diff --git a/frontend/src/App.test.tsx b/frontend/src/App.test.tsx
new file mode 100644
index 0000000..a949750
--- /dev/null
+++ b/frontend/src/App.test.tsx
@@ -0,0 +1,158 @@
+import { render, screen, waitFor } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { api } from "./api/client";
+
+vi.mock("./api/client", () => {
+	const api = {
+		getCurrentProject: vi.fn(),
+		getKnownProjects: vi.fn(),
+		getHomeDirectory: vi.fn(),
+		openProject: vi.fn(),
+		closeProject: vi.fn(),
+		forgetKnownProject: vi.fn(),
+		listDirectoryAbsolute: vi.fn(),
+		getOllamaModels: vi.fn(),
+		getAnthropicApiKeyExists: vi.fn(),
+		getAnthropicModels: vi.fn(),
+		getModelPreference: vi.fn(),
+		setModelPreference: vi.fn(),
+		cancelChat: vi.fn(),
+		setAnthropicApiKey: vi.fn(),
+	};
+	class ChatWebSocket {
+		connect() {}
+		close() {}
+		sendChat() {}
+		cancel() {}
+	}
+	return { api, ChatWebSocket };
+});
+
+vi.mock("./api/workflow", () => {
+	return {
+		workflowApi: {
+			getAcceptance: vi.fn().mockResolvedValue({
+				can_accept: false,
+				reasons: [],
+				warning: null,
+				summary: { total: 0, passed: 0, failed: 0 },
+				missing_categories: [],
+			}),
+			getReviewQueueAll: vi.fn().mockResolvedValue({ stories: [] }),
+			recordTests: vi.fn(),
+			ensureAcceptance: vi.fn(),
+			getReviewQueue: vi.fn(),
+		},
+	};
+});
+
+const mockedApi = vi.mocked(api);
+
+describe("App", () => {
+	beforeEach(() => {
+		vi.resetModules();
+		vi.clearAllMocks();
+		mockedApi.getKnownProjects.mockResolvedValue([]);
+		mockedApi.getHomeDirectory.mockResolvedValue("/home/user");
+		mockedApi.listDirectoryAbsolute.mockResolvedValue([]);
+		mockedApi.getOllamaModels.mockResolvedValue([]);
+		mockedApi.getAnthropicApiKeyExists.mockResolvedValue(false);
+		mockedApi.getAnthropicModels.mockResolvedValue([]);
+		mockedApi.getModelPreference.mockResolvedValue(null);
+	});
+
+	async function renderApp() {
+		const { default: App } = await import("./App");
+		return render(<App />);
+	}
+
+	it("renders the selection screen when no project is open", async () => {
+		await renderApp();
+
+		await waitFor(() => {
+			expect(
+				screen.getByPlaceholderText(/\/path\/to\/project/i),
+			).toBeInTheDocument();
+		});
+	});
+
+	it("populates path input with home directory", async () => {
+		mockedApi.getHomeDirectory.mockResolvedValue("/Users/dave");
+
+		await renderApp();
+
+		await waitFor(() => {
+			const input = screen.getByPlaceholderText(
+				/\/path\/to\/project/i,
+			) as HTMLInputElement;
+			expect(input.value).toBe("/Users/dave/");
+		});
+	});
+
+	it("opens project and shows chat view", async () => {
+		mockedApi.openProject.mockResolvedValue("/home/user/myproject");
+
+		await renderApp();
+
+		await waitFor(() => {
+			expect(
+				screen.getByPlaceholderText(/\/path\/to\/project/i),
+			).toBeInTheDocument();
+		});
+
+		const input = screen.getByPlaceholderText(
+			/\/path\/to\/project/i,
+		) as HTMLInputElement;
+		await userEvent.clear(input);
+		await userEvent.type(input, "/home/user/myproject");
+
+		const openButton = screen.getByRole("button", { name: /open project/i });
+		await userEvent.click(openButton);
+
+		await waitFor(() => {
+			expect(mockedApi.openProject).toHaveBeenCalledWith(
+				"/home/user/myproject",
+			);
+		});
+	});
+
