Implementation:Microsoft Semantic kernel OpenApi TestPlugin MessagesOpenAPI

Knowledge Sources	Microsoft_Semantic_kernel
Domains	OpenAPI, Testing, Microsoft_Graph
Last Updated	2026-02-11 00:00 GMT

Overview

OpenAPI v3.0.1 YAML test specification describing a subset of the Microsoft Graph OData messages API, used as test fixture data in the Functions unit tests of the Semantic Kernel .NET SDK.

Description

This YAML file is an OpenAPI v3.0.1 specification that models a subset of the Microsoft Graph v1.0 messages API. Unlike the Azure Key Vault test documents, this specification tests more complex real-world API patterns including OData query parameters, paginated collections, component references ($ref), and rich schema definitions for email message objects.

Key features of this specification:

GET /me/messages - List messages in the signed-in user's mailbox with OData query parameters ($top, $skip, $search, $filter, $count, $orderby, $select, $expand)
POST /me/sendMail - Send a mail message with a request body reference
Component schemas - Full microsoft.graph.message schema with properties like categories, changeKey, body content, recipients, and attachments
Component parameters - Reusable parameter definitions referenced via $ref
Component request bodies and responses - Shared definitions for message collections and send mail payloads
Pagination support via x-ms-pageable extension

Usage

This file is loaded during unit test execution to validate the OpenAPI parser's handling of complex real-world API specifications with component references, OData query conventions, and rich nested schemas. It exercises the parser's ability to resolve $ref pointers, handle paginated response collections, and extract operations from Graph-style API definitions.

Code Reference

Source Location

Repository: Microsoft_Semantic_kernel
File: dotnet/src/Functions/Functions.UnitTests/OpenApi/TestPlugins/messages-openapi.yml
Lines: 1-513

Signature

openapi: 3.0.1
info:
  title: OData Service for namespace microsoft.graph - Subset
  description: This OData service is located at https://graph.microsoft.com/v1.0
  version: v1.0
servers:
  - url: https://graph.microsoft.com/v1.0
paths:
  /me/messages:
    get:
      tags:
        - me.message
      summary: Get the messages in the signed-in user's mailbox
      operationId: me_ListMessages
      parameters:
        - name: includeHiddenMessages
          in: query
          description: Include Hidden Messages
          schema:
            type: string
        - $ref: '#/components/parameters/top'
        - $ref: '#/components/parameters/skip'

Import

// Load the Messages OpenAPI document in unit tests
var stream = Assembly.GetExecutingAssembly()
    .GetManifestResourceStream("messages-openapi.yml");

// Or read directly from the TestPlugins directory
var yaml = File.ReadAllText("OpenApi/TestPlugins/messages-openapi.yml");

I/O Contract

Inputs

Name	Type	Required	Description
includeHiddenMessages	string (query)	no	Include hidden messages in the response
$top	integer (query)	no	Limit the number of items returned (OData)
$skip	integer (query)	no	Skip the first N items (OData)
$search	string (query)	no	Search items by search phrases (OData)
$filter	string (query)	no	Filter items by property values (OData)
$count	boolean (query)	no	Include count of items (OData)
$orderby	array of string (query)	no	Order items by property values
$select	array of string (query)	no	Select properties to be returned
$expand	array of string (query)	no	Expand related entities
sendMailRequestBody	object (body)	yes (POST)	Mail message body for the sendMail action

Outputs

Name	Type	Description
messageCollectionResponse	object	Paginated collection of microsoft.graph.message objects with @odata.nextLink
microsoft.graph.message	object	Email message with id, categories, subject, body, sender, recipients, and attachments
204 (sendMail)	empty	Success response for the sendMail action

Usage Examples

Parsing the Messages OpenAPI Spec in a Unit Test

// Example: Loading and parsing the Messages OpenAPI YAML document
using var stream = File.OpenRead("OpenApi/TestPlugins/messages-openapi.yml");
var operations = await OpenApiDocumentParser.ParseAsync(stream);

// Verify the me_ListMessages operation was extracted
var listMessages = operations.First(op => op.Id == "me_ListMessages");
Assert.Equal("GET", listMessages.Method.ToString());
Assert.Equal("https://graph.microsoft.com/v1.0", listMessages.ServerUrl);

// Verify OData parameters are resolved from $ref
Assert.Contains(listMessages.Parameters, p => p.Name == "$top");
Assert.Contains(listMessages.Parameters, p => p.Name == "$filter");

// Verify sendMail operation
var sendMail = operations.First(op => op.Id == "me_sendMail");
Assert.Equal("POST", sendMail.Method.ToString());

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