fix: email is required (#457)

lib/sendgrid/helpers/mail/email.rb

@@ -4,7 +4,9 @@ module SendGrid
   class Email
     attr_accessor :email, :name
 
-    def initialize(email: nil, name: nil)
+    # @param [String] email required e-mail address
+    # @param [String] name optionally personification
+    def initialize(email:, name: nil)
       if name
         @email = email
         @name = name
@@ -15,6 +17,8 @@ def initialize(email: nil, name: nil)
 
     def split_email(email)
       split = /(?:(?<address>.+)\s)?<?(?<email>.+@[^>]+)>?/.match(email)
+      raise ArgumentError, "email (#{email}) is invalid" unless split
+
       [split[:email], split[:address]]
     end
 

test/sendgrid/helpers/mail/test_email.rb

@@ -29,4 +29,13 @@ def test_split_email_name_and_email
     }
     assert_equal @email.to_json, expected_json
   end
+
+  def test_mandatory_email_missing
+    assert_raises(ArgumentError) { Email.new(email: nil) }
+    assert_raises(ArgumentError) { Email.new(email: "") }
+  end
+
+  def test_invalid_email
+    assert_raises(ArgumentError) { Email.new(email: "some-invalid-string") }
+  end
 end