+	it("shows error when openProject fails", async () => {
+		mockedApi.openProject.mockRejectedValue(new Error("Path does not exist"));
+
+		await renderApp();
+
+		await waitFor(() => {
+			expect(
+				screen.getByPlaceholderText(/\/path\/to\/project/i),
+			).toBeInTheDocument();
+		});
+
+		const input = screen.getByPlaceholderText(
+			/\/path\/to\/project/i,
+		) as HTMLInputElement;
+		await userEvent.clear(input);
+		await userEvent.type(input, "/bad/path");
+
+		const openButton = screen.getByRole("button", { name: /open project/i });
+		await userEvent.click(openButton);
+
+		await waitFor(() => {
+			expect(screen.getByText(/Path does not exist/)).toBeInTheDocument();
+		});
+	});
+
+	it("shows known projects list", async () => {
+		mockedApi.getKnownProjects.mockResolvedValue([
+			"/home/user/project1",
+			"/home/user/project2",
+		]);
+
+		await renderApp();
+
+		await waitFor(() => {
+			expect(screen.getByTitle("/home/user/project1")).toBeInTheDocument();
+			expect(screen.getByTitle("/home/user/project2")).toBeInTheDocument();
+		});
+	});
+});
diff --git a/frontend/src/components/GatePanel.test.tsx b/frontend/src/components/GatePanel.test.tsx
new file mode 100644
index 0000000..fa53004
--- /dev/null
+++ b/frontend/src/components/GatePanel.test.tsx
@@ -0,0 +1,145 @@
+import { render, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { describe, expect, it, vi } from "vitest";
+import { GatePanel } from "./GatePanel";
+
+const baseProps = {
+	gateState: null,
+	gateStatusLabel: "Unknown",
+	gateStatusColor: "#aaa",
+	isGateLoading: false,
+	gateError: null,
+	lastGateRefresh: null,
+	onRefresh: vi.fn(),
+};
+
+describe("GatePanel", () => {
+	it("shows 'no workflow data' when gateState is null", () => {
+		render(<GatePanel {...baseProps} />);
+		expect(screen.getByText("No workflow data yet.")).toBeInTheDocument();
+	});
+
+	it("shows loading message when isGateLoading is true", () => {
+		render(<GatePanel {...baseProps} isGateLoading={true} />);
+		expect(
+			screen.getByText("Loading workflow gates..."),
+		).toBeInTheDocument();
+	});
+
+	it("shows error with retry button", async () => {
+		const onRefresh = vi.fn();
+		render(
+			<GatePanel
+				{...baseProps}
+				gateError="Connection failed"
+				onRefresh={onRefresh}
+			/>,
+		);
+
+		expect(screen.getByText("Connection failed")).toBeInTheDocument();
+
+		const retryButton = screen.getByRole("button", { name: "Retry" });
+		await userEvent.click(retryButton);
+		expect(onRefresh).toHaveBeenCalledOnce();
+	});
+
+	it("shows gate status label and color", () => {
+		render(
+			<GatePanel
+				{...baseProps}
+				gateStatusLabel="Blocked"
+				gateStatusColor="#ff7b72"
+			/>,
+		);
+		expect(screen.getByText("Blocked")).toBeInTheDocument();
+	});
+
+	it("shows test summary when gateState is provided", () => {
+		render(
+			<GatePanel
+				{...baseProps}
+				gateState={{
+					canAccept: true,
+					reasons: [],
+					warning: null,
+					summary: { total: 5, passed: 5, failed: 0 },
+					missingCategories: [],
+				}}
+				gateStatusLabel="Ready to accept"
+			/>,
+		);
+		expect(
+			screen.getByText(/5\/5 passing, 0 failing/),
+		).toBeInTheDocument();
+	});
+
+	it("shows missing categories", () => {
+		render(
+			<GatePanel
+				{...baseProps}
+				gateState={{
+					canAccept: false,
