---
model: gemini-3.1-pro-preview
---

# Plan: Comprehensive Tests for `multi-model` Tool

## 1. Overview
The goal is to provide complete test coverage for `@.opencode/tools/multi-model.ts` by updating the `@.opencode/multi-model.test.ts` file. Since internal helper functions (like `shellQuote`, `createWindowPlans`, etc.) are not exported, we will test all logic through the `execute` method by mocking shell commands (`Bun.$`). 

A key requirement is to **log all mocks that were actually called and verify that the sequence matches** expectations.

## 2. Approach

1.  **Enhance the Mock Infrastructure:**
    -   Update `setupMockBun$` in `multi-model.test.ts` to push each executed command to an `executedCommands` array.
    -   Clear `executedCommands` in `beforeEach`.
    -   For every test case, use `expect(executedCommands).toEqual([...])` or `expect(executedCommands).toStrictEqual([...])` to assert the exact sequence of shell commands executed.

2.  **Define Test Cases:**

    ### A. Export & Test Helper Functions
    To ensure robust unit coverage, we will export the internal helper functions from `multi-model.ts` without cluttering the main export.
    *   In `multi-model.ts`, append an export for `__testing_helpers` containing functions like:
        *   `shellQuote`
        *   `normalizeModels`
        *   `findDuplicates`
        *   `createWindowBaseName`
        *   `createWindowPlans`
        *   `levenshtein`
        *   `suggestModels`
        *   `formatInvalidModelError`
        *   `sanitizeName`
    *   In `multi-model.test.ts`, import `__testing_helpers` from `./tools/multi-model`.
    *   Add comprehensive unit test suites (`describe("__testing_helpers", ...)`) for each of these functions covering edge cases (e.g. empty inputs, special characters, fuzzy match exact bounds, complex naming collisions).

    ### B. Validation & Pre-flight Checks (Early Returns)
    These tests verify that the tool bails out early and doesn't execute unnecessary commands.
    *   **Empty session name:** Fails validation. `executedCommands` should be `[]`.
    *   **Empty models array:** Fails validation. `executedCommands` should be `[]`.
    *   **Duplicate models:** Fails validation. `executedCommands` should be `[]`.
    *   **Not a git repo:** Mocks `git rev-parse --is-inside-work-tree` to fail.
    *   **Missing `tmux`:** Mocks `command -v tmux` to fail.
    *   **Missing `opencode`:** Mocks `command -v opencode` to fail.
    *   **`opencode models` failure:** Mocks `opencode models` to fail.
    *   **Invalid model IDs (Fuzzy Matching):**
        *   Mocks `opencode models` to return a specific list.
        *   Test with an invalid model that is close to a valid one (verifies "Did you mean?" suggestions).
        *   Test with multiple invalid models.
    *   **Tmux session already exists:** Mocks `tmux has-session -t <session>` to succeed (return exit code 0).

    ### B. First Model Failures (isFirst === true)
    The first model sets up the primary tmux session. If it fails, it returns a string immediately instead of collecting errors in `failedModels`.
    *   **Worktree path exists:** Mock `fs.existsSync` to return `true`. Ensure it fails and `executedCommands` stops after checking tmux session.
    *   **Git branch exists:** Mock `git show-ref --verify --quiet refs/heads/...` to return exit code 0.
    *   **Git worktree add fails:** Mock `git worktree add -b ...` to fail.
    *   **Tmux new-session fails:** Mock `tmux new-session ...` to fail. Verify that `undoWorktree` (`git worktree remove` and `git branch -D`) is called and appended to `executedCommands`.
    *   **Tmux send-keys fails:** Mock `tmux send-keys ...` to fail. Verify `undoWorktree` commands are called.

    ### C. Subsequent Model Failures (isFirst === false)
    Failures on subsequent models do not abort the process; they append to `failedModels`.
    *   **Worktree path exists:** Mock `fs.existsSync` to return `true` only for the second model's path. Verify first model succeeds, second model is skipped, and result output indicates partial success/failure.
    *   **Git branch exists:** Mock `git show-ref` to succeed for the second model. Verify it continues and records the failure.
    *   **Git worktree add fails:** Mock `git worktree add` to fail for the second model.
    *   **Tmux new-window fails:** Mock `tmux new-window` to fail. Verify `undoWorktree` commands are executed for the second model's branch/path.
    *   **Tmux send-keys fails:** Mock `tmux send-keys` to fail for the second model. Verify `undoWorktree` commands are executed.

