test: extract setup and teardown in ForkTracker tests

and backfill coverage for deregistering callbacks.

activesupport/test/fork_tracker_test.rb

@@ -3,164 +3,114 @@
 require_relative "abstract_unit"
 
 class ForkTrackerTest < ActiveSupport::TestCase
-  def test_object_fork
-    read, write = IO.pipe
-    called = false
+  def setup
+    super
+
+    @read, @write = IO.pipe
+    @called = false
 
-    handler = ActiveSupport::ForkTracker.after_fork do
-      called = true
-      write.write "forked"
+    @handler = ActiveSupport::ForkTracker.after_fork do
+      @called = true
+      @write.write "forked"
     end
+  end
 
+  def teardown
+    ActiveSupport::ForkTracker.unregister(@handler)
+
+    super
+  end
+
+  def test_object_fork
     assert_not respond_to?(:fork)
     pid = fork do
-      read.close
-      write.close
+      @read.close
+      @write.close
       exit!
     end
 
-    write.close
+    @write.close
 
     Process.waitpid(pid)
-    assert_equal "forked", read.read
-    read.close
+    assert_equal "forked", @read.read
+    @read.close
 
-    assert_not called
-  ensure
-    ActiveSupport::ForkTracker.unregister(handler)
+    assert_not @called
   end
 
   def test_object_fork_without_block
-    read, write = IO.pipe
-    called = false
-
-    handler = ActiveSupport::ForkTracker.after_fork do
-      called = true
-      write.write "forked"
-    end
-
     if pid = fork
-      write.close
+      @write.close
       Process.waitpid(pid)
-      assert_equal "forked", read.read
-      read.close
-      assert_not called
+      assert_equal "forked", @read.read
+      @read.close
+      assert_not @called
     else
-      read.close
-      write.close
+      @read.close
+      @write.close
       exit!
     end
-  ensure
-    ActiveSupport::ForkTracker.unregister(handler)
   end
 
   def test_process_fork
-    read, write = IO.pipe
-    called = false
-
-    handler = ActiveSupport::ForkTracker.after_fork do
-      called = true
-      write.write "forked"
-    end
-
     pid = Process.fork do
-      read.close
-      write.close
+      @read.close
+      @write.close
       exit!
     end
 
-    write.close
+    @write.close
 
     Process.waitpid(pid)
-    assert_equal "forked", read.read
-    read.close
-    assert_not called
-  ensure
-    ActiveSupport::ForkTracker.unregister(handler)
+    assert_equal "forked", @read.read
+    @read.close
+    assert_not @called
   end
 
   def test_process_fork_without_block
-    read, write = IO.pipe
-    called = false
-
-    handler = ActiveSupport::ForkTracker.after_fork do
-      called = true
-      write.write "forked"
-    end
-
     if pid = Process.fork
-      write.close
+      @write.close
       Process.waitpid(pid)
-      assert_equal "forked", read.read
-      read.close
-      assert_not called
+      assert_equal "forked", @read.read
+      @read.close
+      assert_not @called
     else
-      read.close
-      write.close
+      @read.close
+      @write.close
       exit!
     end
-  ensure
-    ActiveSupport::ForkTracker.unregister(handler)
   end
 
   def test_kernel_fork
-    read, write = IO.pipe
-    called = false
-
-    handler = ActiveSupport::ForkTracker.after_fork do
-      called = true
-      write.write "forked"
-    end
-
     pid = Kernel.fork do
-      read.close
-      write.close
+      @read.close
+      @write.close
       exit!
     end
 
-    write.close
+    @write.close
 
     Process.waitpid(pid)
-    assert_equal "forked", read.read
-    read.close
-    assert_not called
-  ensure
-    ActiveSupport::ForkTracker.unregister(handler)
+    assert_equal "forked", @read.read
+    @read.close
+    assert_not @called
   end
 
   def test_kernel_fork_without_block
-    read, write = IO.pipe
-    called = false
-
-    handler = ActiveSupport::ForkTracker.after_fork do
-      called = true
-      write.write "forked"
-    end
-
     if pid = Kernel.fork
-      write.close
+      @write.close
       Process.waitpid(pid)
-      assert_equal "forked", read.read
-      read.close
-      assert_not called
+      assert_equal "forked", @read.read
+      @read.close
+      assert_not @called
     else
-      read.close
-      write.close
+      @read.close
+      @write.close
       exit!
     end
-  ensure
-    ActiveSupport::ForkTracker.unregister(handler)
   end
 
   def test_basic_object_with_kernel_fork
-    read, write = IO.pipe
-    called = false
-
-    handler = ActiveSupport::ForkTracker.after_fork do
-      called = true
-      write.write "forked"
-    end
-
     klass = Class.new(BasicObject) do
       include ::Kernel
       def fark(&block)
@@ -171,19 +121,33 @@ def fark(&block)
     object = klass.new
     assert_not object.respond_to?(:fork)
     pid = object.fark do
-      read.close
-      write.close
+      @read.close
+      @write.close
       exit!
     end
 
-    write.close
+    @write.close
 
     Process.waitpid(pid)
-    assert_equal "forked", read.read
-    read.close
+    assert_equal "forked", @read.read
+    @read.close
 
-    assert_not called
-  ensure
-    ActiveSupport::ForkTracker.unregister(handler)
+    assert_not @called
+  end
+
+  def test_unregister_callback
+    ActiveSupport::ForkTracker.unregister(@handler)
+
+    if pid = Process.fork
+      @write.close
+      Process.waitpid(pid)
+      assert_equal "", @read.read
+      @read.close
+      assert_not @called
+    else
+      @read.close
+      @write.close
+      exit!
+    end
   end
 end if Process.respond_to?(:fork)