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Balerter allows you to write tests for your scripts!

For that you can use core module test. Run tests you can with balerter/test tool and same configuration file as main.

Scrips will be obtained from scripts source, described in the configuration file. But all requests to datasources, or any core modules (as 'alert', 'kv' etc) will be mocked

writing tests

The main concept: One test script (with one or more test functions) for one main script

An example:

Main script:

-- @name demoscript

log = require('log')

-- log.warn('baz')

Now, write and discuss a test script:

-- @name demoscript-test
-- @test demoscript

local function my_test(test)
    test.log().on('error', 'foo').response()
    test.log().on('info', 'bar').response()

    test.log().assertCalled('error', 'foo')
    test.log().assertCalled('info', 'bar')
    test.log().assertNotCalled('warn', 'baz')

return {
    ['My Test'] = my_test,

With @test we did two things:

  1. Defined that this file is a test.
  2. Defined, that this test work with script with name 'demoscript'

You can to define multiply test functions. The test function has one parameter - test module.

At the end of the test script you must return a table with test names as keys and test functions as values

test module


A module test can be used only in test functions in scripts, which marked as tests with a tag @test

You can:

  • define data, which should be returned for calls to datasources or core modules in main script. If in the main script you wrote log.error('foo'), but in the test script you not define return value, you will get test error.
  • define Asserts for calls, which you want or not

Module methods:


test.<MODULE>.on(<METHOD>, [<ARG>, <ARG>, ...]).response([<ARG>, <ARG>, ...])


test.<MODULE>.assertCalled(<METHOD>, [<ARG>, <ARG>, ...])


test.<MODULE>.assertNotCalled(<METHOD>, [<ARG>, <ARG>, ...])

<MODULE> - it is may be datasource(<DATASOURCE_NAME>) for datasources. For example test.datasource('').

Or call core modules:

  • log()
  • http()
  • chart()
  • alert()
  • kv()

For example:

-- define a response ('nil' at now) for call `log.error('error message')` in a main script
test.log().on('error', 'error message').response()

-- check, that we want to see call `alert.error('alert-id', 'alert message')`
test.alert().assertCalled('error', 'alert-id', 'alert message')

-- define response for a call ch1.query('SELECT * FROM users'), ch1 = require('datasource.clickhouse.ch1')
test.datasource('clickhouse.ch1').on('query', 'SELECT * FROM users').response({ { id = 1, name = 'John' } })

Important! Even you call returns nothing (, you should register this call with test.log().on('info', 'message').response()

run tests

You can use the tool test

Docker image example:

docker run --rm \
    -v /path/to/config.hcl:/opt/config.hcl \
    -v /path/to/scripts:/opt/scripts \
    balerter/test -config=/opt/config.hcl

If run fails, exit code will be equal 1. If run was success, but tests fails, exit code will be equals 2.

An output example:

[PASS]  [demo-test]     [test name 1]   [alert] method 'success' with args [alert-id,All OK] was called
[PASS]  [demo-test]     [test name 1]   [kv]    method 'get' with args [foo] was called
[PASS]  [demo-test]     [test name 1]   PASS
[FAIL]  [demo-test]     [test name 2]   [alert] method 'success' with args [alert-id,All OK] was called, but should not
[PASS]  [demo-test]     [test name 2]   [alert] method 'error' with args [alert-id Error get key] was not called
[PASS]  [demo-test]     [test name 2]   [kv]    method 'get' with args [foo] was called
[FAIL]  [demo-test]     [test name 2]   FAIL
[FAIL]  [demo-test]     FAIL

First column - line result. Second column - a test script name. Third - test function name. Fourth - a module name. Last - a message. Last line mean total result for the script

Scripts from the example above:

-- main script
-- @name demo

alert = require('alert')
kv = require('kv')

v, err = kv.get('foo')

if err ~= nil then
    alert.error('alert-id', 'Error get key')
    alert.success('alert-id', 'All OK')
-- test script
-- @test demo
-- @name demo-test

local function test1(test)
    test.alert().on('success', 'alert-id', 'All OK').response()
    test.alert().assertCalled('success', 'alert-id', 'All OK')

    test.kv().on('get', 'foo').response(42, nil)
    test.kv().assertCalled('get', 'foo')

local function test2(test)
    test.alert().on('success', 'alert-id', 'All OK').response()
    test.alert().assertNotCalled('success', 'alert-id', 'All OK')
    test.alert().assertNotCalled('error', 'alert-id', 'Error get key')

    test.kv().on('get', 'foo').response(42, nil)
    test.kv().assertCalled('get', 'foo')

return {
    ['test name 1'] = test1,
    ['test name 2'] = test2,