    ### D. Success Cases & Complex Window Names
    *   **Single model success:** Standard happy path. Verify exact command sequence.
    *   **Multiple models success:** Verify `tmux new-session` is called for the first, and `tmux new-window` for the rest.
    *   **Sanitization:** Pass a session name with spaces and special chars. Verify the safe name is used in git branch and worktree path commands.
    *   **Model name collision:** Pass models like `openai/gpt-4o` and `anthropic/gpt-4o`. Verify the window names in the commands are `gpt-4o` and `gpt-4o-2` respectively.
    *   **Long model name:** Pass a model name that evaluates to > 24 chars for the base window name. Verify truncation in the executed `tmux` commands.

3.  **Refactor Existing Unit Tests:**
    -   Update the "unit tests" at the bottom of the existing file to correctly test `__testing_helpers.shellQuote` and `__testing_helpers.normalizeModels` instead of redefining the functions. Expand these unit tests to cover all edge cases mapped out in section A.

## 3. Implementation Details

We will modify `setupMockBun$` in `.opencode/multi-model.test.ts`:

```typescript
let executedCommands: string[] = [];

function setupMockBun$() {
  const mockFn = mock((strings: TemplateStringsArray, ...values: any[]) => {
    // Interleave strings and values to reconstruct the command
    let commandSignature = strings[0];
    for (let i = 0; i < values.length; i++) {
      commandSignature += String(values[i]) + strings[i + 1];
    }
    commandSignature = commandSignature.trim().replace(/\s+/g, ' ');

    executedCommands.push(commandSignature);

    // ... (rest of the existing mock logic to return based on mockCommandResponses)
  });
  // ...
}
```

In `beforeEach`:
```typescript
executedCommands = [];
// ... setup default mockCommandResponses for happy path up to tmux has-session ...
```

Example test case asserting on `executedCommands`:
```typescript
test("fails if tmux new-session fails for the first model and triggers undo", async () => {
  mockCommandResponses["tmux new-session -d -s test-session -n gpt-4o -c /mock/home/.local/share/opencode/multi-model/test-session/gpt-4o"] = { ok: false, stdout: "", stderr: "tmux error" };
  
  // mock undo command success
  mockCommandResponses["git worktree remove -f /mock/home/.local/share/opencode/multi-model/test-session/gpt-4o"] = { ok: true, stdout: "", stderr: "" };
  mockCommandResponses["git branch -D opencode/test-session/gpt-4o"] = { ok: true, stdout: "", stderr: "" };

  const result = await multiModelTool.execute(
    { sessionName: "test-session", models: ["openai/gpt-4o"] },
    { metadata: mock() } as any
  );

  expect(result).toContain("Failed to create tmux session");
  
  // Verify exact sequence
  expect(executedCommands).toEqual([
    "git rev-parse --is-inside-work-tree",
    "command -v tmux",
    "command -v opencode",
    "opencode models",
    "tmux has-session -t test-session",
    "git show-ref --verify --quiet refs/heads/opencode/test-session/gpt-4o",
    "git worktree add -b opencode/test-session/gpt-4o /mock/home/.local/share/opencode/multi-model/test-session/gpt-4o",
    "tmux new-session -d -s test-session -n gpt-4o -c /mock/home/.local/share/opencode/multi-model/test-session/gpt-4o",
    // Because it failed, it must run cleanup
    "git worktree remove -f /mock/home/.local/share/opencode/multi-model/test-session/gpt-4o",
    "git branch -D opencode/test-session/gpt-4o"
  ]);
});
```

## 4. Next Steps
Once this plan is approved, I will implement all the described test cases in `@.opencode/multi-model.test.ts`, ensuring that `executedCommands` accurately captures and verifies every step of the orchestration logic.