Client Testing Strategy: Lite Unit and Integration

Client testing gets expensive fast when the test layers are wrong.

If you make every test talk to a live network, your feedback loop becomes slow and flaky.

If you only test pure helpers, your UI and wallet flows break in ways the test suite never sees.

The right model is layered.

Test three things separately:

• pure client logic
• UI behavior around hooks and statuses
• one real integration path that proves the stack works together

That is enough for most serious frontend work.

Start With Pure Logic

Pure logic is the cheapest place to catch mistakes.

Examples from this section:

• classifyTxError(...)
• getRecoveryHint(...)
• token transfer input validation
• address normalization helpers

These functions do not need a wallet.

They do not need RPC.

They should be tested first.

Step 1: Unit Test The Logic That Drives UX Decisions

Install the test stack if needed:

pnpm add -D vitest @testing-library/react @testing-library/jest-dom jsdom

Now create lib/solana/__tests__/uiTxState.test.ts:

import { describe, expect, it } from "vitest";
import { classifyTxError, getRecoveryHint } from "../uiTxState";

describe("uiTxState", () => {
  it("maps user rejection", () => {
    expect(classifyTxError("User rejected request")).toBe("user-rejected");
  });

  it("maps blockhash expiry", () => {
    expect(classifyTxError("Blockhash not found")).toBe("expired");
  });

  it("returns a recovery hint for program errors", () => {
    expect(getRecoveryHint("program")).toMatch(/inputs/i);
  });
});

This is the kind of test that should run constantly.

It is fast.

It is deterministic.

And it directly protects the user-facing behavior of your app.

Step 2: Test UI Behavior With Mocked Hook State

The official React hooks docs explicitly call out two useful testing patterns:

• mock hook return values directly
• pass a mocked client into SolanaProvider

For most UI components, mocking hook return values is the fastest path.

Create components/solana/__tests__/WalletPanel.test.tsx:

import { describe, expect, it, vi } from "vitest";
import { render, screen } from "@testing-library/react";
import { WalletPanel } from "../WalletPanel";

vi.mock("@solana/react-hooks", () => ({
  useWalletConnection: () => ({
    connectors: [{ id: "phantom", name: "Phantom" }],
    wallet: null,
    status: "disconnected",
    connect: vi.fn(),
    disconnect: vi.fn(),
  }),
}));

describe("WalletPanel", () => {
  it("renders available connectors when disconnected", () => {
    render(<WalletPanel />);
    expect(screen.getByText(/Choose wallet/i)).toBeTruthy();
    expect(screen.getByText(/Connect Phantom/i)).toBeTruthy();
  });
});

This test is still cheap.

But it protects a real UI contract.

If the component stops showing available connectors correctly, the test catches it.

Step 3: Keep One Real Integration Path

After unit tests and UI tests, keep one integration path that proves your client stack still works together.

That path should be small and meaningful.

For this module, a good candidate is:

• connect wallet in app state
• build one SOL transfer instruction
• send it through the shared transport
• assert a real signature comes back

That is enough.

You do not need ten end-to-end tests to trust the client.

You need one honest path that exercises the real runtime.

A Practical Rule For This Section

Use this split:

• unit tests for logic helpers
• component tests for status and rendering behavior
• one integration flow for wallet + transport + signature outcome

That gives you speed without losing realism.

The Failure Modes To Avoid

Testing only happy paths

Solana clients fail in normal ways:

• user rejection
• disconnected wallet
• expired lifetime
• invalid program input

If those are untested, the suite is weak.

Making every test hit the network

That turns the suite into a latency benchmark.

Keep most tests local and deterministic.

Letting UI tests depend on a real browser wallet

Mock the hook state or pass a mocked client.

Do not make simple component tests depend on wallet extensions.

What You Can Do After This

You can design a test suite that protects the real failure modes in a Solana client without making every test expensive or flaky.

That is the correct testing posture for a modern kit-first frontend.

Quick Check

Sources

• https://solana.com/docs/frontend/react-hooks
• https://solana.com/docs/frontend/client
• https://vitest.dev/