1 files changed, 50 insertions, 0 deletions
diff --git a/spec/ruby/core/hash/assoc_spec.rb b/spec/ruby/core/hash/assoc_spec.rb
new file mode 100644
index 0000000000..0b10720b6f
--- /dev/null
+++ b/spec/ruby/core/hash/assoc_spec.rb
@@ -0,0 +1,50 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+describe "Hash#assoc" do
+  before :each do
+    @h = {apple: :green, orange: :orange, grape: :green, banana: :yellow}
+  end
+
+  it "returns an Array if the argument is == to a key of the Hash" do
+    @h.assoc(:apple).should be_an_instance_of(Array)
+  end
+
+  it "returns a 2-element Array if the argument is == to a key of the Hash" do
+    @h.assoc(:grape).size.should == 2
+  end
+
+  it "sets the first element of the Array to the located key" do
+    @h.assoc(:banana).first.should == :banana
+  end
+
+  it "sets the last element of the Array to the value of the located key" do
+    @h.assoc(:banana).last.should == :yellow
+  end
+
+  it "only returns the first matching key-value pair for identity hashes" do
+    # Avoid literal String keys in Hash#[]= due to https://bugs.ruby-lang.org/issues/12855
+    h = {}.compare_by_identity
+    k1 = 'pear'
+    h[k1] = :red
+    k2 = 'pear'
+    h[k2] = :green
+    h.size.should == 2
+    h.keys.grep(/pear/).size.should == 2
+    h.assoc('pear').should == ['pear', :red]
+  end
+
+  it "uses #== to compare the argument to the keys" do
+    @h[1.0] = :value
+    1.should == 1.0
+    @h.assoc(1).should == [1.0, :value]
+  end
+
+  it "returns nil if the argument is not a key of the Hash" do
+    @h.assoc(:green).should be_nil
+  end
+
+  it "returns nil if the argument is not a key of the Hash even when there is a default" do
+    Hash.new(42).merge!( foo: :bar ).assoc(42).should be_nil
+    Hash.new{|h, k| h[k] = 42}.merge!( foo: :bar ).assoc(42).should be_nil
+  end
+end