1 files changed, 37 insertions, 0 deletions
diff --git a/spec/ruby/core/array/shared/index.rb b/spec/ruby/core/array/shared/index.rb
new file mode 100644
index 0000000000..a9896554f2
--- /dev/null
+++ b/spec/ruby/core/array/shared/index.rb
@@ -0,0 +1,37 @@
+describe :array_index, shared: true do
+  it "returns the index of the first element == to object" do
+    x = mock('3')
+    def x.==(obj) 3 == obj; end
+
+    [2, x, 3, 1, 3, 1].send(@method, 3).should == 1
+    [2, 3.0, 3, x, 1, 3, 1].send(@method, x).should == 1
+  end
+
+  it "returns 0 if first element == to object" do
+    [2, 1, 3, 2, 5].send(@method, 2).should == 0
+  end
+
+  it "returns size-1 if only last element == to object" do
+    [2, 1, 3, 1, 5].send(@method, 5).should == 4
+  end
+
+  it "returns nil if no element == to object" do
+    [2, 1, 1, 1, 1].send(@method, 3).should == nil
+  end
+
+  it "accepts a block instead of an argument" do
+    [4, 2, 1, 5, 1, 3].send(@method) {|x| x < 2}.should == 2
+  end
+
+  it "ignores the block if there is an argument" do
+    -> {
+      [4, 2, 1, 5, 1, 3].send(@method, 5) {|x| x < 2}.should == 3
+    }.should complain(/given block not used/)
+  end
+
+  describe "given no argument and no block" do
+    it "produces an Enumerator" do
+      [].send(@method).should be_an_instance_of(Enumerator)
+    end
+  end
+end