test(tools): add unit tests for SwitchModeTool

- Add comprehensive test suite for SwitchModeTool (18 tests)
- Cover mode slug validation (valid/invalid/missing)
- Test error propagation from mode loading
- Validate approval flow with correct params
- Test mode switching delegation to Controller
- Verify resolve() returns correct messages for both paths
- Follow existing test patterns from ask.spec.ts

Author: proyectoauraorg

src/core/tools/__tests__/switchModeTool.spec.ts

@@ -0,0 +1,381 @@
+import { describe, it, expect, vi, beforeEach } from "vitest"
+
+import type { Task } from "../../task/Task"
+import type { ToolUse } from "../../../shared/tools"
+import type { ToolCallbacks } from "../BaseTool"
+import { switchModeTool } from "../SwitchModeTool"
+import { formatResponse } from "../../prompts/responses"
+
+// Mock delay to avoid actual waits in tests
+vi.mock("delay", () => ({
+	default: vi.fn().mockResolvedValue(undefined),
+}))
+
+// Mock the modes module
+vi.mock("../../../shared/modes", async (importOriginal) => {
+	const actual = await importOriginal<typeof import("../../../shared/modes")>()
+	return {
+		...actual,
+		defaultModeSlug: "code",
+		getModeBySlug: vi.fn((slug: string, _customModes?: unknown[]) => {
+			const builtInModes: Record<string, { slug: string; name: string }> = {
+				code: { slug: "code", name: "Code" },
+				architect: { slug: "architect", name: "Architect" },
+				ask: { slug: "ask", name: "Ask" },
+				"custom-mode": { slug: "custom-mode", name: "Custom Mode" },
+			}
+			return builtInModes[slug]
+		}),
+	}
+})
+
+describe("SwitchModeTool", () => {
+	let mockTask: Task
+	let mockCallbacks: ToolCallbacks
+	let mockHandleModeSwitch: ReturnType<typeof vi.fn>
+	let mockGetState: ReturnType<typeof vi.fn>
+
+	beforeEach(() => {
+		vi.clearAllMocks()
+
+		mockHandleModeSwitch = vi.fn().mockResolvedValue(undefined)
+		mockGetState = vi.fn().mockResolvedValue({ mode: "code", customModes: [] })
+
+		mockTask = {
+			consecutiveMistakeCount: 0,
+			recordToolError: vi.fn(),
+			didToolFailInCurrentTurn: false,
+			sayAndCreateMissingParamError: vi.fn().mockResolvedValue("Missing parameter error"),
+			ask: vi.fn().mockResolvedValue({}),
+			providerRef: {
+				deref: vi.fn().mockReturnValue({
+					getState: mockGetState,
+					handleModeSwitch: mockHandleModeSwitch,
+				}),
+			},
+		} as unknown as Task
+
+		mockCallbacks = {
+			askApproval: vi.fn().mockResolvedValue(true),
+			handleError: vi.fn(),
+			pushToolResult: vi.fn(),
+		}
+	})
+
+	function createBlock(params: { mode_slug?: string; reason?: string }, partial = false): ToolUse<"switch_mode"> {
+		return {
+			type: "tool_use" as const,
+			name: "switch_mode" as const,
+			params,
+			partial,
+			nativeArgs: {
+				mode_slug: params.mode_slug ?? "",
+				reason: params.reason ?? "",
+			},
+		} as unknown as ToolUse<"switch_mode">
+	}
+
+	// ===== Parameter validation tests =====
+
+	it("should handle missing mode_slug parameter", async () => {
+		const block = createBlock({ mode_slug: "" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		expect(mockTask.consecutiveMistakeCount).toBe(1)
+		expect(mockTask.recordToolError).toHaveBeenCalledWith("switch_mode")
+		expect(mockTask.sayAndCreateMissingParamError).toHaveBeenCalledWith("switch_mode", "mode_slug")
+		expect(mockCallbacks.pushToolResult).toHaveBeenCalledWith("Missing parameter error")
+	})
+
+	it("should handle missing reason parameter without error (reason is optional)", async () => {
+		const block = createBlock({ mode_slug: "architect", reason: "" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		// Should not treat missing reason as an error — it's optional
+		expect(mockTask.sayAndCreateMissingParamError).not.toHaveBeenCalled()
+	})
+
+	// ===== Invalid mode tests =====
+
+	it("should handle invalid mode slug", async () => {
+		const block = createBlock({ mode_slug: "nonexistent-mode", reason: "testing" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		expect(mockTask.recordToolError).toHaveBeenCalledWith("switch_mode")
+		expect(mockTask.didToolFailInCurrentTurn).toBe(true)
+		expect(mockCallbacks.pushToolResult).toHaveBeenCalledWith(
+			formatResponse.toolError("Invalid mode: nonexistent-mode"),
+		)
+		// Should NOT attempt to switch or ask approval
+		expect(mockCallbacks.askApproval).not.toHaveBeenCalled()
+		expect(mockHandleModeSwitch).not.toHaveBeenCalled()
+	})
+
+	// ===== Already in mode tests =====
+
+	it("should handle switching to the same mode", async () => {
+		// Current mode is "code" (from mockGetState)
+		const block = createBlock({ mode_slug: "code", reason: "already here" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		expect(mockTask.recordToolError).toHaveBeenCalledWith("switch_mode")
+		expect(mockTask.didToolFailInCurrentTurn).toBe(true)
+		expect(mockCallbacks.pushToolResult).toHaveBeenCalledWith("Already in Code mode.")
