Add test to demonstrate resolveArmResources API bug with multiple singletons

Co-authored-by: live1206 <[email protected]>

Author: Copilot

eng/packages/http-client-csharp-mgmt/emitter/test/resolve-arm-resources-bug.test.ts

@@ -0,0 +1,162 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+/**
+ * This test file demonstrates a bug in the resolveArmResources API from
+ * @azure-tools/typespec-azure-resource-manager.
+ *
+ * Bug Description:
+ * When multiple singleton resources are defined with different @singleton keys
+ * (e.g., Employee with default key and CurrentEmployee with "current" key),
+ * the resolveArmResources API does not properly distinguish between them.
+ * All resolved resources point to the same model type instead of their respective types.
+ *
+ * This test is marked with .skip because it demonstrates a bug in an external library
+ * that needs to be fixed before the test will pass.
+ */
+
+import { beforeEach, describe, it } from "vitest";
+import {
+  createEmitterTestHost,
+  typeSpecCompile
+} from "./test-util.js";
+import { TestHost } from "@typespec/compiler/testing";
+import { resolveArmResources } from "@azure-tools/typespec-azure-resource-manager";
+import { strictEqual, ok } from "assert";
+
+/**
+ * Shared TypeSpec schema for multiple singleton resources test.
+ * Defines two singleton resources with different @singleton keys.
+ */
+const multipleSingletonsSchema = `
+/** Employee properties */
+model EmployeeProperties {
+  /** Age of employee */
+  age?: int32;
+}
+
+/** An Employee singleton resource with default key */
+@singleton
+model Employee is TrackedResource<EmployeeProperties> {
+  ...ResourceNameParameter<Employee>;
+}
+
+/** A CurrentEmployee singleton resource with "current" key */
+@singleton("current")
+model CurrentEmployee is TrackedResource<EmployeeProperties> {
+  ...ResourceNameParameter<CurrentEmployee>;
+}
+
+interface Operations extends Azure.ResourceManager.Operations {}
+
+@armResourceOperations
+interface Employees {
+  get is ArmResourceRead<Employee>;
+  createOrUpdate is ArmResourceCreateOrReplaceAsync<Employee>;
+}
+
+@armResourceOperations
+interface CurrentEmployees {
+  get is ArmResourceRead<CurrentEmployee>;
+  createOrUpdate is ArmResourceCreateOrReplaceAsync<CurrentEmployee>;
+}
+`;
+
+describe("resolveArmResources API Bug Demonstration", () => {
+  let runner: TestHost;
+  beforeEach(async () => {
+    runner = await createEmitterTestHost();
+  });
+
+  /**
+   * This test demonstrates that resolveArmResources does not correctly return
+   * multiple singleton resources with different @singleton keys.
+   *
+   * Expected behavior: The API should return both Employee and CurrentEmployee
+   * as separate resources with their respective model types.
+   *
+   * Actual behavior: All resolved resources have type.name === "Employee",
+   * meaning CurrentEmployee is never properly identified.
+   */
+  it.skip("should return distinct resources for multiple singletons with different keys", async () => {
+    const program = await typeSpecCompile(multipleSingletonsSchema, runner);
+
+    // Use resolveArmResources API to get all resolved ARM resources
+    const provider = resolveArmResources(program);
+    const resolvedResources = provider.resources ?? [];
+
+    // Check that we have resources returned
+    ok(resolvedResources.length > 0, "Should have at least one resolved resource");
+
+    // Find resources by their model type name
+    const employeeResources = resolvedResources.filter(
+      (r) => r.type.name === "Employee"
+    );
+    const currentEmployeeResources = resolvedResources.filter(
+      (r) => r.type.name === "CurrentEmployee"
+    );
+
+    // BUG: This assertion fails because resolveArmResources returns all resources
+    // with type.name === "Employee" instead of distinguishing CurrentEmployee
+    ok(
+      currentEmployeeResources.length > 0,
+      "Should have at least one CurrentEmployee resource - BUG: resolveArmResources does not return CurrentEmployee"
+    );
+
+    // Verify that Employee resources are returned correctly
+    ok(
+      employeeResources.length > 0,
+      "Should have at least one Employee resource"
+    );
+
+    // Verify that the total count is correct (should be 2 distinct resources for CRUD operations)
+    // Note: The API may return multiple entries per resource for different operation paths
+    const uniqueResourceTypes = new Set(resolvedResources.map((r) => r.type.name));
+    strictEqual(
+      uniqueResourceTypes.size,
+      2,
+      "Should have exactly 2 unique resource types (Employee and CurrentEmployee)"
+    );
+  });
+
+  /**
+   * This test shows the current (buggy) behavior of resolveArmResources
+   * where all resources point to the same model type.
+   */
+  it("demonstrates current buggy behavior - all resources have same type", async () => {
+    const program = await typeSpecCompile(multipleSingletonsSchema, runner);
+
+    // Use resolveArmResources API to get all resolved ARM resources
+    const provider = resolveArmResources(program);
+    const resolvedResources = provider.resources ?? [];
+
+    // BUG: All resolved resources have type.name === "Employee"
+    // CurrentEmployee is never returned despite being defined
+    const allResourceTypeNames = resolvedResources.map((r) => r.type.name);
+    const uniqueResourceTypes = new Set(allResourceTypeNames);
+
+    // This assertion passes but demonstrates the bug:
+    // We expect 2 unique types but only get 1
+    strictEqual(
+      uniqueResourceTypes.size,
+      1,
+      "BUG: resolveArmResources only returns Employee type, missing CurrentEmployee"
+    );
+
+    // All resources point to Employee
+    ok(
+      allResourceTypeNames.every((name) => name === "Employee"),
+      "BUG: All resolved resources have type Employee"
+    );
+
+    // CurrentEmployee is never returned
+    const hasCurrentEmployee = allResourceTypeNames.some(
+      (name) => name === "CurrentEmployee"
+    );
+    strictEqual(
+      hasCurrentEmployee,
+      false,
+      "BUG: CurrentEmployee is never returned by resolveArmResources"
+    );
+  });
+});