diff --git a/.rubocop.yml b/.rubocop.yml
index aa078ef5..a889a2fd 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -84,3 +84,65 @@ Layout/LineLength:
 
 Style/Documentation:
   Enabled: false
+
+Style/SymbolArray:
+  Enabled: true
+  EnforcedStyle: percent
+
+Style/WordArray:
+  Enabled: true
+  EnforcedStyle: percent
+
+Performance/AncestorsInclude: # new in 1.7
+  Enabled: true
+
+Performance/BigDecimalWithNumericArgument: # new in 1.7
+  Enabled: true
+
+Performance/BlockGivenWithExplicitBlock: # new in 1.9
+  Enabled: true
+
+Performance/CollectionLiteralInLoop: # new in 1.8
+  Enabled: true
+
+Performance/ConcurrentMonotonicTime: # new in 1.12
+  Enabled: true
+
+Performance/ConstantRegexp: # new in 1.9
+  Enabled: true
+
+Performance/MapCompact: # new in 1.11
+  Enabled: true
+
+Performance/MethodObjectAsBlock: # new in 1.9
+  Enabled: true
+
+Performance/RedundantEqualityComparisonBlock: # new in 1.10
+  Enabled: true
+
+Performance/RedundantSortBlock: # new in 1.7
+  Enabled: true
+
+Performance/RedundantSplitRegexpArgument: # new in 1.10
+  Enabled: true
+
+Performance/RedundantStringChars: # new in 1.7
+  Enabled: true
+
+Performance/ReverseFirst: # new in 1.7
+  Enabled: true
+
+Performance/SortReverse: # new in 1.7
+  Enabled: true
+
+Performance/Squeeze: # new in 1.7
+  Enabled: true
+
+Performance/StringIdentifierArgument: # new in 1.13
+  Enabled: true
+
+Performance/StringInclude: # new in 1.7
+  Enabled: true
+
+Performance/Sum: # new in 1.8
+  Enabled: true
diff --git a/app/controllers/spam_controller.rb b/app/controllers/spam_controller.rb
index 6321d78b..dd9ef780 100644
--- a/app/controllers/spam_controller.rb
+++ b/app/controllers/spam_controller.rb
@@ -24,7 +24,7 @@ class SpamController < ApplicationController
   include ModerationGuards
 
   before_action :require_login
-  before_action { logged_in_as(['admin', 'moderator'], 'moderate maps and users') }
+  before_action { logged_in_as(%w[admin moderator], 'moderate maps and users') }
 
   def spam_map
     @map = Map.find(params[:id])
diff --git a/app/controllers/tags_controller.rb b/app/controllers/tags_controller.rb
index e59062bf..10ca5056 100644
--- a/app/controllers/tags_controller.rb
+++ b/app/controllers/tags_controller.rb
@@ -16,7 +16,7 @@ class TagsController < ApplicationController
     @tag = Tag.find_by_name(params[:id])
     @maps = @tag.maps.paginate(page: params[:page], per_page: 24)
     @title = "Maps tagged with ' #{@tag.name} '"
-    tag = Tag.where(name: 'featured').first # note that this is not a join table but the .maps method still works
+    tag = Tag.where(name: 'featured').first # NOTE: that this is not a join table but the .maps method still works
     @unpaginated = true
     @authors = User.where(login: tag.maps.collect(&:author)) if tag
     @authors ||= []
diff --git a/app/models/map.rb b/app/models/map.rb
index bb799b8c..2c762e6b 100755
--- a/app/models/map.rb
+++ b/app/models/map.rb
@@ -62,11 +62,11 @@ class Map < ApplicationRecord
   def self.bbox(minlat, minlon, maxlat, maxlon, tag = nil)
     if tag.nil?
       Map.where(['lat > ? AND lat < ? AND lon > ? AND lon < ?',
-                 minlat, maxlat, minlon, maxlon])
+                 minlat, maxlat, minlon, maxlon,])
     else
       Map.where(['lat > ? AND lat < ? AND lon > ? AND lon < ?',
-                 minlat, maxlat, minlon, maxlon])
-         .joins(:tags).where("tags.name = ?", tag)
+                 minlat, maxlat, minlon, maxlon,])
+        .joins(:tags).where("tags.name = ?", tag)
     end
   end
 
