refactor(tests): test-hygiene fixes for Agent test files

- Replace Record<string, unknown> return types on TanStack mock chunk
  builders with inferred types via as const
- Remove dynamic imports in converter-aisdk error tests — use
  top-level collectEventsIncludingErrors import instead
- Remove redundant as RunAgentInput casts in converter-tanstack-input
  tests (createDefaultInput already returns the correct type)
- Add comments explaining necessary casts in createAgent overloads
  (TypeScript limitation with discriminated union narrowing)

Author: AlemTuzlak

packages/runtime/src/agent/__tests__/agent-test-helpers.ts

@@ -43,7 +43,7 @@ export { Agent, type AgentFactoryContext };
  */
 export function createDefaultInput(
   overrides?: Partial<RunAgentInput>,
-): RunAgentInput {
+) {
   return {
     threadId: "test-thread",
     runId: "test-run",
@@ -61,31 +61,31 @@ export function createDefaultInput(
 // ---------------------------------------------------------------------------
 
 /** TanStack text content chunk */
-export function tanstackTextChunk(delta: string): Record<string, unknown> {
-  return { type: "TEXT_MESSAGE_CONTENT", delta };
+export function tanstackTextChunk(delta: string) {
+  return { type: "TEXT_MESSAGE_CONTENT", delta } as const;
 }
 
 /** TanStack tool call start chunk */
 export function tanstackToolCallStart(
   toolCallId: string,
   toolCallName: string,
-): Record<string, unknown> {
-  return { type: "TOOL_CALL_START", toolCallId, toolCallName };
+) {
+  return { type: "TOOL_CALL_START", toolCallId, toolCallName } as const;
 }
 
 /** TanStack tool call args chunk */
 export function tanstackToolCallArgs(
   toolCallId: string,
   delta: string,
-): Record<string, unknown> {
-  return { type: "TOOL_CALL_ARGS", toolCallId, delta };
+) {
+  return { type: "TOOL_CALL_ARGS", toolCallId, delta } as const;
 }
 
 /** TanStack tool call end chunk */
 export function tanstackToolCallEnd(
   toolCallId: string,
-): Record<string, unknown> {
-  return { type: "TOOL_CALL_END", toolCallId };
+) {
+  return { type: "TOOL_CALL_END", toolCallId } as const;
 }
 
 // ---------------------------------------------------------------------------
@@ -97,7 +97,7 @@ export function tanstackToolCallEnd(
  */
 export function mockTanStackStream(
   chunks: Record<string, unknown>[],
-): AsyncIterable<unknown> {
+) {
   return {
     [Symbol.asyncIterator]: async function* () {
       for (const chunk of chunks) {
@@ -155,6 +155,8 @@ export function createAgent(
 ): Agent {
   switch (type) {
     case "aisdk": {
+      // Cast needed: TypeScript's control-flow narrowing doesn't propagate
+      // through overload signatures to narrow the union parameter type.
       const events = streamData as MockStreamEvent[];
       return new Agent({
         type: "aisdk",
@@ -168,13 +170,15 @@ export function createAgent(
       });
     }
     case "tanstack": {
+      // Cast needed: same overload-narrowing limitation as above.
       const chunks = streamData as Record<string, unknown>[];
       return new Agent({
         type: "tanstack",
         factory: () => mockTanStackStream(chunks),
       });
     }
     case "custom": {
+      // Cast needed: same overload-narrowing limitation as above.
       const events = streamData as BaseEvent[];
       return new Agent({
         type: "custom",
@@ -258,7 +262,7 @@ export function createMidStreamErrorAgent(
               type: EventType.TEXT_MESSAGE_CHUNK,
               role: "assistant",
               delta: "partial",
-            } as BaseEvent;
+            } as const as BaseEvent;
             throw new Error(errorMessage);
           },
         }),

packages/runtime/src/agent/__tests__/converter-aisdk.test.ts

@@ -4,6 +4,7 @@ import {
   createAgent,
   createDefaultInput,
   collectEvents,
+  collectEventsIncludingErrors,
   expectLifecycleWrapped,
   expectEventSequence,
   eventField,
@@ -593,10 +594,9 @@ describe("AI SDK Converter", () => {
       ]);
       const input = createDefaultInput();
 
-      const { events, errored } =
-        await (await import("./agent-test-helpers")).collectEventsIncludingErrors(
-          agent.run(input),
-        );
+      const { events, errored } = await collectEventsIncludingErrors(
+        agent.run(input),
+      );
 
       expect(errored).toBe(true);
       const errorEvents = events.filter(
@@ -618,10 +618,9 @@ describe("AI SDK Converter", () => {
       ]);
       const input = createDefaultInput();
 
