Cryptography and SSL/TLS Toolkit

Testing Policy

This applies to all stable and development branches of the main code repository.

Within this policy functional behaviour means what the system does, i.e. given a set of inputs it will produce a set of outputs. This does not include how the system does it. For example refactoring or performance improvements do not affect functional behaviour.

Except where noted below:

  • All Pull Requests adding new functionality to the applications, libraries, providers or engines must include suitable tests.
  • All Pull Requests fixing a functional behaviour defect in the applications, libraries, providers or engines must include a test for that defect.

Pull Requests that do not change the functional behaviour of the applications, libraries, providers or engines do not require tests to be added. For example the following types of changes do not require tests:

  • Changes to comments, formatting, internal naming or similar
  • Fixes for performance
  • Refactoring

To be explicit the above statement means that tests are not required for changes in:

  • Documentation (including CHANGES/NEWS)
  • The test suite
  • perl utilities
  • Include files
  • Build system
  • Demos

Pull Requests that only affect minor cosmetic output do not require tests.

It is acceptable for the tests to be added via a different Pull Request to the main Pull Request.

A test may be omitted where writing the test would result in disproportionately more effort than writing the code being tested. For example, difficult to reproduce error conditions.

Triage Labels

Before approving a PR, the applicability of the testing policy to the PR must be assessed and an appropriate label applied to the PR. One of the following labels must be applied:

  • tests: present, to be added where suitable tests are included in the same PR.
  • hold: tests needed, where the testing policy requires tests but they are not currently included in a PR.
  • tests: exempted, where tests are not included in a PR but are not required by this policy (for example, because the PR concerns only documentation, or because writing the test would result in disproportionately more effort; see above).
  • tests: deferred, where the tests are required by the testing policy but it is intended to add these tests in a subsequent PR. The label should be removed (for example from a closed PR) once subsequent tests have been merged.

The hold: tests needed label blocks merging of the PR and constitutes a hold. None of the other labels listed above block merging of a PR.

Only one of the above labels should be set on a PR at a given time.

It will generally be readily apparent which label is applicable at any given time. However, if there is a lack of agreement over the status of a PR in regards to the test policy, this should be resolved via the normal review process. For example, OpenSSL Committers are not required to agree to use of the tests: deferred label if they do not feel it is appropriate.

Use and approval of the tests: deferred label is at the discretion of the OpenSSL Committers. It is recommended that this label be used only when a subsequent PR with tests is anticipated, but no specific rule is imposed on when tests: deferred may be used at this time. The intention is to begin surveillance and obtain visibility into how decisions under the testing policy are being made prior to making any more specific prescriptions. For example, this labelling allows obtaining a list of merged PRs for which a decision was made to defer adding tests, but for which tests have not yet been added.

Performance Testing

Performance testing should be performed automatically via CI on a regular basis for certain components as defined by the OTC.

Examples of performance testing that should be considered include:

  • Individual algorithm performance operating over different input sizes
  • SSL/TLS handshake time over multiple handshakes and for different protocol versions and resumption/non-resumption handshakes

Performance figures should be collected and tracked over time.


This section makes recommendations that are not mandatory but should be considered.

Pull requests that implement significant new functionality should consider whether fuzz tests should be added.

As per the policy wording above, pull requests that implement refactoring are not required to add new tests. However before refactoring is a good time to check that there are sufficient tests and that all corner cases are covered.

Where performance fixes are implemented consideration should be given to whether we need to add a performance test to the performance testing suite.