Parse git remote name to determine Heroku app

Several reports have matched #72, which was affecting the `restore`
command for some users. The cause turned out to be local folder names
not matching the name of the Heroku app. Now that Heroku tracks Git
remotes, we can take advantage of the Git remote to correctly identify
the app name even the local folder name doesn't match.

While this requirement has been present for the entirety of Parity's
existence, it stopped being a problem for most commands once Heroku
introduced remotes. I inadvertently reintroduced this requirement in
ad2c21a when we started automatically
bypassing confirmation arguments for restores to non-production
environments.

I've moved the `git` and `rake` dependencies to the gemspec, as they do
not appear to be installed by default if they are listed in the Gemfile.
Fix #72.

Gemfile

@@ -2,5 +2,4 @@ source 'https://rubygems.org'
 
 gemspec
 
-gem 'rake'
-gem 'rspec'
+gem "rspec"

README.md

@@ -98,8 +98,6 @@ Parity expects:
 * A `production` remote pointing to the production Heroku app.
 * There is a `config/database.yml` file that can be parsed as YAML for
   `['development']['database']`.
-* The Heroku apps are named like `app-staging` and `app-production`
-  where `app` is equal to `basename $PWD`.
 
 Customization
 -------------

lib/parity.rb

@@ -3,6 +3,7 @@
 require "parity/version"
 require "parity/environment"
 require "parity/usage"
+require "git"
 require "open3"
 require "pathname"
 require "uri"

lib/parity/environment.rb

@@ -125,12 +125,12 @@ def raw_redis_url
       )[0].strip
     end
 
-    def heroku_app_name
-      [basename, environment].join('-')
+    def git_remote
+      Git.init.remote(environment).url
     end
 
-    def basename
-      Dir.pwd.split("/").last
+    def heroku_app_name
+      git_remote.split(":").last.split(".").first
     end
 
     def run_migrations?

parity.gemspec

@@ -17,4 +17,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
   spec.summary = "Shell commands for development, staging, and production parity."
   spec.version = Parity::VERSION
+
+  spec.add_dependency "git", "~> 1.2"
+  spec.add_dependency "rake", "~> 10.4"
 end

spec/parity/environment_spec.rb

@@ -31,8 +31,26 @@
     expect(Kernel).to have_received(:system).with(heroku_backup)
   end
 
+  it "correctly connects to the Heroku app when the $PWD's name does not match the app's name" do
+    backup = stub_parity_backup
+    stub_git_remote(base_name: "parity-integration", environment: "staging")
+    allow(Parity::Backup).to receive(:new).and_return(backup)
+
+    Parity::Environment.new("staging", ["restore", "production"]).run
+
+    expect(Parity::Backup).
+      to have_received(:new).
+      with(
+        from: "production",
+        to: "staging",
+        additional_args: "--confirm parity-integration-staging",
+      )
+    expect(backup).to have_received(:restore)
+  end
+
   it "restores backups from production to staging" do
-    backup = double("backup", restore: nil)
+    backup = stub_parity_backup
+    stub_git_remote(environment: "staging")
     allow(Parity::Backup).to receive(:new).and_return(backup)
 
     Parity::Environment.new("staging", ["restore", "production"]).run
@@ -48,7 +66,8 @@
   end
 
   it "restores using restore-from" do
-    backup = double("backup", restore: nil)
+    backup = stub_parity_backup
+    stub_git_remote(environment: "staging")
     allow(Parity::Backup).to receive(:new).and_return(backup)
 
     Parity::Environment.new("staging", ["restore-from", "production"]).run
@@ -64,7 +83,8 @@
   end
 
   it "passes the confirm argument when restoring to a non-prod environment" do
-    backup = double("backup", restore: nil)
+    backup = stub_parity_backup
+    stub_git_remote(environment: "staging")
     allow(Parity::Backup).to receive(:new).and_return(backup)
 
     Parity::Environment.new("staging", ["restore", "production"]).run
@@ -79,7 +99,7 @@
   end
 
   it "restores backups from production to development" do
-    backup = double("backup", restore: nil)
+    backup = stub_parity_backup
     allow(Parity::Backup).to receive(:new).and_return(backup)
 
     Parity::Environment.new("development", ["restore", "production"]).run
@@ -90,7 +110,7 @@
   end
 
   it "restores backups from staging to development" do
-    backup = double("backup", restore: nil)
+    backup = stub_parity_backup
     allow(Parity::Backup).to receive(:new).and_return(backup)
 
     Parity::Environment.new("development", ["restore", "staging"]).run
@@ -101,7 +121,8 @@
   end
 
   it "does not allow restoring backups into production" do
-    backup = double("backup", restore: nil)
+    backup = stub_parity_backup
+    stub_git_remote
     allow(Parity::Backup).to receive(:new).and_return(backup)
     allow($stdout).to receive(:puts)
 
@@ -323,4 +344,18 @@ def stub_migration_path_check(result)
 
     path_stub
   end
+
+  def stub_git_remote(base_name: "parity", environment: "staging")
+    git_remote = instance_double(
+      "Git::Remote",
+      url: "[email protected]:#{base_name}-#{environment}.git",
+    )
+    git = instance_double("Git::Base")
+    allow(git).to receive(:remote).with("staging").and_return(git_remote)
+    allow(Git).to receive(:init).and_return(git)
+  end
+
+  def stub_parity_backup
+    instance_double("Parity::Backup", restore: nil)
+  end
 end