Add CLI specs using aruba gem (#43)

This PR adds `aruba` to the project and also adds some CLI specs. This
is my first time using the gem so there may be better ways of doing
things.

Gemfile

@@ -6,6 +6,7 @@ gem "rake"
 gem "rspec"
 
 group :development, :test do
+  gem "aruba", "~> 2.1.0", require: false
   gem "byebug"
   gem "guard-rspec", require: false
 
@@ -17,7 +18,3 @@ group :development, :test do
     gem "pry-byebug", require: false
   end
 end
-
-group :test do
-  gem "git", require: false
-end

exe/annotaterb

@@ -1,7 +1,7 @@
 #!/usr/bin/env ruby
 # frozen_string_literal: true
 
-unless File.exist?("./Rakefile") || File.exist?("./Gemfile")
+if !File.exist?("./Rakefile") && !File.exist?("./Gemfile")
   abort "Please run annotaterb from the root of the project."
 end
 

spec/integration/cli.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+RSpec.describe "CLI", type: "aruba" do
+  context "when running in a non-Rails project directory" do
+    before do
+      # Assumes there's no Rakefile or Gemfile
+      run_command("annotaterb")
+    end
+
+    let(:error_message) { "Please run annotaterb from the root of the project." }
+
+    it "exits and outputs an error message" do
+      expect(last_command_started).to have_exit_status(1)
+      expect(last_command_started).to have_output_on_stderr(error_message)
+    end
+  end
+
+  context "when running in a directory with a Rakefile and a Gemfile" do
+    before do
+      touch("Rakefile", "Gemfile")
+      run_command("annotaterb")
+    end
+
+    let(:help_banner_fragment) { "Usage: annotaterb [command] [options]" }
+
+    it "outputs the help message" do
+      expect(last_command_started).to be_successfully_executed
+      expect(last_command_started.stdout).to include(help_banner_fragment)
+    end
+  end
+end

spec/support/aruba.rb

@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require "aruba/rspec"