Test

Test handlers

Writing tests is very similar to writing handlers and library functions. The main difference is that the files are in the test/test folder, the first test being the layer name and the second test being part of the name of the handlers, which becomes xxx.test. The layer name is useful to activate tests only when needed, while the xxx.test is convenient way to find all test handlers and attach them to the orchestrator where they can run.

Each test must return an array of steps. Each step is a function or another array of steps. Test handlers receive two arguments: the first one is parameters for the test, the second one is $meta. The first parameter can optionally include the property name, to give a name to the test. This is useful when reusing test handlers and passing different parameters, so the test is reported in the output as different test names. The test name must be set as a property of the returned array. This is done by the rename function provided by the framework, which returns the passed array with the name property set. When the steps of the test are executed, the result of each step is set in an object called context. The name of the function determines the name of the property within the context, where the result is set. Tests start with a context, which is an empty object. Subsequent steps can access the context, so that values from previous tests can be passed to handlers and other tests. Test steps are called with two parameters: assert and context. By default the assert function is the one coming from node:assert, but it can be changed to other ones, like the ones coming from tap, which are mainly useful for snapshot testing with the matchSnapshot assertion function, which is not available in node:assert.

Example:

// realmname/test/test/testSomething.ts
import {IMeta, handler} from '@feasibleone/blong';
import type Assert from 'node:assert';

export default handler(({
    lib: {rename},
    handler: {
        testLoginTokenCreate,
        subjectObjectPredicate
    }
}) => ({
    testSomething: ({name = 'something'}, $meta) =>
        rename([
            testLoginTokenCreate({}, $meta), // reuse another test
            async function testCase(
                assert: typeof Assert,
                {$meta}: {$meta: IMeta}
            ) {
                const result = await subjectObjectPredicate<{data: string}>(
                    {},
                    $meta
                );
                assert.equal(result.data, 'expected data', 'Return expected data');
            }
        ], name)
}));