1 files changed, 103 insertions, 0 deletions
diff --git a/spec/ruby/core/range/reverse_each_spec.rb b/spec/ruby/core/range/reverse_each_spec.rb
new file mode 100644
index 0000000000..56390cc0da
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+++ b/spec/ruby/core/range/reverse_each_spec.rb
@@ -0,0 +1,103 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "3.3" do
+  describe "Range#reverse_each" do
+    it "traverses the Range in reverse order and passes each element to block" do
+      a = []
+      (1..3).reverse_each { |i| a << i }
+      a.should == [3, 2, 1]
+
+      a = []
+      (1...3).reverse_each { |i| a << i }
+      a.should == [2, 1]
+    end
+
+    it "returns self" do
+      r = (1..3)
+      r.reverse_each { |x| }.should equal(r)
+    end
+
+    it "returns an Enumerator if no block given" do
+      enum = (1..3).reverse_each
+      enum.should be_an_instance_of(Enumerator)
+      enum.to_a.should == [3, 2, 1]
+    end
+
+    it "raises a TypeError for endless Ranges of Integers" do
+      -> {
+        (1..).reverse_each.take(3)
+      }.should raise_error(TypeError, "can't iterate from NilClass")
+    end
+
+    it "raises a TypeError for endless Ranges of non-Integers" do
+      -> {
+        ("a"..).reverse_each.take(3)
+      }.should raise_error(TypeError, "can't iterate from NilClass")
+    end
+
+    context "Integer boundaries" do
+      it "supports beginningless Ranges" do
+        (..5).reverse_each.take(3).should == [5, 4, 3]
+      end
+    end
+
+    context "non-Integer boundaries" do
+      it "uses #succ to iterate a Range of non-Integer elements" do
+        y = mock('y')
+        x = mock('x')
+
+        x.should_receive(:succ).any_number_of_times.and_return(y)
+        x.should_receive(:<=>).with(y).any_number_of_times.and_return(-1)
+        x.should_receive(:<=>).with(x).any_number_of_times.and_return(0)
+        y.should_receive(:<=>).with(x).any_number_of_times.and_return(1)
+        y.should_receive(:<=>).with(y).any_number_of_times.and_return(0)
+
+        a = []
+        (x..y).each { |i| a << i }
+        a.should == [x, y]
+      end
+
+      it "uses #succ to iterate a Range of Strings" do
+        a = []
+        ('A'..'D').reverse_each { |i| a << i }
+        a.should == ['D','C','B','A']
+      end
+
+      it "uses #succ to iterate a Range of Symbols" do
+        a = []
+        (:A..:D).reverse_each { |i| a << i }
+        a.should == [:D, :C, :B, :A]
+      end
+
+      it "raises a TypeError when `begin` value does not respond to #succ" do
+        -> { (Time.now..Time.now).reverse_each { |x| x } }.should raise_error(TypeError, /can't iterate from Time/)
+        -> { (//..//).reverse_each { |x| x } }.should raise_error(TypeError, /can't iterate from Regexp/)
+        -> { ([]..[]).reverse_each { |x| x } }.should raise_error(TypeError, /can't iterate from Array/)
+      end
+
+      it "does not support beginningless Ranges" do
+        -> {
+          (..'a').reverse_each { |x| x }
+        }.should raise_error(TypeError, /can't iterate from NilClass/)
+      end
+    end
+
+    context "when no block is given" do
+      describe "returned Enumerator size" do
+        it "returns the Range size when Range size is finite" do
+          (1..3).reverse_each.size.should == 3
+        end
+
+        ruby_bug "#20936", "3.4"..."4.0" do
+          it "returns Infinity when Range size is infinite" do
+            (..3).reverse_each.size.should == Float::INFINITY
+          end
+        end
+
+        it "returns nil when Range size is unknown" do
+          ('a'..'z').reverse_each.size.should == nil
+        end
+      end
+    end
+  end
+end