title: "OPAM 1.2 and Travis CI" authors: "Thomas Gazagnaire" {"http://gazagnaire.org"} date: "2014-12-18" --BODY--
The new pinning feature of OPAM 1.2 enables new interesting workflows for your day-to-day development in OCaml projects. I will briefly describe one of them here: simplifying continuous testing with Travis CI and GitHub.
As explained in the previous post, adding an opam
file at the
root of your project now lets you pin development versions of your
project directly. It's very easy to create a default template with OPAM 1.2:
$ opam pin add <my-project-name> . --edit
[... follow the instructions ...]
That command should create a fresh opam
file; if not, you might
need to fix the warnings in the file by re-running the command. Once
the file is created, you can edit it directly and use opam lint
to
check that is is well-formed.
If you want to run tests, you can also mark test-only dependencies with the
{test}
constraint, and add a build-test
field. For instance, if you use
oasis
and ounit
, you can use something like:
build: [
["./configure" "--prefix=%{prefix}%" "--%{ounit:enable}%-tests"]
[make]
]
build-test: [make "test"]
depends: [
...
"ounit" {test}
...
]
Without the build-test
field, the continuous integration scripts
will just test the compilation of your project for various OCaml
compilers.
OPAM doesn't run tests by default, but you can make it do so by
using opam install -t
or setting the OPAMBUILDTEST
environment variable in your local setup.
Travis CI is a free service that enables continuous testing on your GitHub projects. It uses Ubuntu containers and runs the tests for at most 50 minutes per test run.
To use Travis CI with your OCaml project, you can follow the instructions on https://github.com/ocaml/ocaml-travisci-skeleton. Basically, this involves:
- adding
.travis.yml
at the root of your project. You can tweak this file to test your
project with different versions of OCaml. By default, it will use
the latest stable version (today: 4.02.1, but it will be updated for
each new compiler release). For every OCaml version that you want to
test (supported values for
<VERSION>
are3.12
,4.00
,4.01
and4.02
) add the line:
env:
- OCAML_VERSION=<VERSION>
- signing in at TravisCI using your GitHub account and
enabling the tests for your project (click on the
+
button on the left pane).
And that's it, your project now has continuous integration, using the OPAM 1.2 pinning feature and Travis CI scripts.
By default, the script will not try to install the optional
dependencies specified in your opam
file. To do so, you
need to manually specify which combination of optional dependencies
you want to tests using the DEPOPTS
environment variable. For
instance, to test cohttp
first with lwt
, then with async
and
finally with both lwt
and async
(but only on the 4.01
compiler)
you should write:
env:
- OCAML_VERSION=latest DEPOPTS=lwt
- OCAML_VERSION=latest DEPOPTS=async
- OCAML_VERSION=4.01 DEPOPTS="lwt async"
As usual, your contributions and feedback on this new feature are gladly welcome.