require 'ganymed/sampler/derive'
require 'sampler/datasource_examples'

describe Ganymed::Sampler::Derive do
  include_context 'DataSource'
  subject { Ganymed::Sampler::Derive.new(ticks) }

  let(:ts) { now = Time.now.utc; now.to_i + (now.usec * 1e-6) }
  let(:values) { 10.times.collect { rand } }

  it_behaves_like Ganymed::Sampler::DataSource

  describe "#flush" do
    before(:each) do
      values.each do |value|
        subject.feed(ns, origin, ts, value)
      end
    end

    it "should call each" do
      subject.should_receive(:each).with(1).once
      subject.flush(1)
    end

    it "should yield derived values"
  end

  describe "#feed" do
    it "should add fed samples" do
      subject.should_receive(:add).with(ns, origin, [ts, value])
      subject.feed(ns, origin, ts, value)
    end
  end
end