Remove unneeded reliance on super -> method_missing quirk

activesupport/lib/active_support/duration.rb

@@ -36,7 +36,7 @@ def -@ #:nodoc:
     end
 
     def is_a?(klass) #:nodoc:
-      klass == Duration || super
+      Duration == klass || value.is_a?(klass)
     end
 
     # Returns true if <tt>other</tt> is also a Duration instance with the
@@ -50,7 +50,9 @@ def ==(other)
     end
 
     def self.===(other) #:nodoc:
-      other.is_a?(Duration) rescue super
+      other.is_a?(Duration)
+    rescue NoMethodError
+      false
     end
 
     # Calculates a new Time or Date that is as far in the future

activesupport/test/core_ext/duration_test.rb

@@ -2,6 +2,31 @@
 require 'active_support/time'
 
 class DurationTest < ActiveSupport::TestCase
+  def test_is_a
+    d = 1.day
+    assert d.is_a?(ActiveSupport::Duration)
+    assert d.is_a?(Numeric)
+    assert d.is_a?(Fixnum)
+    assert !d.is_a?(Hash)
+
+    k = Class.new
+    class << k; undef_method :== end
+    assert !d.is_a?(k)
+  end
+
+  def test_threequals
+    assert ActiveSupport::Duration === 1.day
+    assert !(ActiveSupport::Duration === 1.day.to_i)
+    assert !(ActiveSupport::Duration === 'foo')
+    assert !(ActiveSupport::Duration === ActiveSupport::BasicObject.new)
+  end
+
+  def test_equals
+    assert 1.day == 1.day
+    assert 1.day == 1.day.to_i
+    assert !(1.day == 'foo')
+  end
+
   def test_inspect
     assert_equal '0 seconds',                       0.seconds.inspect
     assert_equal '1 month',                         1.month.inspect