test: add coverage for useSolvers

src/hooks/useSolvers.test.ts

@@ -0,0 +1,87 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { renderHook, waitFor } from "@testing-library/react";
+import { SWRConfig } from "swr";
+import { createElement, type ReactNode } from "react";
+import { useSolvers } from "./useSolvers";
+import type { Solver } from "@/lib/types";
+
+const wrapper = ({ children }: { children: ReactNode }) =>
+  createElement(SWRConfig, { value: { provider: () => new Map(), dedupingInterval: 0 } }, children);
+
+describe("useSolvers", () => {
+  beforeEach(() => {
+    vi.stubGlobal("fetch", vi.fn());
+  });
+
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it("starts with an empty array while loading", () => {
+    (fetch as ReturnType<typeof vi.fn>).mockReturnValue(new Promise(() => {}));
+
+    const { result } = renderHook(() => useSolvers(), { wrapper });
+
+    expect(result.current.solvers).toEqual([]);
+    expect(result.current.isLoading).toBe(true);
+    expect(result.current.error).toBeUndefined();
+  });
+
+  it("populates once the request resolves", async () => {
+    const solvers: Solver[] = [
+      {
+        name: "Alpha",
+        address: "GABC123",
+        bondUsd: 10000,
+        fills: 42,
+        failed: 1,
+        volumeUsd: 500000,
+        avgFillTimeSeconds: 3.2,
+        successRatePct: 97.6,
+        chains: ["ethereum", "stellar"],
+        status: "active",
+      },
+    ];
+    (fetch as ReturnType<typeof vi.fn>).mockResolvedValue({
+      ok: true,
+      status: 200,
+      json: async () => solvers,
+    });
+
+    const { result } = renderHook(() => useSolvers(), { wrapper });
+    expect(result.current.solvers).toEqual([]);
+
+    await waitFor(() => expect(result.current.solvers).toEqual(solvers));
+    expect(result.current.isLoading).toBe(false);
+    expect(result.current.error).toBeUndefined();
+    expect(fetch).toHaveBeenCalledWith(expect.stringContaining("/solvers"), expect.anything());
+  });
+
+  it("resolves to an empty array when no solvers are returned", async () => {
+    (fetch as ReturnType<typeof vi.fn>).mockResolvedValue({
+      ok: true,
+      status: 200,
+      json: async () => [],
+    });
+
+    const { result } = renderHook(() => useSolvers(), { wrapper });
+
+    await waitFor(() => expect(result.current.isLoading).toBe(false));
+    expect(result.current.solvers).toEqual([]);
+    expect(result.current.error).toBeUndefined();
+  });
+
+  it("surfaces a fetch failure as an error", async () => {
+    (fetch as ReturnType<typeof vi.fn>).mockResolvedValue({
+      ok: false,
+      status: 500,
+      statusText: "Internal Server Error",
+      text: async () => "",
+    });
+
+    const { result } = renderHook(() => useSolvers(), { wrapper });
+
+    await waitFor(() => expect(result.current.error).toBeDefined());
+    expect(result.current.solvers).toEqual([]);
+  });
+});