fix after second issue, and make the check time constant

Author: ssinghi

lib/rotp/totp.rb

@@ -39,14 +39,17 @@ def now
     def verify(otp, drift_ahead: 0, drift_behind: 0, after: nil, at: Time.now)
       now = timeint(at)
 
-      timecode_start = timecode([now - drift_behind, after].compact.max)
+      # we need to skip time <= after
+      timecode_start = [timecode(now - drift_behind), after ? timecode(after) + 1 : nil].compact.max
       timecode_end = timecode(now + drift_ahead)
 
+      result = nil
+
       timecode_start.upto(timecode_end) do |t|
-        return t * interval if super(otp, generate_otp(t))
+        result = t * interval if super(otp, generate_otp(t))
       end
 
-      nil
+      result
     end
 
     # Returns the provisioning URI for the OTP

spec/lib/rotp/totp_spec.rb

@@ -101,31 +101,6 @@
     end
   end
 
-  def get_timecodes(at, b, a)
-    # Test the private method
-    totp.send('get_timecodes', at, b, a)
-  end
-
-  describe 'drifting timecodes' do
-    it 'should get timecodes behind' do
-      expect(get_timecodes(TEST_TIME + 15, 15, 0)).to eq([49_154_040])
-      expect(get_timecodes(TEST_TIME, 15, 0)).to eq([49_154_039, 49_154_040])
-      expect(get_timecodes(TEST_TIME, 40, 0)).to eq([49_154_038, 49_154_039, 49_154_040])
-      expect(get_timecodes(TEST_TIME, 90, 0)).to eq([49_154_037, 49_154_038, 49_154_039, 49_154_040])
-    end
-    it 'should get timecodes ahead' do
-      expect(get_timecodes(TEST_TIME, 0, 15)).to eq([49_154_040])
-      expect(get_timecodes(TEST_TIME + 15, 0, 15)).to eq([49_154_040, 49_154_041])
-      expect(get_timecodes(TEST_TIME, 0, 30)).to eq([49_154_040, 49_154_041])
-      expect(get_timecodes(TEST_TIME, 0, 70)).to eq([49_154_040, 49_154_041, 49_154_042])
-      expect(get_timecodes(TEST_TIME, 0, 90)).to eq([49_154_040, 49_154_041, 49_154_042, 49_154_043])
-    end
-    it 'should get timecodes behind and ahead' do
-      expect(get_timecodes(TEST_TIME, 30, 30)).to eq([49_154_039, 49_154_040, 49_154_041])
-      expect(get_timecodes(TEST_TIME, 60, 60)).to eq([49_154_038, 49_154_039, 49_154_040, 49_154_041, 49_154_042])
-    end
-  end
-
   describe '#verify with drift' do
     let(:verification) { totp.verify token, drift_ahead: drift_ahead, drift_behind: drift_behind, at: now }
     let(:drift_ahead) { 0 }