Add FakeFS gem to test suite

Gemfile

@@ -6,7 +6,8 @@ gem "ed25519"
 gem "thor"
 
 group :dev do
-  gem "rspec"
+  gem "fakefs"
   gem "pry"
+  gem "rspec"
   gem "simplecov"
 end

Gemfile.lock

@@ -5,6 +5,7 @@ GEM
     diff-lcs (1.3)
     docile (1.3.2)
     ed25519 (1.2.4)
+    fakefs (0.20.1)
     json (2.2.0)
     method_source (0.9.2)
     pry (0.12.2)
@@ -35,6 +36,7 @@ PLATFORMS
 
 DEPENDENCIES
   ed25519
+  fakefs
   pry
   rspec
   simplecov

spec/pigeon/storage_spec.rb

@@ -0,0 +1,10 @@
+require "spec_helper"
+
+RSpec.describe Pigeon::Storage do
+  include FakeFS::SpecHelpers
+  it "does something to the filesystem" do
+    FakeFS.with_fresh do
+      expect(2 + 2).to eq(4)
+    end
+  end
+end

spec/spec_helper.rb

@@ -1,5 +1,7 @@
 require "pry"
 require "simplecov"
+require "fakefs/spec_helpers"
+
 SimpleCov.start
 require_relative File.join("..", "dist", "pigeon")
 # See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration