Added src directory

src/about_hashes.rb

@@ -0,0 +1,66 @@
+require 'edgecase'
+
+class AboutHashes < EdgeCase::Koan
+  def test_creating_hashes
+    empty_hash = Hash.new
+    assert_equal Hash, empty_hash.class
+    assert_equal({}, empty_hash)
+    assert_equal __(0), empty_hash.size
+  end
+
+  def test_hash_literals
+    hash = { :one => "uno", :two => "dos" }
+    assert_equal __(2), hash.size
+  end
+
+  def test_accessing_hashes
+    hash = { :one => "uno", :two => "dos" }
+    assert_equal __("uno"), hash[:one]
+    assert_equal __("dos"), hash[:two]
+    assert_equal __(nil), hash[:doesnt_exist]
+  end
+
+  def test_changing_hashes
+    hash = { :one => "uno", :two => "dos" }
+    hash[:one] = "eins"
+
+    expected = { :one => __("eins"), :two => "dos" }
+    assert_equal expected, hash
+
+    # Bonus Question: Why was "expected" broken out into a variable
+    # rather than used as a literal?
+  end
+
+  def test_hash_is_unordered
+    hash1 = { :one => "uno", :two => "dos" }
+    hash2 = { :two => "dos", :one => "uno" }
+
+    assert_equal hash1, hash2
+  end
+
+  def test_hash_keys
+    hash = { :one => "uno", :two => "dos" }
+    assert_equal __(2), hash.keys.size
+    assert_equal __(true), hash.keys.include?(:one)
+    assert_equal __(true), hash.keys.include?(:two)
+    assert_equal Array, hash.keys.class
+  end
+
+  def test_hash_values
+    hash = { :one => "uno", :two => "dos" }
+    assert_equal __(2), hash.keys.size
+    assert_equal __(true), hash.values.include?("uno")
+    assert_equal __(true), hash.values.include?("dos")
+    assert_equal Array, hash.values.class
+  end
+
+  def test_combining_hashes
+    hash = { "jim" => 53, "amy" => 20, "dan" => 23 }
+    new_hash = hash.merge({ "jim" => 54, "jenny" => 26 })
+
+    assert_not_equal hash, new_hash
+    
+    expected = { "jim" => __(54), "amy" => 20, "dan" => 23, "jenny" => __(26) }
+    assert_equal expected, new_hash
+  end
+end