1 files changed, 115 insertions, 0 deletions
diff --git a/actionpack/test/dispatch/middleware_stack_test.rb b/actionpack/test/dispatch/middleware_stack_test.rb
new file mode 100644
index 0000000000..5f43e5a3c5
--- /dev/null
+++ b/actionpack/test/dispatch/middleware_stack_test.rb
@@ -0,0 +1,115 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class MiddlewareStackTest < ActiveSupport::TestCase
+  class FooMiddleware; end
+  class BarMiddleware; end
+  class BazMiddleware; end
+  class HiyaMiddleware; end
+  class BlockMiddleware
+    attr_reader :block
+    def initialize(&block)
+      @block = block
+    end
+  end
+
+  def setup
+    @stack = ActionDispatch::MiddlewareStack.new
+    @stack.use FooMiddleware
+    @stack.use BarMiddleware
+  end
+
+  def test_delete_works
+    assert_difference "@stack.size", -1 do
+      @stack.delete FooMiddleware
+    end
+  end
+
+  test "use should push middleware as class onto the stack" do
+    assert_difference "@stack.size" do
+      @stack.use BazMiddleware
+    end
+    assert_equal BazMiddleware, @stack.last.klass
+  end
+
+  test "use should push middleware class with arguments onto the stack" do
+    assert_difference "@stack.size" do
+      @stack.use BazMiddleware, true, foo: "bar"
+    end
+    assert_equal BazMiddleware, @stack.last.klass
+    assert_equal([true, { foo: "bar" }], @stack.last.args)
+  end
+
+  test "use should push middleware class with block arguments onto the stack" do
+    proc = Proc.new { }
+    assert_difference "@stack.size" do
+      @stack.use(BlockMiddleware, &proc)
+    end
+    assert_equal BlockMiddleware, @stack.last.klass
+    assert_equal proc, @stack.last.block
+  end
+
+  test "insert inserts middleware at the integer index" do
+    @stack.insert(1, BazMiddleware)
+    assert_equal BazMiddleware, @stack[1].klass
+  end
+
+  test "insert_after inserts middleware after the integer index" do
+    @stack.insert_after(1, BazMiddleware)
+    assert_equal BazMiddleware, @stack[2].klass
+  end
+
+  test "insert_before inserts middleware before another middleware class" do
+    @stack.insert_before(BarMiddleware, BazMiddleware)
+    assert_equal BazMiddleware, @stack[1].klass
+  end
+
+  test "insert_after inserts middleware after another middleware class" do
+    @stack.insert_after(BarMiddleware, BazMiddleware)
+    assert_equal BazMiddleware, @stack[2].klass
+  end
+
+  test "swaps one middleware out for another" do
+    assert_equal FooMiddleware, @stack[0].klass
+    @stack.swap(FooMiddleware, BazMiddleware)
+    assert_equal BazMiddleware, @stack[0].klass
+  end
+
+  test "swaps one middleware out for same middleware class" do
+    assert_equal FooMiddleware, @stack[0].klass
+    @stack.swap(FooMiddleware, FooMiddleware, Proc.new { |env| [500, {}, ["error!"]] })
+    assert_equal FooMiddleware, @stack[0].klass
+  end
+
+  test "unshift adds a new middleware at the beginning of the stack" do
+    @stack.unshift MiddlewareStackTest::BazMiddleware
+    assert_equal BazMiddleware, @stack.first.klass
+  end
+
+  test "raise an error on invalid index" do
+    assert_raise RuntimeError do
+      @stack.insert(HiyaMiddleware, BazMiddleware)
+    end
+
+    assert_raise RuntimeError do
+      @stack.insert_after(HiyaMiddleware, BazMiddleware)
+    end
+  end
+
+  test "can check if Middleware are equal - Class" do
+    assert_equal @stack.last, BarMiddleware
+  end
+
+  test "includes a class" do
+    assert_equal true, @stack.include?(BarMiddleware)
+  end
+
+  test "can check if Middleware are equal - Middleware" do
+    assert_equal @stack.last, @stack.last
+  end
+
+  test "includes a middleware" do
+    assert_equal true, @stack.include?(ActionDispatch::MiddlewareStack::Middleware.new(BarMiddleware, nil, nil))
+  end
+end