@@ -91,10 +91,10 @@ class Map < ApplicationRecord
 
   def self.search(query)
     query = query.squeeze(' ').strip
-    Map.active
-       .where(['author LIKE ? OR name LIKE ?
-                OR location LIKE ? OR description LIKE ?',
-               "%#{query}%", "%#{query}%", "%#{query}%", "%#{query}%"])
+    Map.active.where([
+      'author LIKE ? OR name LIKE ? OR location LIKE ? OR description LIKE ?',
+      "%#{query}%", "%#{query}%", "%#{query}%", "%#{query}%",
+    ])
   end
 
   def self.featured
@@ -132,9 +132,10 @@ class Map < ApplicationRecord
   end
 
   def self.maps_nearby(lat:, lon:, dist:)
-    Map.active
-       .where(['lat>? AND lat<? AND lon>? AND lon<?',
-               lat - dist, lat + dist, lon - dist, lon + dist])
+    Map.active.where([
+      'lat>? AND lat<? AND lon>? AND lon<?',
+      lat - dist, lat + dist, lon - dist, lon + dist,
+    ])
   end
 
   def nodes
@@ -169,8 +170,7 @@ class Map < ApplicationRecord
     placed_warpables.each do |warpable|
       pxperms << 100.00 / warpable.cm_per_pixel if warpable.placed?
     end
-    average = (pxperms.inject { |sum, n| sum + n }) / pxperms.length
-    average
+    pxperms.sum / pxperms.length
   end
 
   def best_cm_per_pixel
@@ -202,7 +202,7 @@ class Map < ApplicationRecord
         res = 1 if res.zero? # let's not ever try to go for infinite resolution
         scales << res unless res.nil?
       end
-      total_sum = (scales.inject { |sum, n| sum + n }) if scales
+      total_sum = scales.sum unless scales.empty?
       average = total_sum / count if total_sum
       average
     else
diff --git a/app/models/warpable.rb b/app/models/warpable.rb
index e6f1b6a1..099295be 100755
--- a/app/models/warpable.rb
+++ b/app/models/warpable.rb
@@ -19,7 +19,7 @@ class Warpable < ApplicationRecord
   belongs_to :map, optional: true
   belongs_to :user, optional: true
 
-  has_paper_trail on: %i(create update), only: %i(nodes)
+  has_paper_trail on: %i(create update), only: :nodes
 
   # overriding JSON formatting for Leaflet.DistortableImage
   def as_json(options = {})
@@ -32,20 +32,24 @@ class Warpable < ApplicationRecord
 
   # JSON formatting for file upload plugin
   def fup_json
-    { "name" => read_attribute(:image_filename),
+    {
+      "name" => read_attribute(:image_filename),
       "size" => read_attribute(:image_size),
       "url" => image.url(:medium),
       "original_url" => image.url(:original),
       "id" => read_attribute(:id),
       "thumbnail_url" => image.url(:thumb),
       "delete_url" => image.url,
-      "delete_type" => "DELETE" }
+      "delete_type" => "DELETE",
+    }
   end
 
   def fup_error_json
-    { "name" => read_attribute(:image_filename),
+    {
+      "name" => read_attribute(:image_filename),
       "size" => read_attribute(:image_size),
-      "error" => errors["base"] }
+      "error" => errors["base"],
+    }
   end
 
   after_save :save_dimensions
@@ -135,14 +139,17 @@ class Warpable < ApplicationRecord
   # needs update for Paperclip!!
   require 'open-uri'
   attr_reader :url
+
   def url=(uri)
     nil if uri.blank?
 
-    io = (begin
-            URI.parse(uri).open
-          rescue StandardError
-            nil
-          end)
+    io = (
+      begin
+        URI.parse(uri).open
+      rescue StandardError
+        nil
+      end
+    )
     (class << io; self; end;).class_eval do
       define_method(:original_filename) { base_uri.path.split('/').last }
     end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 7f991a18..66576e9f 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -1,8 +1,12 @@
 
 require_relative '../config/environment'
 require 'simplecov'
-require 'codecov'
-SimpleCov.formatter = SimpleCov::Formatter::Codecov
+
+if ENV['CI'] == 'true'
+  require 'codecov'
+  SimpleCov.formatter = SimpleCov::Formatter::Codecov
+end
+
 SimpleCov.start
 
 require "rack_session_access/capybara"