kurkar
v0.1.2
Published
Ava macros to test RxJS, with TypeScript support
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Kurkar: Ava macros to test RxJS
Kurkar helps you test RxJS operators and pipelines with marbles using Ava. Ava macros let you write concise tests.
Install
npm install --save-dev kurkar
Basic usage
import test from 'ava';
import marbles from 'kurkar';
test('observable', marbles, (_t, _sched, helpers) => {
const letters = 'the quick brown fox jumps over the lazy dog|';
const source$ = helpers.hot(letters);
helpers.expectObservable(source$).toBe(letters);
});
Kurkar provides an Ava test macro to easily set up RxJS
tests in Ava. Include the macro function marbles
before the test
function to hook up an RxJS TestScheduler
to the
Ava execution context "t
". The test function will be run inside a
test scheduler, with these parameters:
t
: Ava execution context for this test.sched
: RxJSTestScheduler
running this test. Use when you need to pass a scheduler argument into some operators.helpers
: Helper functions created byTestScheduler.run
for easily creating and comparing Observables.
TestScheduler
runs synchronously, so the test function is not
async
.
The marbles
macro uses t.deepEqual
to compare actual and expected
results. Pass a different comparison function to withEquals
to
generate other versions of the macro. marbles
is just
const marbles = withEquals((t, a, e) => t.deepEqual(a, e));
TypeScript support
Kurkar fully supports TypeScript types and exports useful types. You
do not need to install additional @types
to enjoy TypeScript.
Here's a typed version of the above test:
import test from 'ava';
import marbles, { withEquals, ExecutionContext, TestScheduler, RunHelpers } from 'kurkar';
test('observable', marbles, (_t: ExecutionContext, _sched: TestScheduler, helpers: RunHelpers) => {
const letters = 'the quick brown fox jumps over the lazy dog|';
const source$ = helpers.hot(letters);
helpers.expectObservable(source$).toBe(letters);
});
Due to current limitations with Ava types, TypeScript language servers currently cannot always deduce the types of the test function parameters.
FAQ
Why another Ava RxJS marbles library?
Because it provides an Ava test macro, Kurkar removes the most boilerplate from your tests. It is native TypeScript and can provide exact type-checking.
Why the name?
"Kurkar" ("כורכר") is a soft middle-eastern sandstone -- a very different rock from marble.