(QENG-2208) Move Sinatra Helpers to own file

This moves the inline Helpers contained in V1.rb to their own file:
helpers.rb. In making this change, any API.settings call was removed
from the helper method itself and passed through from V1.

This also adds tests for hostname shortener and validate date string.

spec/vmpooler/api/helpers_spec.rb

@@ -0,0 +1,40 @@
+require 'spec_helper'
+
+# A class for testing purposes that includes the Helpers.
+# this is impersonating V1's `helpers do include Helpers end`
+#
+# This is the subject used throughout the test file.
+#
+class TestHelpers
+  include Vmpooler::API::Helpers
+end
+
+describe Vmpooler::API::Helpers do
+
+  subject { TestHelpers.new }
+
+  describe '#hostname_shorten' do
+    [
+        ['example.com', 'not-example.com', 'example.com'],
+        ['example.com', 'example.com', 'example.com'],
+        ['sub.example.com', 'example.com', 'sub'],
+        ['example.com', nil, 'example.com']
+    ].each do |hostname, domain, expected|
+      it { expect(subject.hostname_shorten(hostname, domain)).to eq expected }
+    end
+  end
+
+  describe '#validate_date_str' do
+    [
+        ['2015-01-01', true],
+        [nil, false],
+        [false, false],
+        [true, false],
+        ['01-01-2015', false],
+        ['1/1/2015', false]
+    ].each do |date, expected|
+      it { expect(subject.validate_date_str(date)).to eq expected }
+    end
+  end
+
+end