1 files changed, 93 insertions, 0 deletions
diff --git a/spec/rubyspec/core/array/first_spec.rb b/spec/rubyspec/core/array/first_spec.rb
new file mode 100644
index 0000000000..60a0a76594
--- /dev/null
+++ b/spec/rubyspec/core/array/first_spec.rb
@@ -0,0 +1,93 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "Array#first" do
+  it "returns the first element" do
+    %w{a b c}.first.should == 'a'
+    [nil].first.should == nil
+  end
+
+  it "returns nil if self is empty" do
+    [].first.should == nil
+  end
+
+  it "returns the first count elements if given a count" do
+    [true, false, true, nil, false].first(2).should == [true, false]
+  end
+
+  it "returns an empty array when passed count on an empty array" do
+    [].first(0).should == []
+    [].first(1).should == []
+    [].first(2).should == []
+  end
+
+  it "returns an empty array when passed count == 0" do
+    [1, 2, 3, 4, 5].first(0).should == []
+  end
+
+  it "returns an array containing the first element when passed count == 1" do
+    [1, 2, 3, 4, 5].first(1).should == [1]
+  end
+
+  it "raises an ArgumentError when count is negative" do
+    lambda { [1, 2].first(-1) }.should raise_error(ArgumentError)
+  end
+
+  it "raises a RangeError when count is a Bignum" do
+    lambda { [].first(bignum_value) }.should raise_error(RangeError)
+  end
+
+  it "returns the entire array when count > length" do
+    [1, 2, 3, 4, 5, 9].first(10).should == [1, 2, 3, 4, 5, 9]
+  end
+
+  it "returns an array which is independent to the original when passed count" do
+    ary = [1, 2, 3, 4, 5]
+    ary.first(0).replace([1,2])
+    ary.should == [1, 2, 3, 4, 5]
+    ary.first(1).replace([1,2])
+    ary.should == [1, 2, 3, 4, 5]
+    ary.first(6).replace([1,2])
+    ary.should == [1, 2, 3, 4, 5]
+  end
+
+  it "properly handles recursive arrays" do
+    empty = ArraySpecs.empty_recursive_array
+    empty.first.should equal(empty)
+
+    ary = ArraySpecs.head_recursive_array
+    ary.first.should equal(ary)
+  end
+
+  it "tries to convert the passed argument to an Integer using #to_int" do
+    obj = mock('to_int')
+    obj.should_receive(:to_int).and_return(2)
+    [1, 2, 3, 4, 5].first(obj).should == [1, 2]
+  end
+
+  it "raises a TypeError if the passed argument is not numeric" do
+    lambda { [1,2].first(nil) }.should raise_error(TypeError)
+    lambda { [1,2].first("a") }.should raise_error(TypeError)
+
+    obj = mock("nonnumeric")
+    lambda { [1,2].first(obj) }.should raise_error(TypeError)
+  end
+
+  it "does not return subclass instance when passed count on Array subclasses" do
+    ArraySpecs::MyArray[].first(0).should be_an_instance_of(Array)
+    ArraySpecs::MyArray[].first(2).should be_an_instance_of(Array)
+    ArraySpecs::MyArray[1, 2, 3].first(0).should be_an_instance_of(Array)
+    ArraySpecs::MyArray[1, 2, 3].first(1).should be_an_instance_of(Array)
+    ArraySpecs::MyArray[1, 2, 3].first(2).should be_an_instance_of(Array)
+  end
+
+  it "is not destructive" do
+    a = [1, 2, 3]
+    a.first
+    a.should == [1, 2, 3]
+    a.first(2)
+    a.should == [1, 2, 3]
+    a.first(3)
+    a.should == [1, 2, 3]
+  end
+end