+					reasons: [],
+					warning: null,
+					summary: { total: 0, passed: 0, failed: 0 },
+					missingCategories: ["unit", "integration"],
+				}}
+			/>,
+		);
+		expect(
+			screen.getByText("Missing: unit, integration"),
+		).toBeInTheDocument();
+	});
+
+	it("shows warning text", () => {
+		render(
+			<GatePanel
+				{...baseProps}
+				gateState={{
+					canAccept: false,
+					reasons: [],
+					warning: "Multiple tests failing — fix one at a time.",
+					summary: { total: 4, passed: 2, failed: 2 },
+					missingCategories: [],
+				}}
+			/>,
+		);
+		expect(
+			screen.getByText("Multiple tests failing — fix one at a time."),
+		).toBeInTheDocument();
+	});
+
+	it("shows reasons as list items", () => {
+		render(
+			<GatePanel
+				{...baseProps}
+				gateState={{
+					canAccept: false,
+					reasons: ["No approved test plan.", "Tests are failing."],
+					warning: null,
+					summary: { total: 2, passed: 1, failed: 1 },
+					missingCategories: [],
+				}}
+			/>,
+		);
+		expect(
+			screen.getByText("No approved test plan."),
+		).toBeInTheDocument();
+		expect(screen.getByText("Tests are failing.")).toBeInTheDocument();
+	});
+
+	it("calls onRefresh when Refresh button is clicked", async () => {
+		const onRefresh = vi.fn();
+		render(<GatePanel {...baseProps} onRefresh={onRefresh} />);
+
+		await userEvent.click(
+			screen.getByRole("button", { name: "Refresh" }),
+		);
+		expect(onRefresh).toHaveBeenCalledOnce();
+	});
+
+	it("disables Refresh button when loading", () => {
+		render(<GatePanel {...baseProps} isGateLoading={true} />);
+		expect(screen.getByRole("button", { name: "Refresh" })).toBeDisabled();
+	});
+});
diff --git a/frontend/src/components/ReviewPanel.test.tsx b/frontend/src/components/ReviewPanel.test.tsx
new file mode 100644
index 0000000..00e00bb
--- /dev/null
+++ b/frontend/src/components/ReviewPanel.test.tsx
@@ -0,0 +1,157 @@
+import { render, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { describe, expect, it, vi } from "vitest";
+import type { ReviewStory } from "../api/workflow";
+import { ReviewPanel } from "./ReviewPanel";
+
+const readyStory: ReviewStory = {
+	story_id: "29_backfill_tests",
+	can_accept: true,
+	reasons: [],
+	warning: null,
+	summary: { total: 5, passed: 5, failed: 0 },
+	missing_categories: [],
+};
+
+const blockedStory: ReviewStory = {
+	story_id: "26_tdd_gates",
+	can_accept: false,
+	reasons: ["2 tests are failing."],
+	warning: "Multiple tests failing — fix one at a time.",
+	summary: { total: 5, passed: 3, failed: 2 },
+	missing_categories: [],
+};
+
+const baseProps = {
+	reviewQueue: [] as ReviewStory[],
+	isReviewLoading: false,
+	reviewError: null,
+	proceedingStoryId: null,
+	storyId: "",
+	isGateLoading: false,
+	proceedError: null,
+	proceedSuccess: null,
+	lastReviewRefresh: null,
+	onRefresh: vi.fn(),
+	onProceed: vi.fn().mockResolvedValue(undefined),
+};
+
+describe("ReviewPanel", () => {
+	it("shows empty state when no stories", () => {
+		render(<ReviewPanel {...baseProps} />);
+		expect(
+			screen.getByText("No stories waiting for review."),
+		).toBeInTheDocument();
+	});
+
+	it("shows loading state", () => {
+		render(<ReviewPanel {...baseProps} isReviewLoading={true} />);
+		expect(screen.getByText("Loading review queue...")).toBeInTheDocument();
+	});
+
