Fix multiple test leaks and inconsistencies in railties tests

`Rails` is a constant (a module), and `Rails.app_class` and
`Rails.application` are memoized (see
[here](https://github.com/rails/rails/blob/3872bc0e54d32e8bf3a6299b0bfe173d94b072fc/railties/lib/rails.rb#L35-L41)).

`Rails.application` will get memoized the first time it's called, and
then leak to following tests in the run.
This can cause problems when using setups such as `build_app`, which is
supposed to generate a new application from template, which
`Rails.application` would then point at.

By ensuring that `Rails.app_class` and `Rails.application` have been
nullified at the top of `build_app` and restoring at teardown, we can
prevent some leaks.

To reproduce, run `bin/test --seed 65206 -v`.
Without this fix, you'll notice the first failing test is
`Rails::Command::RoutesTest#test_rails_routes_with_namespaced_controller_search_key`.
With the fix, you can confirm that test and many others will pass.
Depending on the order tests run, `Rails.application might get memoized

Also fixes some failures cause by an inconsistent `Rails.root` depending
on whether tests are ran with `bin/test` or through `rake.

Co-Authored-By: Jean Boussier <[email protected]>

Author: davidstosik

railties/lib/rails/test_unit/runner.rb

@@ -125,6 +125,7 @@ def path_argument?(arg)
           def list_tests(patterns)
             tests = Rake::FileList[patterns.any? ? patterns : default_test_glob]
             tests.exclude(default_test_exclude_glob) if patterns.empty?
+            tests.exclude(%r{test/isolation/assets/node_modules})
             tests
           end
 

railties/test/abstract_unit.rb

@@ -16,7 +16,7 @@
 
 module TestApp
   class Application < Rails::Application
-    config.root = __dir__
+    config.root = File.expand_path("../../", __FILE__)
   end
 end
 

railties/test/generators/namespaced_generators_test.rb

@@ -12,8 +12,14 @@ class NamespacedGeneratorTestCase < Rails::Generators::TestCase
 
   def setup
     super
+    @old_namespace = Rails::Generators.namespace
     Rails::Generators.namespace = TestApp
   end
+
+  def teardown
+    super
+    Rails::Generators.namespace = @old_namespace
+  end
 end
 
 class NamespacedControllerGeneratorTest < NamespacedGeneratorTestCase

railties/test/isolation/abstract_unit.rb

@@ -105,6 +105,10 @@ def assert_welcome(resp)
   module Generation
     # Build an application by invoking the generator and going through the whole stack.
     def build_app(options = {})
+      @prev_rails_app_class = Rails.app_class
+      @prev_rails_application = Rails.application
+      Rails.app_class = Rails.application = nil
+
       @prev_rails_env = ENV["RAILS_ENV"]
       ENV["RAILS_ENV"] = "development"
 
@@ -150,6 +154,8 @@ def build_app(options = {})
 
     def teardown_app
       ENV["RAILS_ENV"] = @prev_rails_env if @prev_rails_env
+      Rails.app_class = @prev_rails_app_class if @prev_rails_app_class
+      Rails.application = @prev_rails_application if @prev_rails_application
       FileUtils.rm_rf(tmp_path)
     end
 

railties/test/test_unit/reporter_test.rb

@@ -18,7 +18,7 @@ def woot; end
     record(failed_test)
     @reporter.report
 
-    assert_match %r{^bin/rails test .*test/test_unit/reporter_test\.rb:\d+$}, @output.string
+    assert_match %r{^#{test_run_command_regex} .*test/test_unit/reporter_test\.rb:\d+$}, @output.string
     assert_rerun_snippet_count 1
   end
 
@@ -64,15 +64,15 @@ def woot; end
     record(failed_test)
     @reporter.report
 
-    expect = %r{\AF\n\nFailure:\nTestUnitReporterTest::ExampleTest#woot \[[^\]]+\]:\nboo\n\nbin/rails test test/test_unit/reporter_test\.rb:\d+\n\n\z}
+    expect = %r{\AF\n\nFailure:\nTestUnitReporterTest::ExampleTest#woot \[[^\]]+\]:\nboo\n\n#{test_run_command_regex} test/test_unit/reporter_test\.rb:\d+\n\n\z}
     assert_match expect, @output.string
   end
 
   test "outputs errors inline" do
     record(errored_test)
     @reporter.report
 
-    expect = %r{\AE\n\nError:\nTestUnitReporterTest::ExampleTest#woot:\nArgumentError: wups\n    some_test.rb:4\n\nbin/rails test .*test/test_unit/reporter_test\.rb:\d+\n\n\z}
+    expect = %r{\AE\n\nError:\nTestUnitReporterTest::ExampleTest#woot:\nArgumentError: wups\n    some_test.rb:4\n\n#{test_run_command_regex} .*test/test_unit/reporter_test\.rb:\d+\n\n\z}
     assert_match expect, @output.string
   end
 
@@ -81,7 +81,7 @@ def woot; end
     record(skipped_test)
     @reporter.report
 
-    expect = %r{\ATestUnitReporterTest::ExampleTest#woot = 10\.00 s = S\n\n\nSkipped:\nTestUnitReporterTest::ExampleTest#woot \[[^\]]+\]:\nskipchurches, misstemples\n\nbin/rails test test/test_unit/reporter_test\.rb:\d+\n\n\z}
+    expect = %r{\ATestUnitReporterTest::ExampleTest#woot = 10\.00 s = S\n\n\nSkipped:\nTestUnitReporterTest::ExampleTest#woot \[[^\]]+\]:\nskipchurches, misstemples\n\n#{test_run_command_regex} test/test_unit/reporter_test\.rb:\d+\n\n\z}
     assert_match expect, @output.string
   end
 
@@ -152,7 +152,7 @@ def woot; end
       @reporter = Rails::TestUnitReporter.new @output, color: true, output_inline: true
       record(failed_test)
 
-      expected = %r{\e\[31mF\e\[0m\n\n\e\[31mFailure:\nTestUnitReporterTest::ExampleTest#woot \[test/test_unit/reporter_test.rb:\d+\]:\nboo\n\e\[0m\n\nbin/rails test .*test/test_unit/reporter_test.rb:\d+\n\n}
+      expected = %r{\e\[31mF\e\[0m\n\n\e\[31mFailure:\nTestUnitReporterTest::ExampleTest#woot \[test/test_unit/reporter_test.rb:\d+\]:\nboo\n\e\[0m\n\n#{test_run_command_regex} .*test/test_unit/reporter_test.rb:\d+\n\n}
       assert_match expected, @output.string
     end
   end
@@ -174,7 +174,7 @@ def record(test_result)
     end
 
     def assert_rerun_snippet_count(snippet_count)
-      assert_equal snippet_count, @output.string.scan(%r{^bin/rails test }).size
+      assert_equal snippet_count, @output.string.scan(%r{^#{test_run_command_regex} }).size
     end
 
     def failed_test
@@ -210,4 +210,8 @@ def skipped_test
       st.time = 10
       st
     end
+
+    def test_run_command_regex
+      %r{bin/rails test|bin/test}
+    end
 end