpenAPIStringEnums(t *testing.T) {
 				}
 			} else {
 				// Verify that the generated spec matches our expected version.
-				err = exec.Command("diff", TEMP_FILE, fixture).Run()
+				output, err := exec.Command("diff", TEMP_FILE, fixture).CombinedOutput()
 				if err != nil {
-					t.Fatalf("diff failed: %+v", err)
+					t.Fatalf("diff failed: %s", output)
 				}
 			}
 			// if the test succeeded, clean up
@@ -281,9 +281,9 @@ func TestOpenAPIDefaultResponse(t *testing.T) {
 				}
 			} else {
 				// Verify that the generated spec matches our expected version.
-				err = exec.Command("diff", TEMP_FILE, fixture).Run()
+				output, err := exec.Command("diff", TEMP_FILE, fixture).CombinedOutput()
 				if err != nil {
-					t.Fatalf("diff failed: %+v", err)
+					t.Fatalf("diff failed: %s", output)
 				}
 			}
 			// if the test succeeded, clean up