Enable `Style/RedundantBegin` cop to avoid newly adding redundant begin block

Currently we sometimes find a redundant begin block in code review
(e.g. https://github.com/rails/rails/pull/33604#discussion_r209784205).

I'd like to enable `Style/RedundantBegin` cop to avoid that, since
rescue/else/ensure are allowed inside do/end blocks in Ruby 2.5
(https://bugs.ruby-lang.org/issues/12906), so we'd probably meets with
that situation than before.

3 files changed, 38 insertions, 50 deletions

diff --git a/actionpack/test/controller/action_pack_assertions_test.rb b/actionpack/test/controller/action_pack_assertions_test.rb
index 763df3a776..ecb8c37e6b 100644
--- a/actionpack/test/controller/action_pack_assertions_test.rb
+++ b/actionpack/test/controller/action_pack_assertions_test.rb
@@ -276,16 +276,14 @@ class ActionPackAssertionsControllerTest < ActionController::TestCase
   end
 
   def test_assert_redirect_failure_message_with_protocol_relative_url
-    begin
-      process :redirect_external_protocol_relative
-      assert_redirected_to "/foo"
-    rescue ActiveSupport::TestCase::Assertion => ex
-      assert_no_match(
-        /#{request.protocol}#{request.host}\/\/www.rubyonrails.org/,
-        ex.message,
-        "protocol relative url was incorrectly normalized"
-      )
-    end
+    process :redirect_external_protocol_relative
+    assert_redirected_to "/foo"
+  rescue ActiveSupport::TestCase::Assertion => ex
+    assert_no_match(
+      /#{request.protocol}#{request.host}\/\/www.rubyonrails.org/,
+      ex.message,
+      "protocol relative url was incorrectly normalized"
+    )
   end
 
   def test_template_objects_exist
diff --git a/actionpack/test/controller/filters_test.rb b/actionpack/test/controller/filters_test.rb
index 8e117528e2..104c9eeade 100644
--- a/actionpack/test/controller/filters_test.rb
+++ b/actionpack/test/controller/filters_test.rb
@@ -1000,16 +1000,12 @@ class YieldingAroundFiltersTest < ActionController::TestCase
   def test_nested_actions
     controller = ControllerWithNestedFilters
     assert_nothing_raised do
-      begin
-        test_process(controller, "raises_both")
-      rescue Before, After
-      end
+      test_process(controller, "raises_both")
+    rescue Before, After
     end
     assert_raise Before do
-      begin
-        test_process(controller, "raises_both")
-      rescue After
-      end
+      test_process(controller, "raises_both")
+    rescue After
     end
   end
 
diff --git a/actionpack/test/controller/parameters/parameters_permit_test.rb b/actionpack/test/controller/parameters/parameters_permit_test.rb
index d2fa0aa16e..fbfe24059b 100644
--- a/actionpack/test/controller/parameters/parameters_permit_test.rb
+++ b/actionpack/test/controller/parameters/parameters_permit_test.rb
@@ -365,17 +365,15 @@ class ParametersPermitTest < ActiveSupport::TestCase
   end
 
   test "permitted takes a default value when Parameters.permit_all_parameters is set" do
-    begin
-      ActionController::Parameters.permit_all_parameters = true
-      params = ActionController::Parameters.new(person: {
-        age: "32", name: { first: "David", last: "Heinemeier Hansson" }
-      })
-
-      assert_predicate params.slice(:person), :permitted?
-      assert_predicate params[:person][:name], :permitted?
-    ensure
-      ActionController::Parameters.permit_all_parameters = false
-    end
+    ActionController::Parameters.permit_all_parameters = true
+    params = ActionController::Parameters.new(person: {
+      age: "32", name: { first: "David", last: "Heinemeier Hansson" }
+    })
+
+    assert_predicate params.slice(:person), :permitted?
+    assert_predicate params[:person][:name], :permitted?
+  ensure
+    ActionController::Parameters.permit_all_parameters = false
   end
 
   test "permitting parameters as an array" do
@@ -396,16 +394,14 @@ class ParametersPermitTest < ActiveSupport::TestCase
   end
 
   test "to_h returns converted hash when .permit_all_parameters is set" do
-    begin
-      ActionController::Parameters.permit_all_parameters = true
-      params = ActionController::Parameters.new(crab: "Senjougahara Hitagi")
-
-      assert_instance_of ActiveSupport::HashWithIndifferentAccess, params.to_h
-      assert_not_kind_of ActionController::Parameters, params.to_h
-      assert_equal({ "crab" => "Senjougahara Hitagi" }, params.to_h)
-    ensure
-      ActionController::Parameters.permit_all_parameters = false
-    end
+    ActionController::Parameters.permit_all_parameters = true
+    params = ActionController::Parameters.new(crab: "Senjougahara Hitagi")
+
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, params.to_h
+    assert_not_kind_of ActionController::Parameters, params.to_h
+    assert_equal({ "crab" => "Senjougahara Hitagi" }, params.to_h)
+  ensure
+    ActionController::Parameters.permit_all_parameters = false
   end
 
   test "to_hash raises UnfilteredParameters on unfiltered params" do
@@ -429,17 +425,15 @@ class ParametersPermitTest < ActiveSupport::TestCase
   end
 
   test "to_hash returns converted hash when .permit_all_parameters is set" do
-    begin
-      ActionController::Parameters.permit_all_parameters = true
-      params = ActionController::Parameters.new(crab: "Senjougahara Hitagi")
-
-      assert_instance_of Hash, params.to_hash
-      assert_not_kind_of ActionController::Parameters, params.to_hash
-      assert_equal({ "crab" => "Senjougahara Hitagi" }, params.to_hash)
-      assert_equal({ "crab" => "Senjougahara Hitagi" }, params)
-    ensure
-      ActionController::Parameters.permit_all_parameters = false
-    end
+    ActionController::Parameters.permit_all_parameters = true
+    params = ActionController::Parameters.new(crab: "Senjougahara Hitagi")
+
+    assert_instance_of Hash, params.to_hash
+    assert_not_kind_of ActionController::Parameters, params.to_hash
+    assert_equal({ "crab" => "Senjougahara Hitagi" }, params.to_hash)
+    assert_equal({ "crab" => "Senjougahara Hitagi" }, params)
+  ensure
+    ActionController::Parameters.permit_all_parameters = false
   end
 
   test "to_unsafe_h returns unfiltered params" do