Possible hotfix for coveralls breakage

.circleci/config.yml

@@ -38,3 +38,7 @@ jobs:
           command: |
             sudo docker-compose run webpack npm run test-slow
             sudo docker-compose run -e COVERALLS_REPO_TOKEN=lEX6nkql7y2YFCcIXVq5ORvdvMtYzfZdG webpack npm run coverage
+      - run:
+          name: Check Coveralls coverage on staging
+          command: |
+            sudo docker-compose run web rake coverage:run

lib/tasks/coverage.rake

@@ -0,0 +1,47 @@
+COVERAGE_FILE_PATH = [
+  ENV.fetch("CIRCLE_WORKING_DIRECTORY", "./coverage_fe"),
+  "index.html"
+].join("/")
+THRESHOLD      = 0.001
+REPO_URL       = "https://api.github.com/repos/Farmbot/Farmbot-Web-App/git"\
+                 "/refs/heads/staging"
+CSS_SELECTOR   = ".fraction"
+FRACTION_DELIM = "/"
+
+# Fetch JSON over HTTP. Rails probably already has a helper for this :shrug:
+def open_json(url)
+  JSON.parse(open(url).read)
+end
+
+namespace :coverage do
+  desc "Coveralls stats stopped working :("
+  task run: :environment do
+    _, branches, _, lines = Nokogiri::HTML(open(COVERAGE_FILE_PATH))
+      .css(CSS_SELECTOR)
+      .map(&:text)
+      .map { |x| x.split(FRACTION_DELIM).map(&:to_f) }
+      .map { |x| Pair.new(*x) }
+
+    numerator     = lines.head + branches.head
+    denominator   = lines.tail + branches.tail
+    build_percent = (numerator / denominator) * 100
+
+    latest_commit_staging = open_json(REPO_URL).dig("object", "sha")
+    build_url             = "https://coveralls.io/builds/#{latest_commit_staging}.json"
+    staging_percent       = open_json(build_url).fetch("covered_percent")
+
+    diff = (build_percent - staging_percent)
+    pass = (diff > -THRESHOLD)
+
+    puts "=" * 37
+    puts "COVERAGE RESULTS"
+    puts "This build:    #{build_percent}"
+    puts "Staging build: #{staging_percent}"
+    puts "=" * 37
+    puts "Difference:    #{diff}"
+    puts "Pass?:         #{pass ? "yes" : "no"}"
+
+    exit pass ? 0 : 1
+
+  end
+end