Optional test

[RobinTail]

Following the #4920 I'd like to share a code sample I found out recently for implementing an optional test that depends on external resource having questionable availability and uses the built-in skipping mechanism instead of just passing with a message that can be lost in logs. This may also be useful for flaky tests. The idea is to wrap the flaky part into the test.extend() and use the context-level skip() method inside the actual test.

describe("Optional test", () => {
  test.extend("response", async () => {
    try {
      return await fetch("https://...", {
        signal: AbortSignal.timeout(3000),
      });
    } catch { /* log actual error here if needed */ }
  })("the actual test", async ({ response, skip }) => {
    if (!response) return skip("resource is unreachable");
    await response.json(); // use the data in test
  });
});

I found this approach cleaner than async describe and test.skipIf().

The default reporter handles it nicely:

${\textsf{\color{green}✓}} {\textsf{Optional test}} {\textsf{\color{gray}(1)}}$
${\space \space \space \space}{\textsf{\color{gray}↓}} {\textsf{the actual test}} {\textsf{\color{yellow}3006ms}} {\textsf{\color{gray}[resource is unreachable]}}$

And the summary emphasizes the skipped test:

${\textsf{\color{gray}Tests}} \space \space {\textsf{\color{green}37 passed}} {\textsf{\color{gray}|}} {\textsf{\color{yellow}1 skipped}} {\textsf{\color{gray}(38)}}$

References:

• test.extend — https://vitest.dev/api/test.html#test-extend
• context.skip — https://vitest.dev/guide/test-context.html#skip