describe Nanoc::Telemetry::Summary do
  subject(:summary) { described_class.new }

  context 'no observations' do
    it 'errors on #min' do
      expect { subject.min }
        .to raise_error(Nanoc::Telemetry::Summary::EmptySummaryError)
    end

    it 'errors on #max' do
      expect { subject.max }
        .to raise_error(Nanoc::Telemetry::Summary::EmptySummaryError)
    end

    it 'errors on #avg' do
      expect { subject.avg }
        .to raise_error(Nanoc::Telemetry::Summary::EmptySummaryError)
    end

    it 'errors on #sum' do
      expect { subject.sum }
        .to raise_error(Nanoc::Telemetry::Summary::EmptySummaryError)
    end

    its(:count) { is_expected.to eq(0) }
  end

  context 'one observation' do
    before { subject.observe(2.1) }

    its(:count) { is_expected.to eq(1) }
    its(:sum) { is_expected.to eq(2.1) }
    its(:avg) { is_expected.to eq(2.1) }
    its(:min) { is_expected.to eq(2.1) }
    its(:max) { is_expected.to eq(2.1) }

    it 'has proper quantiles' do
      expect(subject.quantile(0.00)).to eq(2.1)
      expect(subject.quantile(0.25)).to eq(2.1)
      expect(subject.quantile(0.50)).to eq(2.1)
      expect(subject.quantile(0.90)).to eq(2.1)
      expect(subject.quantile(0.99)).to eq(2.1)
    end
  end

  context 'two observations' do
    before do
      subject.observe(2.1)
      subject.observe(4.1)
    end

    its(:count) { is_expected.to be_within(0.000001).of(2) }
    its(:sum) { is_expected.to be_within(0.000001).of(6.2) }
    its(:avg) { is_expected.to be_within(0.000001).of(3.1) }
    its(:min) { is_expected.to be_within(0.000001).of(2.1) }
    its(:max) { is_expected.to be_within(0.000001).of(4.1) }

    it 'has proper quantiles' do
      expect(subject.quantile(0.00)).to be_within(0.000001).of(2.1)
      expect(subject.quantile(0.25)).to be_within(0.000001).of(2.6)
      expect(subject.quantile(0.50)).to be_within(0.000001).of(3.1)
      expect(subject.quantile(0.90)).to be_within(0.000001).of(3.9)
      expect(subject.quantile(0.99)).to be_within(0.000001).of(4.08)
    end
  end
end