Move profile JSON formatting into Profile class

src/spectator/formatting/json_formatter.cr

@@ -33,20 +33,8 @@ module Spectator::Formatting
 
     # Adds the profiling information to the document.
     def dump_profile(notification)
-      profile = notification.profile
-
       @json.field("profile") do
-        @json.object do
+        notification.profile.to_json(@json)
-          @json.field("examples") do
-            @json.array do
-              profile.each(&.to_json(@json))
-            end
-          end
-
-          @json.field("slowest", profile.max_of(&.result.elapsed).total_seconds)
-          @json.field("total", profile.time.total_seconds)
-          @json.field("percentage", profile.percentage)
-        end
       end
     end
 

src/spectator/profile.cr

@@ -1,3 +1,6 @@
+require "json"
+require "./example"
+
 module Spectator
   # Information about the runtimes of examples.
   class Profile
@@ -39,5 +42,20 @@ module Spectator
     def percentage
       time / @total_time * 100
     end
+
+    # Produces a JSON fragment containing the profiling information.
+    def to_json(json : JSON::Builder)
+      json.object do
+        json.field("examples") do
+          json.array do
+            @slowest.each(&.to_json(json))
+          end
+        end
+
+        json.field("slowest", @slowest.max_of(&.result.elapsed).total_seconds)
+        json.field("total", time.total_seconds)
+        json.field("percentage", percentage)
+      end
+    end
   end
 end