Create PQC Compliance Integration Test for Gaxios

[danieljbruce]

This PR introduces a robust Post-Quantum Cryptography (PQC) integration test for Gaxios. It verifies that standard HTTPS requests made with Gaxios successfully negotiate TLS connections using the hybrid post-quantum key exchange group X25519MLKEM768 when executed on a PQC-compliant Node.js runtime (v22.20+ and v24.7.0+).

Key elements implemented:

• Native in-memory HTTPS server using self-signed RSA certificates inside the test.
• Node.js Compatibility Guard: checking process version and performing a dry-run secure context initialization using 'X25519MLKEM768' to safely skip on unsupported systems.
• Custom https.Agent override to hook client-side TLSSocket generation, verifying correct protocol (TLSv1.3) and negotiation.
• Global Nock bypass specifically for localhost/127.0.0.1.

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PR created automatically by Jules for task 5397569580220749849 started by @danieljbruce

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[gemini-code-assist]

Code Review

This pull request formats type definitions and test files, and introduces a new integration test suite to verify Post-Quantum Cryptography (PQC) compliance using the hybrid curve X25519MLKEM768. The review feedback recommends simplifying the PQC support check by removing fragile Node.js version checks in favor of pure feature detection, and properly closing the test HTTPS server by terminating active connections and awaiting its closure to prevent potential test hangs.

[gemini-code-assist]

Relying on hardcoded Node.js version checks (like checking for specific major/minor versions) is fragile and can easily break or incorrectly skip tests on other supported runtimes (such as Node.js v23, custom builds, or future releases). Since you are already performing a robust feature detection check using tls.createSecureContext({ecdhCurve: 'X25519MLKEM768'}), you can completely remove the version parsing logic and rely solely on the feature check.

  before(function () {
    try {
      tls.createSecureContext({ecdhCurve: 'X25519MLKEM768'});
      isPQCSupported = true;
    } catch (e) {
      isPQCSupported = false;
    }

    if (!isPQCSupported) {
      console.log(
        'Skipping PQC Integration test on unsupported Node.js runtime version: ' + process.versions.node,
      );
      this.skip();
    }
  });

[gemini-code-assist]

The server.close() method is asynchronous and does not force-close active connections by default. If there are any active or keep-alive connections, the server will remain open, which can cause the test runner to hang or lead to "port in use" errors in subsequent tests. Since this test runs on Node.js v22+, you can use server.closeAllConnections() and await the server closure to ensure a clean teardown.

    } finally {
      if (typeof server.closeAllConnections === 'function') {
        server.closeAllConnections();
      }
      await new Promise<void>(resolve => server.close(() => resolve()));
    }