fix(tests): remove unused createMockStream helpers from abort signal tests (#404)

CodeRabbit nitpick: three test cases had duplicate unused helper functions
(createMockStream + mockUsage) that were never called. Removed dead code and
inlined the usage Promise directly in each mockReturnValue call.

Author: easonliang28

src/api/providers/__tests__/openai-compatible-abort-signal.spec.ts

@@ -70,20 +70,9 @@ describe("OpenAICompatibleHandler abort signal", () => {
 				yield { type: "text-delta", text: "Test response" }
 			}
 
-			function createMockStream(yieldValue: any) {
-				return {
-					fullStream: (async function* () {
-						yield yieldValue
-					})(),
-					usage: Promise.resolve({ inputTokens: 10, outputTokens: 5 }),
-				}
-			}
-
-			const mockUsage = Promise.resolve({ inputTokens: 10, outputTokens: 5 })
-
 			mockStreamText.mockReturnValue({
 				fullStream: mockFullStream(),
-				usage: mockUsage,
+				usage: Promise.resolve({ inputTokens: 10, outputTokens: 5 }),
 			})
 
 			await handler
@@ -105,20 +94,9 @@ describe("OpenAICompatibleHandler abort signal", () => {
 				yield { type: "text-delta", text: "Test response" }
 			}
 
-			function createMockStream(yieldValue: any) {
-				return {
-					fullStream: (async function* () {
-						yield yieldValue
-					})(),
-					usage: Promise.resolve({ inputTokens: 10, outputTokens: 5 }),
-				}
-			}
-
-			const mockUsage = Promise.resolve({ inputTokens: 10, outputTokens: 5 })
-
 			mockStreamText.mockReturnValue({
 				fullStream: mockFullStream(),
-				usage: mockUsage,
+				usage: Promise.resolve({ inputTokens: 10, outputTokens: 5 }),
 			})
 
 			await handler
@@ -139,20 +117,9 @@ describe("OpenAICompatibleHandler abort signal", () => {
 				yield { type: "text-delta", text: "Test response" }
 			}
 
-			function createMockStream(yieldValue: any) {
-				return {
-					fullStream: (async function* () {
-						yield yieldValue
-					})(),
-					usage: Promise.resolve({ inputTokens: 10, outputTokens: 5 }),
-				}
-			}
-
-			const mockUsage = Promise.resolve({ inputTokens: 10, outputTokens: 5 })
-
 			mockStreamText.mockReturnValue({
 				fullStream: mockFullStream(),
-				usage: mockUsage,
+				usage: Promise.resolve({ inputTokens: 10, outputTokens: 5 }),
 			})
 
 			await handler.createMessage(systemPrompt, messages).next()