1 files changed, 82 insertions, 0 deletions
diff --git a/spec/ruby/core/array/each_spec.rb b/spec/ruby/core/array/each_spec.rb
new file mode 100644
index 0000000000..f4b5b758d0
--- /dev/null
+++ b/spec/ruby/core/array/each_spec.rb
@@ -0,0 +1,82 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+require_relative 'shared/enumeratorize'
+require_relative 'shared/iterable_and_tolerating_size_increasing'
+require_relative '../enumerable/shared/enumeratorized'
+
+# Mutating the array while it is being iterated is discouraged as it can result in confusing behavior.
+# Yet a Ruby implementation must not crash in such a case, and following the simple CRuby behavior makes sense.
+# CRuby simply reads the array storage and checks the size for every iteration;
+# like `i = 0; while i < size; yield self[i]; i += 1; end`
+
+describe "Array#each" do
+  it "yields each element to the block" do
+    a = []
+    x = [1, 2, 3]
+    x.each { |item| a << item }.should equal(x)
+    a.should == [1, 2, 3]
+  end
+
+  it "yields each element to the block even if the array is changed during iteration" do
+    a = [1, 2, 3, 4, 5]
+    iterated = []
+    a.each { |x| iterated << x; a << x+5 if x.even? }
+    iterated.should == [1, 2, 3, 4, 5, 7, 9]
+  end
+
+  it "yields only elements that are still in the array" do
+    a = [0, 1, 2, 3, 4]
+    iterated = []
+    a.each { |x| iterated << x; a.pop if x.even? }
+    iterated.should == [0, 1, 2]
+  end
+
+  it "yields elements based on an internal index" do
+    a = [0, 1, 2, 3, 4]
+    iterated = []
+    a.each { |x| iterated << x; a.shift if x.even? }
+    iterated.should == [0, 2, 4]
+  end
+
+  it "yields the same element multiple times if inserting while iterating" do
+    a = [1, 2]
+    iterated = []
+    a.each { |x| iterated << x; a.unshift(0) if a.size == 2 }
+    iterated.should == [1, 1, 2]
+  end
+
+  it "yields each element to a block that takes multiple arguments" do
+    a = [[1, 2], :a, [3, 4]]
+    b = []
+
+    a.each { |x, y| b << x }
+    b.should == [1, :a, 3]
+
+    b = []
+    a.each { |x, y| b << y }
+    b.should == [2, nil, 4]
+  end
+
+  it "yields elements added to the end of the array by the block" do
+    a = [2]
+    iterated = []
+    a.each { |x| iterated << x; x.times { a << 0 } }
+
+    iterated.should == [2, 0, 0]
+  end
+
+  it "does not yield elements deleted from the end of the array" do
+    a = [2, 3, 1]
+    iterated = []
+    a.each { |x| iterated << x; a.delete_at(2) if x == 3 }
+
+    iterated.should == [2, 3]
+  end
+
+  it_behaves_like :enumeratorize, :each
+  it_behaves_like :enumeratorized_with_origin_size, :each, [1,2,3]
+end
+
+describe "Array#each" do
+  it_behaves_like :array_iterable_and_tolerating_size_increasing, :each
+end