better consistency around email case sensitivity

spec/components/email_spec.rb

@@ -3,20 +3,39 @@ require 'email'
 
 describe Email do
 
+  describe "is_valid?" do
+
+    it 'treats a good email as valid' do
+      Email.is_valid?('sam@sam.com').should be_true
+    end
+
+    it 'treats a bad email as invalid' do
+      Email.is_valid?('sam@sam').should be_false
+    end
+
+    it 'allows museum tld' do
+      Email.is_valid?('sam@nic.museum').should be_true
+    end
+
+    it 'does not think a word is an email' do
+      Email.is_valid?('sam').should be_false
+    end
 
-  it 'should treat a good email as valid' do
-    Email.is_valid?('sam@sam.com').should be_true
   end
 
-  it 'should treat a bad email as invalid' do
-    Email.is_valid?('sam@sam').should be_false
+  describe "downcase" do
+
+    it 'downcases only the host part' do
+      Email.downcase('SAM@GMAIL.COM').should == 'SAM@gmail.com'
+      Email.downcase('sam@GMAIL.COM').should_not == 'SAM@gmail.com'
+    end
+
+    it 'leaves invalid emails untouched' do
+      Email.downcase('SAM@GMAILCOM').should == 'SAM@GMAILCOM'
+      Email.downcase('samGMAIL.COM').should == 'samGMAIL.COM'
+      Email.downcase('sam@GM@AIL.COM').should == 'sam@GM@AIL.COM'
+    end
+
   end
 
-  it 'should allow museum tld' do
-    Email.is_valid?('sam@nic.museum').should be_true
-  end
-
-  it 'should not think a word is an email' do
-    Email.is_valid?('sam').should be_false
-  end
 end