(QENG-1906) Add spec tests for Janitor

Add spec tests to verify Janitor deletes stale vms correctly. This
required a small refactor of Janitor to move the logic out of the for
loop.

spec/vmpooler/janitor_spec.rb

@@ -0,0 +1,71 @@
+require 'spec_helper'
+
+describe 'Janitor' do
+  let(:logger) { double('logger') }
+  let(:redis) { double('redis') }
+  let(:data_ttl) { 3 } # number of hours to retain
+  let(:old_destroy) { '2015-01-30 11:24:30 -0700' }
+  let(:fut_destroy) { '3015-01-30 11:24:30 -0700' }
+
+  subject { Vmpooler::Janitor.new(logger, redis, data_ttl) }
+
+  before do
+    allow(redis).to receive(:hgetall).with('key1').and_return({'destroy' => old_destroy})
+    allow(redis).to receive(:hgetall).with('key2').and_return({'destroy' => old_destroy})
+    allow(redis).to receive(:hgetall).with('key3').and_return({'destroy' => Time.now.to_s})
+    allow(redis).to receive(:hgetall).with('key4').and_return({'destroy' => Time.now.to_s})
+    allow(redis).to receive(:hgetall).with('key5').and_return({'destroy' => fut_destroy})
+
+    allow(redis).to receive(:del)
+  end
+
+  describe '#find_stale_vms' do
+
+    context 'has stale vms' do
+
+      it 'has one key' do
+        allow(redis).to receive(:keys) {['key1']}
+
+        expect(redis).to receive(:del).with('key1').once
+        expect(redis).to receive(:hgetall).with('key1').once
+        expect(redis).not_to receive(:hgetall).with('key2')
+
+        subject.find_stale_vms
+      end
+
+      it 'has two keys' do
+        allow(redis).to receive(:keys) {(%w(key1 key2))}
+
+        expect(redis).to receive(:hgetall).twice
+        expect(redis).to receive(:del).with('key1')
+        expect(redis).to receive(:del).with('key2')
+
+        subject.find_stale_vms
+      end
+
+      it 'has 5 keys and 2 stales' do
+        allow(redis).to receive(:keys) {(%w(key1 key2 key3 key4 key5))}
+
+
+        expect(redis).to receive(:hgetall).exactly(5).times
+        expect(redis).to receive(:del).with('key1')
+        expect(redis).to receive(:del).with('key2')
+        expect(redis).not_to receive(:del).with('key3')
+        expect(redis).not_to receive(:del).with('key4')
+        expect(redis).not_to receive(:del).with('key5')
+
+        subject.find_stale_vms
+      end
+    end
+
+    it 'does not have stale vms' do
+      allow(redis).to receive(:keys).and_return(['key1'])
+      allow(redis).to receive(:hgetall).with('key1') {{'destroy' => Time.now.to_s}}
+      allow(redis).to receive(:del).with('key1')
+
+      expect(redis).not_to receive(:del).with('key1')
+
+      subject.find_stale_vms
+    end
+  end
+end