fix device throttle update bug

app/models/device.rb

@@ -111,18 +111,18 @@ class Device < ApplicationRecord
     Rails.cache.write(CACHE_KEY % self.id, Device.new(self.as_json))
   end
 
-  # Sets the `throttled_at` field, but only if it is unpopulated.
-  # Performs no-op if `throttled_at` was already set.
+  # Sets the `throttled_until` and `throttled_at` fields if unpopulated or
+  # the throttle time period increases. Notifies user of cooldown period.
   def maybe_throttle(violation)
+    end_t = violation.ends_at
     # Some log validation errors will result in until_time being `nil`.
-    if (violation && throttled_until.nil?)
-      et = violation.ends_at
-      reload.update_attributes!(throttled_until: et,
+    if (violation && (throttled_until.nil? || end_t > throttled_until))
+      reload.update_attributes!(throttled_until: end_t,
                                 throttled_at: Time.now)
       refresh_cache
-      cooldown = et.in_time_zone(self.timezone || "UTC").strftime("%I:%M%p")
+      cooldown = end_t.in_time_zone(self.timezone || "UTC").strftime("%I:%M%p")
       info = [violation.explanation, cooldown]
-      cooldown_notice(THROTTLE_ON % info, et, "warn")
+      cooldown_notice(THROTTLE_ON % info, end_t, "warn")
     end
   end
 

spec/models/device_spec.rb

@@ -79,6 +79,18 @@ describe Device do
     expect(device.throttled_until).to eq(violation.ends_at)
   end
 
+  it "increases a device throttle time period" do
+    expect(device).to receive(:tell).and_return(Log.new)
+    previous_throttle = Time.now - 1.minute
+    device.update_attributes!(throttled_until: previous_throttle)
+    expect(device.throttled_until).to eq(previous_throttle)
+    five_minutes = ThrottlePolicy::TimePeriod.new(5.minutes, Time.now + 1.minute)
+    rule = ThrottlePolicy::Rule.new(five_minutes, 500)
+    violation = ThrottlePolicy::Violation.new(rule)
+    device.maybe_throttle(violation)
+    expect(device.throttled_until).to eq(violation.ends_at)
+  end
+
   it "unthrottles a runaway device" do
     expect(device).to receive(:tell).and_return(Log.new)
     example = Time.now - 1.minute