# The Tezos blockchain

This directory contains the sources of the Tezt framework. Tezt is a
generic test framework that is used for writing tests in OCaml for
Tezos.

## Overview

Information about Tezt and its documentation can be found online at
https://tezos.gitlab.io/developer/tezt.html

The Tezt directory contains several directories:

- `lib` defines an OCaml library named `tezt` which contains the test
  framework. It is independent from Tezos.

- `lib_tezos` defines another OCaml library named `tezt-tezos` which
  is specific to Tezos, complementing the above with Tezos-specific
  features.

- `tests` defines an OCaml executable which gathers automatic tests
  written for Tezos.

- `manual_tests` defines an OCaml executable which gathers manual
  tests written for Tezos. A manual test is a test which requires
  extra configuration and cannot be set up easily in the CI.

- `_regressions` defines a set of output expected from a call to an
  RPC or from some OCaml value serialized to JSON. If a file
  is added into this repository, it should be also added in the
  regression test which can be either `tests/RPC_test.ml` or
  `tests/encoding.ml`.

- `records` contains records of the time taken by tests, and a script that updates them.
  Records are used by the CI to distribute tests in jobs of roughly equal duration.
  To update it, get a recent CI pipeline ID and run (from the root of the Tezos repository):

    PIPELINE=<PIPELINE_ID> dune exec tezt/records/update.exe -- -i
    git add tezt/records
    git commit -m 'Tezt: update records'

## Implementation Details

Tezt is implemented in the [OCaml
language](https://ocaml.org). Currently, the project ensures that both
libraries `tezt` and `tezt-tezos` do not depend on any library of
`Tezos`. The motto of the library is to provide an **extensive** but
**simple** test framework for Tezos.

An important feature of `tezt` is the possibility to catch `events`
emitted by the node. This allows fine-grained tests. In particular, as
much as possible, a test in `tezt` should avoid the use of `timeouts`
and instead, should rely on `events` if possible.

Tezt provides an experimental module to deploy tests on remote machines.
It is important to note that it relies on the existence of an `openssh`
configuration on the different machines.

## API Documentation

The `tezt` and `tezt-tezos` APIs are documented in the
interface files (end by `mli`). Both APIs are available online:
https://tezos.gitlab.io/api/api-inline.html

The user manual of `tezt` is also available online on the [tezt
page](https://tezos.gitlab.io/developer/tezt.html).