Run Smoke Tests

Run smoke tests to verify the extension loads and basic functionality works in a real VS Code environment.

When to Use This Skill

• After making changes to extension activation code
• After modifying commands or API exports
• Before submitting a PR to verify nothing is broken
• When the user asks to "run smoke tests" or "verify the extension works"

Quick Reference

| Action | Command |

| ------------------- | ---------------------------------------------------------------- |

| Run all smoke tests | npm run compile && npm run compile-tests && npm run smoke-test |

| Run specific test | npm run smoke-test -- --grep "Extension activates" |

| Debug in VS Code | Debug panel → "Smoke Tests" → F5 |

How Smoke Tests Work

Unlike unit tests (which mock VS Code), smoke tests run inside a real VS Code instance:

• npm run smoke-test uses @vscode/test-cli
• The CLI downloads a standalone VS Code binary (cached in .vscode-test/)
• It launches that VS Code with your extension installed
• Mocha runs test files inside that VS Code process
• Results are reported back to your terminal

This is why smoke tests are slower (~10-60s) but catch real integration issues.

Workflow

Step 1: Compile and Run

npm run compile && npm run compile-tests && npm run smoke-test

Step 2: Interpret Results

Pass: 4 passing (2s) → Extension works, proceed.

Fail: See error message and check Debugging section.

Running Individual Tests

To run a specific test instead of the whole suite:

# By test name (grep pattern)
npm run smoke-test -- --grep "Extension activates"

# Or temporarily add .only in code:
test.only('Extension activates without errors', ...)

Debugging Failures

| Error | Cause | Fix |

| --------------------------------- | ----------------------------- | ------------------------------------------- |

| Extension not installed | Build failed or ID mismatch | Run npm run compile, check extension ID |

| Extension did not become active | Error in activate() | Debug with F5, check Debug Console |

| Command not registered | Missing from package.json | Add to contributes.commands |

| Timeout exceeded | Slow startup or infinite loop | Increase timeout or check for blocking code |

For detailed debugging, use VS Code: Debug panel → "Smoke Tests" → F5

Adding New Smoke Tests

Create a new file in src/test/smoke/ with the naming convention *.smoke.test.ts:

import * as assert from 'assert';
import * as vscode from 'vscode';
import { waitForCondition } from '../testUtils';
import { ENVS_EXTENSION_ID } from '../constants';

suite('Smoke: [Feature Name]', function () {
    this.timeout(60_000);

    test('[Test description]', async function () {
        // Arrange
        const extension = vscode.extensions.getExtension(ENVS_EXTENSION_ID);
        assert.ok(extension, 'Extension not found');

        // Ensure extension is active
        if (!extension.isActive) {
            await extension.activate();
        }

        // Act
        const result = await someOperation();

        // Assert
        assert.strictEqual(result, expected, 'Description of what went wrong');
    });
});

Key patterns:

• Use waitForCondition() instead of sleep() for async assertions
• Set generous timeouts (this.timeout(60_000))
• Include clear error messages in assertions

Test Files

| File | Purpose |

| ----------------------------------------- | ---------------------------------- |

| src/test/smoke/activation.smoke.test.ts | Extension activation tests |

| src/test/smoke/index.ts | Test runner entry point |

| src/test/testUtils.ts | Utilities (waitForCondition, etc.) |

Prerequisites

• CI needs webpack build: The extension must be built with npm run compile (webpack) before tests run. The test runner uses dist/extension.js which is only created by webpack, not by npm run compile-tests (tsc)
• Extension builds: Run npm run compile before tests

Notes

• First run downloads VS Code (~100MB, cached in .vscode-test/)
• Tests auto-retry once on failure