Ensure test rake commands run immediately

Before this commit, Rails test Rake tasks only load the test files, and
the tests only run in an at_exit hook via minitest/autorun.

This prevents conditionally running tasks only when tests pass, or even
more simply in the right order. As a simple example, if you have:

task default: [:test, :rubocop]

The rubocop task will run after the test task loads the test files but
before the tests actually run.

This commit changes the test Rake tasks to shell out to the test runner
as a new process.

This diverges from previous behavior because now, any changes made in
the Rakefile or other code loaded by Rake won't be available to the
child process. However this brings the behavior of `rake test` closer to
the behavior of `rails test`.

Co-authored-by: Adrianna Chang <adrianna.chang@shopify.com>

railties/lib/rails/test_unit/runner.rb

@@ -30,9 +30,9 @@ module Rails
         end
 
         def rake_run(argv = [])
-          ARGV.replace Shellwords.split(ENV["TESTOPTS"] || "")
+          # Ensure the tests run during the Rake Task action, not when the process exits
-
+          success = system("rails", "test", *argv, *Shellwords.split(ENV["TESTOPTS"] || ""))
-          run(argv)
+          success || exit(false)
         end
 
         def run(argv = [])

railties/lib/rails/test_unit/testing.rake

@@ -8,8 +8,6 @@ task default: :test
 
 desc "Runs all tests in test folder except system ones"
 task :test do
-  $: << "test"
-
   if ENV.key?("TEST")
     Rails::TestUnit::Runner.rake_run([ENV["TEST"]])
   else
@@ -30,35 +28,29 @@ namespace :test do
 
   ["models", "helpers", "channels", "controllers", "mailers", "integration", "jobs", "mailboxes"].each do |name|
     task name => "test:prepare" do
-      $: << "test"
       Rails::TestUnit::Runner.rake_run(["test/#{name}"])
     end
   end
 
   desc "Runs all tests, including system tests"
   task all: "test:prepare" do
-    $: << "test"
     Rails::TestUnit::Runner.rake_run(["test/**/*_test.rb"])
   end
 
   task generators: "test:prepare" do
-    $: << "test"
     Rails::TestUnit::Runner.rake_run(["test/lib/generators"])
   end
 
   task units: "test:prepare" do
-    $: << "test"
     Rails::TestUnit::Runner.rake_run(["test/models", "test/helpers", "test/unit"])
   end
 
   task functionals: "test:prepare" do
-    $: << "test"
     Rails::TestUnit::Runner.rake_run(["test/controllers", "test/mailers", "test/functional"])
   end
 
   desc "Run system tests only"
   task system: "test:prepare" do
-    $: << "test"
     Rails::TestUnit::Runner.rake_run(["test/system"])
   end
 end

railties/test/application/test_runner_test.rb

@@ -686,7 +686,7 @@ module ApplicationTests
     def test_rake_passes_TESTOPTS_to_minitest
       create_test_file :models, "account"
       output = Dir.chdir(app_path) { `bin/rake test TESTOPTS=-v` }
-      assert_match "AccountTest#test_truth", output, "passing TEST= should run selected test"
+      assert_match "AccountTest#test_truth", output, "passing TESTOPTS= should be sent to the test runner"
     end
 
     def test_running_with_ruby_gets_test_env_by_default
@@ -745,6 +745,28 @@ module ApplicationTests
       assert_match "ar_internal_metadata", output
     end
 
+    def test_rake_runs_tests_before_other_tasks_when_specified
+      app_file "Rakefile", <<~RUBY, "a"
+        task :echo do
+          puts "echo"
+        end
+      RUBY
+      output = Dir.chdir(app_path) { `bin/rake test echo` }
+      assert_equal "echo", output.split("\n").last
+    end
+
+    def test_rake_exits_on_failure
+      create_test_file :models, "post", pass: false
+      app_file "Rakefile", <<~RUBY, "a"
+        task :echo do
+          puts "echo"
+        end
+      RUBY
+      output = Dir.chdir(app_path) { `bin/rake test echo` }
+      assert_no_match "echo", output
+      assert_not_predicate $?, :success?
+    end
+
     def test_warnings_option
       app_file "test/models/warnings_test.rb", <<-RUBY
         require "test_helper"