1 files changed, 99 insertions, 0 deletions
diff --git a/activesupport/test/reloader_test.rb b/activesupport/test/reloader_test.rb
new file mode 100644
index 0000000000..1b7cc253d9
--- /dev/null
+++ b/activesupport/test/reloader_test.rb
@@ -0,0 +1,99 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ReloaderTest < ActiveSupport::TestCase
+  def test_prepare_callback
+    prepared = completed = false
+    reloader.to_prepare { prepared = true }
+    reloader.to_complete { completed = true }
+
+    assert_not prepared
+    assert_not completed
+    reloader.prepare!
+    assert prepared
+    assert_not completed
+
+    prepared = false
+    reloader.wrap do
+      assert prepared
+      prepared = false
+    end
+    assert_not prepared
+  end
+
+  def test_prepend_prepare_callback
+    i = 10
+    reloader.to_prepare { i += 1 }
+    reloader.to_prepare(prepend: true) { i = 0 }
+
+    reloader.prepare!
+    assert_equal 1, i
+  end
+
+  def test_only_run_when_check_passes
+    r = new_reloader { true }
+    invoked = false
+    r.to_run { invoked = true }
+    r.wrap { }
+    assert invoked
+
+    r = new_reloader { false }
+    invoked = false
+    r.to_run { invoked = true }
+    r.wrap { }
+    assert_not invoked
+  end
+
+  def test_full_reload_sequence
+    called = []
+    reloader.to_prepare { called << :prepare }
+    reloader.to_run { called << :reloader_run }
+    reloader.to_complete { called << :reloader_complete }
+    reloader.executor.to_run { called << :executor_run }
+    reloader.executor.to_complete { called << :executor_complete }
+
+    reloader.wrap { }
+    assert_equal [:executor_run, :reloader_run, :prepare, :reloader_complete, :executor_complete], called
+
+    called = []
+    reloader.reload!
+    assert_equal [:executor_run, :reloader_run, :prepare, :reloader_complete, :executor_complete, :prepare], called
+
+    reloader.check = lambda { false }
+
+    called = []
+    reloader.wrap { }
+    assert_equal [:executor_run, :executor_complete], called
+
+    called = []
+    reloader.reload!
+    assert_equal [:executor_run, :reloader_run, :prepare, :reloader_complete, :executor_complete, :prepare], called
+  end
+
+  def test_class_unload_block
+    called = []
+    reloader.before_class_unload { called << :before_unload }
+    reloader.after_class_unload { called << :after_unload }
+    reloader.to_run do
+      class_unload! do
+        called << :unload
+      end
+    end
+    reloader.wrap { called << :body }
+
+    assert_equal [:before_unload, :unload, :after_unload, :body], called
+  end
+
+  private
+    def new_reloader(&check)
+      Class.new(ActiveSupport::Reloader).tap do |r|
+        r.check = check
+        r.executor = Class.new(ActiveSupport::Executor)
+      end
+    end
+
+    def reloader
+      @reloader ||= new_reloader { true }
+    end
+end