require 'spec_helper'

describe HealthReporter do
  subject { HealthReporter }

  it 'has a version number' do
    expect(HealthReporter::VERSION).not_to be nil
  end

  before(:each) do
    subject.healthy_cache_ttl = 60
    subject.unhealthy_cache_ttl = 30
    subject.self_test = lambda{ true }
    subject.class_variable_set(:@@last_check_time, nil)
    subject.class_variable_set(:@@healthy, nil)
    Timecop.return
    reset_lambda_runner_spy
  end

  context 'when configuring' do
    it 'remembers the self-test lambda passed to it' do
      test_lambda = lambda{ 'ab' == 'cd' }
      subject.self_test = test_lambda
      expect(subject.self_test).to be test_lambda
    end

    it 'uses the self-test lambda passed to it' do
      test_lambda = spy_lambda_returning_false
      subject.self_test = test_lambda
      expect(subject.self_test).to be test_lambda
      expect(subject.healthy?).to be false
      expect(spy_lambda_was_run?).to eq true
    end

    it 'remembers the cache ttl when healthy' do
      subject.healthy_cache_ttl = 10
      expect(subject.healthy_cache_ttl).to eq 10
    end

    it 'remembers the cache ttl when not healthy' do
      subject.unhealthy_cache_ttl = 5
      expect(subject.unhealthy_cache_ttl).to eq 5
    end
  end

  context 'when exercising self-test lambda' do
    it 'allows true to be returned by self-test lambda' do
      test_lambda = lambda{ true }
      subject.self_test = test_lambda
      expect(subject.healthy?).to be true
    end

    it 'allows false to be returned by self-test lambda' do
      test_lambda = lambda{ false }
      subject.self_test = test_lambda
      expect(subject.healthy?).to be false
    end

    it 'raises an exception when non-boolean values are returned by self-test lambda' do
      test_lambda = lambda{ "I don't feel well..." }
      subject.self_test = test_lambda
      expect{subject.healthy?}.to raise_error RuntimeError, "Invalid non-boolean response from registered self-check lambda: I don't feel well..."
    end
  end

  context 'when initialized without any parameters' do
    it 'sets the default self-test lambda to { true }' do
      expect(subject.healthy?).to eq true
    end

    it 'sets the default healthy state cache ttl to 60 seconds' do
      expect(subject.healthy_cache_ttl).to eq 60
    end

    it 'sets the default unhealthy state cache ttl to 30 seconds' do
      expect(subject.unhealthy_cache_ttl).to eq 30
    end
  end

  context 'when calling health check for first time (no cached health state)' do
    it 'calls the configured self-test lambda and returns health' do
      subject.self_test = spy_lambda_returning_false
      expect(subject.healthy?).to be false
      expect(spy_lambda_was_run?).to eq true
    end
  end

  context 'when current state is healty' do
    before(:each) do
      subject.self_test = spy_lambda_returning_true
      subject.healthy? #force the self-test
      reset_lambda_runner_spy #reset the spy so that we can see if it was run or not
    end

    context 'when neither healty-cache-ttl nor unhealty-cache-ttl has expired' do
      before(:each) do
        subject.unhealthy_cache_ttl = 10
        subject.healthy_cache_ttl   = 10
        Timecop.freeze(Time.now + 5)
      end

      it 'does not call the registered self-test lambda' do
        subject.healthy? #request here and test if it was run in expect below
        expect(spy_lambda_was_run?).to eq false
      end
      it 'returns the current healthy state' do
        expect(subject.healthy?).to be true
      end
    end

    context 'when healty-cache-ttl has expired' do
      before do
        subject.unhealthy_cache_ttl = 10
        subject.healthy_cache_ttl   =  3
        Timecop.freeze(Time.now + 5)
      end

      it 'calls the registered self-test lambda' do
        subject.healthy? #request here and test if it was run in expect below
        expect(spy_lambda_was_run?).to eq true
      end
      it 'returns the current healthy state' do
        expect(subject.healthy?).to be true
      end
    end

    context 'when unhealty-cache-ttl has expired' do
      before(:each) do
        subject.unhealthy_cache_ttl =  3
        subject.healthy_cache_ttl   = 10
        Timecop.freeze(Time.now + 5)
      end

      it 'does not call the registered self-test lambda' do
        subject.healthy? #request here and test if it was run in expect below
        expect(spy_lambda_was_run?).to eq false
      end
      it 'returns the current healthy state' do
        expect(subject.healthy?).to be true
      end
    end
  end

  context 'when current state is unhealty' do
    before(:each) do
      subject.self_test = spy_lambda_returning_false
      subject.healthy? #force the self-test
      reset_lambda_runner_spy #reset the spy so that we can see if it was run or not
    end

    context 'when neither healty-cache-ttl nor unhealty-cache-ttl has expired' do
      before(:each) do
        subject.unhealthy_cache_ttl = 10
        subject.healthy_cache_ttl   = 10
        Timecop.freeze(Time.now + 5)
      end

      it 'does not call the registered self-test lambda' do
        subject.healthy? #request here and test if it was run in expect below
        expect(spy_lambda_was_run?).to eq false
      end
      it 'returns the current unhealthy state' do
        expect(subject.healthy?).to be false
      end
    end

    context 'when healty-cache-ttl has expired' do
      before(:each) do
        subject.unhealthy_cache_ttl = 10
        subject.healthy_cache_ttl   =  3
        Timecop.freeze(Time.now + 5)
      end

      it 'does not call the registered self-test lambda' do
        subject.healthy? #request here and test if it was run in expect below
        expect(spy_lambda_was_run?).to eq false
      end
      it 'returns the current unhealthy state' do
        expect(subject.healthy?).to be false
      end
    end

    context 'when unhealty-cache-ttl has expired' do
      before(:each) do
        subject.unhealthy_cache_ttl =  3
        subject.healthy_cache_ttl   = 10
        Timecop.freeze(Time.now + 5)
      end

      it 'calls the registered self-test lambda' do
        subject.healthy? #request here and test if it was run in expect below
        expect(spy_lambda_was_run?).to eq true
      end
      it 'returns the current unhealthy state' do
        expect(subject.healthy?).to be false
      end
    end
  end
end