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.

7 files changed, 50 insertions, 72 deletions

diff --git a/activejob/Rakefile b/activejob/Rakefile
index 2b9f89853f..037e84fca9 100644
--- a/activejob/Rakefile
+++ b/activejob/Rakefile
@@ -68,11 +68,9 @@ def run_without_aborting(tasks)
   errors = []
 
   tasks.each do |task|
-    begin
-      Rake::Task[task].invoke
-    rescue Exception
-      errors << task
-    end
+    Rake::Task[task].invoke
+  rescue Exception
+    errors << task
   end
 
   abort "Errors running #{errors.join(', ')}" if errors.any?
diff --git a/activejob/test/cases/callbacks_test.rb b/activejob/test/cases/callbacks_test.rb
index 267d58a7c8..895edb34a5 100644
--- a/activejob/test/cases/callbacks_test.rb
+++ b/activejob/test/cases/callbacks_test.rb
@@ -25,26 +25,22 @@ class CallbacksTest < ActiveSupport::TestCase
   end
 
   test "#enqueue returns false when before_enqueue aborts callback chain and return_false_on_aborted_enqueue = true" do
-    begin
-      prev = ActiveJob::Base.return_false_on_aborted_enqueue
-      ActiveJob::Base.return_false_on_aborted_enqueue = true
-      assert_equal false, AbortBeforeEnqueueJob.new.enqueue
-    ensure
-      ActiveJob::Base.return_false_on_aborted_enqueue = prev
-    end
+    prev = ActiveJob::Base.return_false_on_aborted_enqueue
+    ActiveJob::Base.return_false_on_aborted_enqueue = true
+    assert_equal false, AbortBeforeEnqueueJob.new.enqueue
+  ensure
+    ActiveJob::Base.return_false_on_aborted_enqueue = prev
   end
 
   test "#enqueue returns self when before_enqueue aborts callback chain and return_false_on_aborted_enqueue = false" do
-    begin
-      prev = ActiveJob::Base.return_false_on_aborted_enqueue
-      ActiveJob::Base.return_false_on_aborted_enqueue = false
-      job = AbortBeforeEnqueueJob.new
-      assert_deprecated do
-        assert_equal job, job.enqueue
-      end
-    ensure
-      ActiveJob::Base.return_false_on_aborted_enqueue = prev
+    prev = ActiveJob::Base.return_false_on_aborted_enqueue
+    ActiveJob::Base.return_false_on_aborted_enqueue = false
+    job = AbortBeforeEnqueueJob.new
+    assert_deprecated do
+      assert_equal job, job.enqueue
     end
+  ensure
+    ActiveJob::Base.return_false_on_aborted_enqueue = prev
   end
 
   test "#enqueue returns self when the job was enqueued" do
diff --git a/activejob/test/cases/exceptions_test.rb b/activejob/test/cases/exceptions_test.rb
index b5328b8d6a..67327e0bbd 100644
--- a/activejob/test/cases/exceptions_test.rb
+++ b/activejob/test/cases/exceptions_test.rb
@@ -54,23 +54,19 @@ class ExceptionsTest < ActiveJob::TestCase
 
   test "failed retry job when exception kept occurring against defaults" do
     perform_enqueued_jobs do
-      begin
-        RetryJob.perform_later "DefaultsError", 6
-        assert_equal "Raised DefaultsError for the 5th time", JobBuffer.last_value
-      rescue DefaultsError
-        pass
-      end
+      RetryJob.perform_later "DefaultsError", 6
+      assert_equal "Raised DefaultsError for the 5th time", JobBuffer.last_value
+    rescue DefaultsError
+      pass
     end
   end
 
   test "failed retry job when exception kept occurring against higher limit" do
     perform_enqueued_jobs do
-      begin
-        RetryJob.perform_later "ShortWaitTenAttemptsError", 11
-        assert_equal "Raised ShortWaitTenAttemptsError for the 10th time", JobBuffer.last_value
-      rescue ShortWaitTenAttemptsError
-        pass
-      end
+      RetryJob.perform_later "ShortWaitTenAttemptsError", 11
+      assert_equal "Raised ShortWaitTenAttemptsError for the 10th time", JobBuffer.last_value
+    rescue ShortWaitTenAttemptsError
+      pass
     end
   end
 
diff --git a/activejob/test/cases/logging_test.rb b/activejob/test/cases/logging_test.rb
index 48ef39aaca..6154ba301d 100644
--- a/activejob/test/cases/logging_test.rb
+++ b/activejob/test/cases/logging_test.rb
@@ -187,11 +187,9 @@ class LoggingTest < ActiveSupport::TestCase
 
