bittrance/rx-rspec

# Rspec matchers for RxRuby observables

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## Rationale

The asynchronous nature of RxRuby makes it hard to write good specs for code that returns observables. The complexity of next/error/completed notifications can also easily trip up a naive spec.

## Goal

The goal of rx-rspec is to provide powerful matchers that lets you express your expectations in a traditional rspec-like synchronous manner.

Currently, the ambition of this project is simply to support the use cases that I encounter in my own usage of RxRuby. Your pull requests are welcome.

## Usage

rx-rspec is available from http://rubygems.org:
```
gem install rx-rspec
```

Once installed, you can use it to assert on your observables:
```
require 'rx'
require 'rx-rspec'

describe 'awesome' do
  subject { Rx::Observable.of(1, 2, 3) }
  it { should emit_exactly(1, 2, 3) }
end
```
You can also set a timeout in seconds so your specs don't block forever in case an observable never emits/completes/errors.
```
it 'should be fast' do
  expect(observable).to emit_exactly(42).within(0.1)
end
```

## Matchers

rx-spec include the following matchers:

- **emit_error(class, message)** matches an observable that errors without emitting any values.
- **emit_exactly(\*events)** matches an observable that emits exactly the given values and requires the observable to be completed.
- **emit_first(\*events)** matches against the first values emitted by the observable, but does not require it to complete.
- **emit_include(\*events)** consumes values until the expected values have been seen.
- **emit_nothing()** matches an observable that completes without emitting values or erroring.