Add a Gitlab::Json wrapper

Implements a GitLab JSON wrapper to allow deprecated usage of the
JSON gem, which allows us to upgrade the gem to a more modern
version.

lib/gitlab/json.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Json
+    class << self
+      def parse(*args)
+        adapter.parse(*args)
+      end
+
+      def parse!(*args)
+        adapter.parse!(*args)
+      end
+
+      def dump(*args)
+        adapter.dump(*args)
+      end
+
+      def generate(*args)
+        adapter.generate(*args)
+      end
+
+      def pretty_generate(*args)
+        adapter.pretty_generate(*args)
+      end
+
+      private
+
+      def adapter
+        ::JSON
+      end
+    end
+  end
+end

spec/lib/gitlab/json_spec.rb

+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe Gitlab::Json do
+  describe ".parse" do
+    it "parses an object" do
+      expect(subject.parse('{ "foo": "bar" }')).to eq({ "foo" => "bar" })
+    end
+
+    it "parses an array" do
+      expect(subject.parse('[{ "foo": "bar" }]')).to eq([{ "foo" => "bar" }])
+    end
+
+    it "raises an error on a string" do
+      expect { subject.parse('"foo"') }.to raise_error(JSON::ParserError)
+    end
+
+    it "raises an error on a true bool" do
+      expect { subject.parse("true") }.to raise_error(JSON::ParserError)
+    end
+
+    it "raises an error on a false bool" do
+      expect { subject.parse("false") }.to raise_error(JSON::ParserError)
+    end
+  end
+
+  describe ".parse!" do
+    it "parses an object" do
+      expect(subject.parse!('{ "foo": "bar" }')).to eq({ "foo" => "bar" })
+    end
+
+    it "parses an array" do
+      expect(subject.parse!('[{ "foo": "bar" }]')).to eq([{ "foo" => "bar" }])
+    end
+
+    it "raises an error on a string" do
+      expect { subject.parse!('"foo"') }.to raise_error(JSON::ParserError)
+    end
+
+    it "raises an error on a true bool" do
+      expect { subject.parse!("true") }.to raise_error(JSON::ParserError)
+    end
+
+    it "raises an error on a false bool" do
+      expect { subject.parse!("false") }.to raise_error(JSON::ParserError)
+    end
+  end
+
+  describe ".dump" do
+    it "dumps an object" do
+      expect(subject.dump({ "foo" => "bar" })).to eq('{"foo":"bar"}')
+    end
+
+    it "dumps an array" do
+      expect(subject.dump([{ "foo" => "bar" }])).to eq('[{"foo":"bar"}]')
+    end
+
+    it "dumps a string" do
+      expect(subject.dump("foo")).to eq('"foo"')
+    end
+
+    it "dumps a true bool" do
+      expect(subject.dump(true)).to eq("true")
+    end
+
+    it "dumps a false bool" do
+      expect(subject.dump(false)).to eq("false")
+    end
+  end
+
+  describe ".generate" do
+    it "delegates to the adapter" do
+      args = [{ foo: "bar" }]
+
+      expect(JSON).to receive(:generate).with(*args)
+
+      subject.generate(*args)
+    end
+  end
+
+  describe ".pretty_generate" do
+    it "delegates to the adapter" do
+      args = [{ foo: "bar" }]
+
+      expect(JSON).to receive(:pretty_generate).with(*args)
+
+      subject.pretty_generate(*args)
+    end
+  end
+end