   def test_retry_stopped_logging_without_block
     perform_enqueued_jobs do
-      begin
-        RetryJob.perform_later "DefaultsError", 6
-      rescue DefaultsError
-        assert_match(/Stopped retrying RetryJob due to a DefaultsError, which reoccurred on \d+ attempts\./, @logger.messages)
-      end
+      RetryJob.perform_later "DefaultsError", 6
+    rescue DefaultsError
+      assert_match(/Stopped retrying RetryJob due to a DefaultsError, which reoccurred on \d+ attempts\./, @logger.messages)
     end
   end
 
diff --git a/activejob/test/cases/queuing_test.rb b/activejob/test/cases/queuing_test.rb
index 0e843b7215..e7bad83400 100644
--- a/activejob/test/cases/queuing_test.rb
+++ b/activejob/test/cases/queuing_test.rb
@@ -20,12 +20,10 @@ class QueuingTest < ActiveSupport::TestCase
   end
 
   test "run queued job later" do
-    begin
-      result = HelloJob.set(wait_until: 1.second.ago).perform_later "Jamie"
-      assert result
-    rescue NotImplementedError
-      skip
-    end
+    result = HelloJob.set(wait_until: 1.second.ago).perform_later "Jamie"
+    assert result
+  rescue NotImplementedError
+    skip
   end
 
   test "job returned by enqueue has the arguments available" do
@@ -34,11 +32,9 @@ class QueuingTest < ActiveSupport::TestCase
   end
 
   test "job returned by perform_at has the timestamp available" do
-    begin
-      job = HelloJob.set(wait_until: Time.utc(2014, 1, 1)).perform_later
-      assert_equal Time.utc(2014, 1, 1).to_f, job.scheduled_at
-    rescue NotImplementedError
-      skip
-    end
+    job = HelloJob.set(wait_until: Time.utc(2014, 1, 1)).perform_later
+    assert_equal Time.utc(2014, 1, 1).to_f, job.scheduled_at
+  rescue NotImplementedError
+    skip
   end
 end
diff --git a/activejob/test/integration/queuing_test.rb b/activejob/test/integration/queuing_test.rb
index 96253773c7..1fa68a8ad5 100644
--- a/activejob/test/integration/queuing_test.rb
+++ b/activejob/test/integration/queuing_test.rb
@@ -60,25 +60,21 @@ class QueuingTest < ActiveSupport::TestCase
   end
 
   test "should not run job enqueued in the future" do
-    begin
-      TestJob.set(wait: 10.minutes).perform_later @id
-      wait_for_jobs_to_finish_for(5.seconds)
-      assert_not job_executed
-    rescue NotImplementedError
-      skip
-    end
+    TestJob.set(wait: 10.minutes).perform_later @id
+    wait_for_jobs_to_finish_for(5.seconds)
+    assert_not job_executed
+  rescue NotImplementedError
+    skip
   end
 
   test "should run job enqueued in the future at the specified time" do
-    begin
-      TestJob.set(wait: 5.seconds).perform_later @id
-      wait_for_jobs_to_finish_for(2.seconds)
-      assert_not job_executed
-      wait_for_jobs_to_finish_for(10.seconds)
-      assert job_executed
-    rescue NotImplementedError
-      skip
-    end
+    TestJob.set(wait: 5.seconds).perform_later @id
+    wait_for_jobs_to_finish_for(2.seconds)
+    assert_not job_executed
+    wait_for_jobs_to_finish_for(10.seconds)
+    assert job_executed
+  rescue NotImplementedError
+    skip
   end
 
   test "should supply a provider_job_id when available for immediate jobs" do
diff --git a/activejob/test/support/integration/test_case_helpers.rb b/activejob/test/support/integration/test_case_helpers.rb
index 3d9b265b66..973ee07764 100644
--- a/activejob/test/support/integration/test_case_helpers.rb
+++ b/activejob/test/support/integration/test_case_helpers.rb
@@ -33,14 +33,12 @@ module TestCaseHelpers
     end
 
     def wait_for_jobs_to_finish_for(seconds = 60)
-      begin
-        Timeout.timeout(seconds) do
-          while !job_executed do
-            sleep 0.25
-          end
+      Timeout.timeout(seconds) do
+        while !job_executed do
+          sleep 0.25
         end
-      rescue Timeout::Error
       end
+    rescue Timeout::Error
     end
 
     def job_file(id)