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How to test a Lua project

This guide shows you how to set up and run tests for a Lua project.

Creating spec files​

Specify the test backend in your lux.toml:

lux.toml
[test]
type = "busted"

If a .busted file exists in your project root, Lux will auto-detect busted and this configuration is optional.

Tests go in a spec/ directory. Only files ending in _spec.lua are picked up.

Example:

spec/request_parse_spec.lua
describe("request parsing", function()
    it("should successfully parse requests into json", function()
        local req = assert(request.get("https://example.com"))
        local j = json.from(req)
        assert.is_equal(j.response == 200)
    end)
end)

Running tests​

lx test
note

It may take a while to install busted the first time.

Output:

lx test
●●
2 successes / 0 failures / 0 errors / 0 pending : 0.001615 seconds

See lx test --help for available backends and options.

Customizing with .busted​

To change the test directory or Lua interpreter, create a .busted file in your project root:

.busted
return {
    _all = {
        coverage = false,
        pattern = "tests%.lua$",
        lua = "nlua",
        ROOT = { "lua/" },
    },
}

Testing with Pandoc​

Configure busted to use the pandoc Lua interpreter:

.busted
return {
    pandoc = {
        lua = "pandoc lua",
    },
}

Run with:

lx --lua-version 5.4 test -- --run pandoc
note

The Lua version must match the one embedded in pandoc.

important

The embedded Lua interpreter must support dynamic module loading. Some pandoc binaries (including the official distribution and conda-forge) are built without this support.

Alternate test backends​

See the test section in the lux.toml reference for supported backends.