+	it("shows error with retry button", async () => {
+		const onRefresh = vi.fn();
+		render(
+			<ReviewPanel
+				{...baseProps}
+				reviewError="Network error"
+				onRefresh={onRefresh}
+			/>,
+		);
+
+		expect(
+			screen.getByText(/Network error.*Use Refresh to try again\./),
+		).toBeInTheDocument();
+
+		await userEvent.click(screen.getByRole("button", { name: "Retry" }));
+		expect(onRefresh).toHaveBeenCalledOnce();
+	});
+
+	it("renders ready story with Proceed button", () => {
+		render(<ReviewPanel {...baseProps} reviewQueue={[readyStory]} />);
+
+		expect(screen.getByText("29_backfill_tests")).toBeInTheDocument();
+		expect(screen.getByText("Ready")).toBeInTheDocument();
+		expect(screen.getByRole("button", { name: "Proceed" })).toBeEnabled();
+	});
+
+	it("renders blocked story with disabled button", () => {
+		render(<ReviewPanel {...baseProps} reviewQueue={[blockedStory]} />);
+
+		expect(screen.getByText("26_tdd_gates")).toBeInTheDocument();
+		expect(screen.getAllByText("Blocked")).toHaveLength(2);
+		expect(screen.getByRole("button", { name: "Blocked" })).toBeDisabled();
+	});
+
+	it("shows failing badge with count", () => {
+		render(<ReviewPanel {...baseProps} reviewQueue={[blockedStory]} />);
+		expect(screen.getByText("Failing 2")).toBeInTheDocument();
+	});
+
+	it("shows warning badge", () => {
+		render(<ReviewPanel {...baseProps} reviewQueue={[blockedStory]} />);
+		expect(screen.getByText("Warning")).toBeInTheDocument();
+	});
+
+	it("shows test summary per story", () => {
+		render(<ReviewPanel {...baseProps} reviewQueue={[readyStory]} />);
+		expect(screen.getByText(/5\/5 passing,\s*0 failing/)).toBeInTheDocument();
+	});
+
+	it("shows missing categories", () => {
+		const missingStory: ReviewStory = {
+			...blockedStory,
+			missing_categories: ["unit", "integration"],
+		};
+		render(<ReviewPanel {...baseProps} reviewQueue={[missingStory]} />);
+		expect(screen.getByText("Missing: unit, integration")).toBeInTheDocument();
+	});
+
+	it("calls onProceed when Proceed is clicked", async () => {
+		const onProceed = vi.fn().mockResolvedValue(undefined);
+		render(
+			<ReviewPanel
+				{...baseProps}
+				reviewQueue={[readyStory]}
+				onProceed={onProceed}
+			/>,
+		);
+
+		await userEvent.click(screen.getByRole("button", { name: "Proceed" }));
+		expect(onProceed).toHaveBeenCalledWith("29_backfill_tests");
+	});
+
+	it("shows queue counts in header", () => {
+		render(
+			<ReviewPanel {...baseProps} reviewQueue={[readyStory, blockedStory]} />,
+		);
+		expect(screen.getByText(/1 ready \/ 2 total/)).toBeInTheDocument();
+	});
+
+	it("shows proceedError message", () => {
+		render(
+			<ReviewPanel
+				{...baseProps}
+				proceedError="Acceptance blocked: tests failing"
+			/>,
+		);
+		expect(
+			screen.getByText("Acceptance blocked: tests failing"),
+		).toBeInTheDocument();
+	});
+
+	it("shows proceedSuccess message", () => {
+		render(
+			<ReviewPanel
+				{...baseProps}
+				proceedSuccess="Story accepted successfully"
+			/>,
+		);
+		expect(screen.getByText("Story accepted successfully")).toBeInTheDocument();
+	});
+
+	it("shows reasons as list items", () => {
+		render(<ReviewPanel {...baseProps} reviewQueue={[blockedStory]} />);
+		expect(screen.getByText("2 tests are failing.")).toBeInTheDocument();
+	});
+});