Add duration validation and test

app/models/uncut.rb

@@ -1,5 +1,6 @@
 class Uncut < MediaResource
   validates :medium, inclusion: {in: %w[audio]}, if: :status_complete?
+  validates :duration, numericality: {greater_than: 0}, if: :status_complete?
   validate :validate_segmentation
 
   before_validation :set_defaults

test/models/uncut_test.rb

@@ -24,7 +24,7 @@
 
       uncut.segmentation[0] = [0.5, 1]
       uncut.segmentation[2] = [3.5, nil]
-      episode.contents[0].update(status: "complete", medium: "audio")
+      episode.contents[0].update!(status: "complete", medium: "audio", duration: 1)
       uncut.slice_contents
 
       assert_equal 5, episode.contents.size
@@ -50,6 +50,18 @@
       uncut.medium = "audio"
       assert uncut.valid?
     end
+
+    it "must have a duration greater than 0 when complete" do
+      assert uncut.valid?
+      assert uncut.status_created?
+
+      uncut.duration = 0
+      uncut.status = "complete"
+      refute uncut.valid?
+
+      uncut.duration = 100
+      assert uncut.valid?
+    end
   end
 
   describe "#validate_segmentation" do