1 files changed, 130 insertions, 0 deletions
diff --git a/spec/ruby/core/struct/deconstruct_keys_spec.rb b/spec/ruby/core/struct/deconstruct_keys_spec.rb
new file mode 100644
index 0000000000..e16b50f930
--- /dev/null
+++ b/spec/ruby/core/struct/deconstruct_keys_spec.rb
@@ -0,0 +1,130 @@
+require_relative '../../spec_helper'
+
+describe "Struct#deconstruct_keys" do
+  it "returns a hash of attributes" do
+    struct = Struct.new(:x, :y)
+    s = struct.new(1, 2)
+
+    s.deconstruct_keys([:x, :y]).should == {x: 1, y: 2}
+  end
+
+  it "requires one argument" do
+    struct = Struct.new(:x)
+    obj = struct.new(1)
+
+    -> {
+      obj.deconstruct_keys
+    }.should raise_error(ArgumentError, /wrong number of arguments \(given 0, expected 1\)/)
+  end
+
+  it "returns only specified keys" do
+    struct = Struct.new(:x, :y, :z)
+    s = struct.new(1, 2, 3)
+
+    s.deconstruct_keys([:x, :y]).should == {x: 1, y: 2}
+    s.deconstruct_keys([:x]    ).should == {x: 1}
+    s.deconstruct_keys([]      ).should == {}
+  end
+
+  it "accepts string attribute names" do
+    struct = Struct.new(:x, :y)
+    s = struct.new(1, 2)
+
+    s.deconstruct_keys(['x', 'y']).should == {'x' => 1, 'y' => 2}
+  end
+
+  it "accepts argument position number as well but returns them as keys" do
+    struct = Struct.new(:x, :y, :z)
+    s = struct.new(10, 20, 30)
+
+    s.deconstruct_keys([0, 1, 2]).should == {0 => 10, 1 => 20, 2 => 30}
+    s.deconstruct_keys([0, 1]   ).should == {0 => 10, 1 => 20}
+    s.deconstruct_keys([0]      ).should == {0 => 10}
+    s.deconstruct_keys([-1]     ).should == {-1 => 30}
+  end
+
+  it "ignores incorrect position numbers" do
+    struct = Struct.new(:x, :y, :z)
+    s = struct.new(10, 20, 30)
+
+    s.deconstruct_keys([0, 3]).should == {0 => 10}
+  end
+
+  it "support mixing attribute names and argument position numbers" do
+    struct = Struct.new(:x, :y)
+    s = struct.new(1, 2)
+
+    s.deconstruct_keys([0, :x]).should == {0 => 1, :x => 1}
+  end
+
+  it "returns an empty hash when there are more keys than attributes" do
+    struct = Struct.new(:x, :y)
+    s = struct.new(1, 2)
+
+    s.deconstruct_keys([:x, :y, :a]).should == {}
+  end
+
+  it "returns at first not existing attribute name" do
+    struct = Struct.new(:x, :y)
+    s = struct.new(1, 2)
+
+    s.deconstruct_keys([:a, :x]).should == {}
+    s.deconstruct_keys([:x, :a]).should == {x: 1}
+  end
+
+  it "returns at first not existing argument position number" do
+    struct = Struct.new(:x, :y)
+    s = struct.new(1, 2)
+
+    s.deconstruct_keys([3, 0]).should == {}
+    s.deconstruct_keys([0, 3]).should == {0 => 1}
+  end
+
+  it "accepts nil argument and return all the attributes" do
+    struct = Struct.new(:x, :y)
+    obj = struct.new(1, 2)
+
+    obj.deconstruct_keys(nil).should == {x: 1, y: 2}
+  end
+
+  it "tries to convert a key with #to_int if index is not a String nor a Symbol, but responds to #to_int" do
+    struct = Struct.new(:x, :y)
+    s = struct.new(1, 2)
+
+    key = mock("to_int")
+    key.should_receive(:to_int).and_return(1)
+
+    s.deconstruct_keys([key]).should == { key => 2 }
+  end
+
+  it "raises a TypeError if the conversion with #to_int does not return an Integer" do
+    struct = Struct.new(:x, :y)
+    s = struct.new(1, 2)
+
+    key = mock("to_int")
+    key.should_receive(:to_int).and_return("not an Integer")
+
+    -> {
+      s.deconstruct_keys([key])
+    }.should raise_error(TypeError, /can't convert MockObject to Integer/)
+  end
+
+  it "raises TypeError if index is not a String, a Symbol and not convertible to Integer" do
+    struct = Struct.new(:x, :y)
+    s = struct.new(1, 2)
+
+    -> {
+      s.deconstruct_keys([0, []])
+    }.should raise_error(TypeError, "no implicit conversion of Array into Integer")
+  end
+
+  it "raise TypeError if passed anything except nil or array" do
+    struct = Struct.new(:x, :y)
+    s = struct.new(1, 2)
+
+    -> { s.deconstruct_keys('x') }.should raise_error(TypeError, /expected Array or nil/)
+    -> { s.deconstruct_keys(1)   }.should raise_error(TypeError, /expected Array or nil/)
+    -> { s.deconstruct_keys(:x)  }.should raise_error(TypeError, /expected Array or nil/)
+    -> { s.deconstruct_keys({})  }.should raise_error(TypeError, /expected Array or nil/)
+  end
+end