Create hatchet tests to be shared across languages

.gitignore

@@ -1,2 +1,3 @@
 .anvil
 .DS_Store
+repos/*

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Node.js Buildpack Changelog
 
 ## main
+- Added Hatchet regression tests ([#833](https://github.com/heroku/heroku-buildpack-nodejs/pull/833))
 
 ## v175 (2020-08-13)
 - Install Yarn version at 1.22.x when not specified in package.json engines ([#817](https://github.com/heroku/heroku-buildpack-nodejs/pull/817))

hatchet.json

@@ -1 +1,8 @@
-{}
+{
+  "heroku": [
+    "heroku/node-js-getting-started"
+  ],
+  "nodejs": [
+    "sharpstone/default-node"
+  ]
+}

hatchet.lock

@@ -0,0 +1,5 @@
+---
+- - "./repos/heroku/node-js-getting-started"
+  - master
+- - "./repos/nodejs/default-node"
+  - master

spec/hatchet/absolute_path_spec.rb

@@ -0,0 +1,14 @@
+require_relative '../spec_helper'
+
+#Test that all paths set by the buildpack are absolute instead of relative
+describe "Buildpack paths" do
+  it "are absolute" do
+    buildpacks = [
+      :default,
+      "https://github.com/sharpstone/force_absolute_paths_buildpack"
+    ]
+    Hatchet::Runner.new("node-js-getting-started", buildpacks: buildpacks).deploy do |app|
+      #deploy works
+    end
+  end
+end

spec/hatchet/ci_spec.rb

@@ -0,0 +1,12 @@
+require_relative '../spec_helper'
+
+#Test CI deploys run tests and use the cache
+describe "Heroku CI" do
+  it "Uses the cache" do
+    Hatchet::Runner.new("node-js-getting-started").run_ci do |test_run|
+      expect(test_run.output).to_not include("Restoring cache")
+      test_run.run_again
+      expect(test_run.output).to include("Restoring cache")
+    end
+  end
+end

spec/hatchet/getting_started_spec.rb

@@ -0,0 +1,10 @@
+require_relative '../spec_helper'
+
+#Test deploying the getting started guide works
+describe "Heroku node getting started" do
+  it "clears runtime cache" do
+    Hatchet::Runner.new("node-js-getting-started").deploy do |app|
+      #Deploy works
+    end
+  end
+end

spec/hatchet/stack_spec.rb

@@ -0,0 +1,26 @@
+require_relative "../spec_helper"
+
+describe "Stack Changes" do
+  #Test upgrading stack invalidates the cache
+  it "should not restore cached directories" do
+    app = Hatchet::Runner.new("default-node", allow_failure: true, stack: "heroku-18").setup!
+    app.deploy do |app, heroku|
+      app.update_stack("heroku-16")
+      run!('git commit --allow-empty -m "heroku-16 migrate"')
+      app.push!
+      expect(app.output).to include("Cached directories were not restored due to a change in version of node, npm, yarn or stack")
+    end
+  end
+
+#Test cache for regular deploys is used on repeated deploys
+  it "should not restore cache if the stack did not change" do
+    app = Hatchet::Runner.new('default-node', stack: "heroku-16").setup!
+    app.deploy do |app, heroku|
+      app.update_stack("heroku-16")
+      run!('git commit --allow-empty -m "cedar migrate"')
+      app.push!
+      expect(app.output).to_not include("Cached directories were not restored due to a change in version of node, npm, yarn or stack")
+      expect(app.output).to include("not cached - skipping")
+    end
+  end
+end

spec/hatchet/version_spec.rb

@@ -0,0 +1,19 @@
+require_relative '../spec_helper'
+
+#Test that builds fail when a bad version is specified
+describe "bad node version" do
+  it "gives a helpful error" do
+    Hatchet::Runner.new("spec/fixtures/repos/default-node", allow_failure: true).tap do |app|
+      app.before_deploy do
+        File.open("package.json", "w+") do |f|
+          f.write '{"engines": {
+            "node": "14.x.badversion"
+          }}'
+        end
+      end
+      app.deploy do
+        expect(app.output).to include("Invalid semantic version \"14.x.badversion\"")
+      end
+    end
+  end
+end

spec/spec_helper.rb

@@ -1,3 +1,5 @@
+ENV['HATCHET_BUILDPACK_BASE'] = 'https://github.com/heroku/heroku-buildpack-nodejs.git'
+
 require 'rspec/core'
 require 'hatchet'
 require 'fileutils'