+		// Should NOT ask approval or switch
+		expect(mockCallbacks.askApproval).not.toHaveBeenCalled()
+		expect(mockHandleModeSwitch).not.toHaveBeenCalled()
+	})
+
+	// ===== Approval denial tests =====
+
+	it("should handle user denying the approval", async () => {
+		;(mockCallbacks.askApproval as ReturnType<typeof vi.fn>).mockResolvedValue(false)
+
+		const block = createBlock({ mode_slug: "architect", reason: "need architecture view" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		// Should have asked for approval
+		expect(mockCallbacks.askApproval).toHaveBeenCalledWith(
+			"tool",
+			JSON.stringify({ tool: "switchMode", mode: "architect", reason: "need architecture view" }),
+		)
+		// But should NOT switch mode or push result
+		expect(mockHandleModeSwitch).not.toHaveBeenCalled()
+		expect(mockCallbacks.pushToolResult).not.toHaveBeenCalled()
+	})
+
+	// ===== Happy path tests =====
+
+	it("should successfully switch mode with reason", async () => {
+		const block = createBlock({ mode_slug: "architect", reason: "need to plan architecture" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		// Should have asked for approval with correct message
+		expect(mockCallbacks.askApproval).toHaveBeenCalledWith(
+			"tool",
+			JSON.stringify({
+				tool: "switchMode",
+				mode: "architect",
+				reason: "need to plan architecture",
+			}),
+		)
+
+		// Should have called handleModeSwitch with the target slug
+		expect(mockHandleModeSwitch).toHaveBeenCalledWith("architect")
+
+		// Should have pushed success result
+		expect(mockCallbacks.pushToolResult).toHaveBeenCalledWith(
+			"Successfully switched from Code mode to Architect mode because: need to plan architecture.",
+		)
+	})
+
+	it("should successfully switch mode without reason", async () => {
+		const block = createBlock({ mode_slug: "ask", reason: "" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		expect(mockCallbacks.askApproval).toHaveBeenCalledWith(
+			"tool",
+			JSON.stringify({ tool: "switchMode", mode: "ask", reason: "" }),
+		)
+
+		expect(mockHandleModeSwitch).toHaveBeenCalledWith("ask")
+
+		expect(mockCallbacks.pushToolResult).toHaveBeenCalledWith("Successfully switched from Code mode to Ask mode.")
+	})
+
+	it("should reset consecutive mistake count on success", async () => {
+		mockTask.consecutiveMistakeCount = 3
+
+		const block = createBlock({ mode_slug: "architect", reason: "test" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		expect(mockTask.consecutiveMistakeCount).toBe(0)
+	})
+
+	// ===== Edge case: providerRef is null =====
+
+	it("should proceed silently when providerRef deref returns undefined", async () => {
+		mockTask = {
+			...mockTask,
+			providerRef: {
+				deref: vi.fn().mockReturnValue(undefined),
+			},
+		} as unknown as Task
+
+		const block = createBlock({ mode_slug: "architect", reason: "test" })
+
+		// When deref returns undefined, optional chaining makes getState() and
+		// handleModeSwitch() no-ops. getModeBySlug still returns a valid mode,
+		// and currentMode falls back to defaultModeSlug. The tool proceeds
+		// without throwing — but the mode switch is a no-op.