-      const { events, errored } =
-        await (await import("./agent-test-helpers")).collectEventsIncludingErrors(
-          agent.run(input),
-        );
+      const { events, errored } = await collectEventsIncludingErrors(
+        agent.run(input),
+      );
 
       expect(errored).toBe(true);
       const errorEvents = events.filter(
@@ -638,10 +637,9 @@ describe("AI SDK Converter", () => {
       ]);
       const input = createDefaultInput();
 
-      const { events, errored } =
-        await (await import("./agent-test-helpers")).collectEventsIncludingErrors(
-          agent.run(input),
-        );
+      const { events, errored } = await collectEventsIncludingErrors(
+        agent.run(input),
+      );
 
       expect(errored).toBe(true);
       const errorEvents = events.filter(

packages/runtime/src/agent/__tests__/converter-tanstack-input.test.ts

@@ -1,5 +1,4 @@
 import { describe, it, expect } from "vitest";
-import type { RunAgentInput } from "@ag-ui/client";
 import { convertInputToTanStackAI } from "../converters/tanstack";
 import { createDefaultInput } from "./agent-test-helpers";
 
@@ -14,7 +13,7 @@ describe("convertInputToTanStackAI", () => {
           { role: "system", content: "You are helpful" },
           { role: "user", content: "Hello" },
         ],
-      }) as RunAgentInput;
+      });
 
       const { messages } = convertInputToTanStackAI(input);
 
@@ -29,7 +28,7 @@ describe("convertInputToTanStackAI", () => {
           { role: "developer", content: "Internal instruction" },
           { role: "user", content: "Hi" },
         ],
-      }) as RunAgentInput;
+      });
 
       const { messages } = convertInputToTanStackAI(input);
 
@@ -44,7 +43,7 @@ describe("convertInputToTanStackAI", () => {
           { role: "developer", content: "Dev instruction" },
           { role: "user", content: "Hello" },
         ],
-      }) as RunAgentInput;
+      });
 
       const { systemPrompts } = convertInputToTanStackAI(input);
 
@@ -59,7 +58,7 @@ describe("convertInputToTanStackAI", () => {
           { role: "assistant", content: "Answer 1" },
           { role: "user", content: "Question 2" },
         ],
-      }) as RunAgentInput;
+      });
 
       const { messages } = convertInputToTanStackAI(input);
 
@@ -92,7 +91,7 @@ describe("convertInputToTanStackAI", () => {
             ],
           },
         ],
-      }) as RunAgentInput;
+      });
 
       const { messages } = convertInputToTanStackAI(input);
 
@@ -114,7 +113,7 @@ describe("convertInputToTanStackAI", () => {
             toolCallId: "tc-1",
           },
         ],
-      }) as RunAgentInput;
+      });
 
       const { messages } = convertInputToTanStackAI(input);
 
@@ -134,7 +133,7 @@ describe("convertInputToTanStackAI", () => {
           { description: "User preferences", value: "Dark mode enabled" },
           { description: "Current page", value: "/dashboard" },
         ],
-      }) as RunAgentInput;
+      });
 
       const { systemPrompts } = convertInputToTanStackAI(input);
 
@@ -145,7 +144,7 @@ describe("convertInputToTanStackAI", () => {
     });
 
     it("does not add context when context array is empty", () => {
-      const input = createDefaultInput({ context: [] }) as RunAgentInput;
+      const input = createDefaultInput({ context: [] });
 
       const { systemPrompts } = convertInputToTanStackAI(input);
 
@@ -160,7 +159,7 @@ describe("convertInputToTanStackAI", () => {
     it("serializes non-empty state into systemPrompts", () => {
       const input = createDefaultInput({
         state: { count: 42, items: ["a", "b"] },
-      }) as RunAgentInput;
+      });
 
       const { systemPrompts } = convertInputToTanStackAI(input);
 
@@ -172,7 +171,7 @@ describe("convertInputToTanStackAI", () => {
     });
 
     it("does not add state when state is empty object", () => {
-      const input = createDefaultInput({ state: {} }) as RunAgentInput;
+      const input = createDefaultInput({ state: {} });
 
       const { systemPrompts } = convertInputToTanStackAI(input);
 
@@ -182,7 +181,7 @@ describe("convertInputToTanStackAI", () => {
     });
 
     it("does not add state when state is null", () => {
-      const input = createDefaultInput({ state: null }) as RunAgentInput;
+      const input = createDefaultInput({ state: null });
 
       const { systemPrompts } = convertInputToTanStackAI(input);
 
@@ -197,7 +196,7 @@ describe("convertInputToTanStackAI", () => {
   // -------------------------------------------------------------------------
   describe("empty input", () => {
     it("returns empty messages and systemPrompts for default input", () => {
-      const input = createDefaultInput() as RunAgentInput;
+      const input = createDefaultInput();
 
       const { messages, systemPrompts } = convertInputToTanStackAI(input);