1 files changed, 56 insertions, 0 deletions
diff --git a/spec/ruby/core/array/at_spec.rb b/spec/ruby/core/array/at_spec.rb
new file mode 100644
index 0000000000..8bc789fef7
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+++ b/spec/ruby/core/array/at_spec.rb
@@ -0,0 +1,56 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "Array#at" do
+  it "returns the (n+1)'th element for the passed index n" do
+    a = [1, 2, 3, 4, 5, 6]
+    a.at(0).should == 1
+    a.at(1).should == 2
+    a.at(5).should == 6
+  end
+
+  it "returns nil if the given index is greater than or equal to the array's length" do
+    a = [1, 2, 3, 4, 5, 6]
+    a.at(6).should == nil
+    a.at(7).should == nil
+  end
+
+  it "returns the (-n)'th element from the last, for the given negative index n" do
+    a = [1, 2, 3, 4, 5, 6]
+    a.at(-1).should == 6
+    a.at(-2).should == 5
+    a.at(-6).should == 1
+  end
+
+  it "returns nil if the given index is less than -len, where len is length of the array"  do
+    a = [1, 2, 3, 4, 5, 6]
+    a.at(-7).should == nil
+    a.at(-8).should == nil
+  end
+
+  it "does not extend the array unless the given index is out of range" do
+    a = [1, 2, 3, 4, 5, 6]
+    a.length.should == 6
+    a.at(100)
+    a.length.should == 6
+    a.at(-100)
+    a.length.should == 6
+  end
+
+  it "tries to convert the passed argument to an Integer using #to_int" do
+    a = ["a", "b", "c"]
+    a.at(0.5).should == "a"
+
+    obj = mock('to_int')
+    obj.should_receive(:to_int).and_return(2)
+    a.at(obj).should == "c"
+  end
+
+  it "raises a TypeError when the passed argument can't be coerced to Integer" do
+    -> { [].at("cat") }.should raise_error(TypeError)
+  end
+
+  it "raises an ArgumentError when 2 or more arguments are passed" do
+    -> { [:a, :b].at(0,1) }.should raise_error(ArgumentError)
+  end
+end