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		// Should NOT call handleError (no exception thrown)
+		expect(mockCallbacks.handleError).not.toHaveBeenCalled()
+		// Should have asked for approval
+		expect(mockCallbacks.askApproval).toHaveBeenCalled()
+		// Should still push a success result (even though switch was a no-op)
+		expect(mockCallbacks.pushToolResult).toHaveBeenCalledWith(
+			"Successfully switched from Code mode to Architect mode because: test.",
+		)
+	})
+
+	// ===== Edge case: getState throws an error =====
+
+	it("should handle getState throwing an error", async () => {
+		const stateError = new Error("Provider state unavailable")
+		mockGetState.mockRejectedValue(stateError)
+
+		const block = createBlock({ mode_slug: "architect", reason: "test" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		// The error should be caught by the try/catch and reported via handleError
+		expect(mockCallbacks.handleError).toHaveBeenCalledWith("switching mode", stateError)
+		// Should NOT have asked for approval or attempted switch
+		expect(mockCallbacks.askApproval).not.toHaveBeenCalled()
+		expect(mockHandleModeSwitch).not.toHaveBeenCalled()
+	})
+
+	// ===== Edge case: getState returns null =====
+
+	it("should use defaultModeSlug when getState returns null", async () => {
+		mockGetState.mockResolvedValue(null)
+
+		const block = createBlock({ mode_slug: "architect", reason: "test" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		// Should fall back to defaultModeSlug ("code") and succeed
+		expect(mockCallbacks.pushToolResult).toHaveBeenCalledWith(
+			"Successfully switched from Code mode to Architect mode because: test.",
+		)
+	})
+
+	// ===== handleModeSwitch failure =====
+
+	it("should handle handleModeSwitch throwing an error", async () => {
+		const switchError = new Error("Failed to switch mode")
+		mockHandleModeSwitch.mockRejectedValue(switchError)
+
+		const block = createBlock({ mode_slug: "architect", reason: "test" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		// Should have asked for approval first
+		expect(mockCallbacks.askApproval).toHaveBeenCalled()
+		// Should have called handleModeSwitch (which throws)
+		expect(mockHandleModeSwitch).toHaveBeenCalledWith("architect")
+		// Error should be caught and reported
+		expect(mockCallbacks.handleError).toHaveBeenCalledWith("switching mode", switchError)
+	})
+
+	// ===== Partial message handling =====
+
+	it("should handle partial messages during streaming", async () => {
+		const block = createBlock({ mode_slug: "architect", reason: "streaming test" }, true)
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		// Should send partial message via task.ask
+		expect(mockTask.ask).toHaveBeenCalledWith(
+			"tool",
+			JSON.stringify({
+				tool: "switchMode",
+				mode: "architect",
+				reason: "streaming test",
+			}),
+			true,
+		)
+		// Should NOT execute the actual switch
+		expect(mockCallbacks.askApproval).not.toHaveBeenCalled()
+		expect(mockHandleModeSwitch).not.toHaveBeenCalled()
+	})
+
+	it("should handle partial messages with empty parameters", async () => {
+		const block = createBlock(
+			{ mode_slug: undefined as unknown as string, reason: undefined as unknown as string },
+			true,
+		)
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		expect(mockTask.ask).toHaveBeenCalledWith(
+			"tool",
+			JSON.stringify({
+				tool: "switchMode",
+				mode: "",
+				reason: "",
+			}),
+			true,
+		)
+	})
+
+	// ===== Custom mode support =====
+
+	it("should switch to a custom mode", async () => {
+		const block = createBlock({ mode_slug: "custom-mode", reason: "testing custom modes" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		expect(mockCallbacks.askApproval).toHaveBeenCalled()
+		expect(mockHandleModeSwitch).toHaveBeenCalledWith("custom-mode")
+		expect(mockCallbacks.pushToolResult).toHaveBeenCalledWith(
+			"Successfully switched from Code mode to Custom Mode mode because: testing custom modes.",
+		)
+	})
+
+	// ===== Message format tests =====
+
+	it("should format the approval message correctly", async () => {
+		const block = createBlock({ mode_slug: "ask", reason: "quick question" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		const expectedMessage = JSON.stringify({
+			tool: "switchMode",
+			mode: "ask",
+			reason: "quick question",
+		})
+
+		expect(mockCallbacks.askApproval).toHaveBeenCalledWith("tool", expectedMessage)
+	})
+
+	// ===== getState with custom modes =====
+
+	it("should read current mode from providerRef state", async () => {
+		// Set current mode to "architect"
+		mockGetState.mockResolvedValue({ mode: "architect", customModes: [] })
+
+		const block = createBlock({ mode_slug: "code", reason: "switching back" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		expect(mockHandleModeSwitch).toHaveBeenCalledWith("code")
+		expect(mockCallbacks.pushToolResult).toHaveBeenCalledWith(
+			"Successfully switched from Architect mode to Code mode because: switching back.",
+		)
+	})
+
+	it("should use defaultModeSlug when getState returns no mode", async () => {
+		mockGetState.mockResolvedValue({})
+
+		const block = createBlock({ mode_slug: "ask", reason: "test" })
+
+		await switchModeTool.handle(mockTask, block, mockCallbacks)
+
+		// defaultModeSlug is "code" (from mock)
+		// Should report switching from Code mode
+		expect(mockCallbacks.pushToolResult).toHaveBeenCalledWith(
+			"Successfully switched from Code mode to Ask mode because: test.",
+		)
+	})
+})