diff --git a/lib/active_meta/attribute.rb b/lib/active_meta/attribute.rb
index 8f00143..a63712d 100644
--- a/lib/active_meta/attribute.rb
+++ b/lib/active_meta/attribute.rb
@@ -31,9 +31,7 @@ def overload(&block)
     end
 
     def register_rule(rule)
-      unless rule.is_a? ActiveMeta::Rule
-        raise ArgumentError, "no rule given for attribute #{@attribute}"
-      end
+      raise ArgumentError, "no rule given for attribute #{@attribute}" unless rule.is_a? ActiveMeta::Rule
       # rule.attribute = self.attribute
       rule.contexts = @context_chain
       rule.parent = self
@@ -41,7 +39,7 @@ def register_rule(rule)
     end
 
     def [](arg)
-      rules.select(&:validates_context?).find{|rule| rule.rule_name.to_s == arg.to_s }
+      rules.select(&:validates_context?).find { |rule| rule.rule_name.to_s == arg.to_s }
     end
 
   end
diff --git a/lib/active_meta/context.rb b/lib/active_meta/context.rb
index ed94365..c0984ba 100644
--- a/lib/active_meta/context.rb
+++ b/lib/active_meta/context.rb
@@ -3,7 +3,7 @@ module Context
     class << self
       def new(&block)
         raise ArgumentError, 'no block given for context' unless block_given?
-        mod = Module.new do
+        Module.new do
           @eval_block = block
           class << self
             def valid_for_rule?(rule)
diff --git a/lib/active_meta/core.rb b/lib/active_meta/core.rb
index 72c327e..e69ac4a 100644
--- a/lib/active_meta/core.rb
+++ b/lib/active_meta/core.rb
@@ -46,7 +46,7 @@ def rules
 
     def [](*args)
       args = args.map(&:to_s)
-      rules.select{|rule| args.include? rule.rule_name.to_s }
+      rules.select { |rule| args.include? rule.rule_name.to_s }
     end
   end
 end
diff --git a/lib/active_meta/rule.rb b/lib/active_meta/rule.rb
index 0a102c0..458bec3 100644
--- a/lib/active_meta/rule.rb
+++ b/lib/active_meta/rule.rb
@@ -6,11 +6,11 @@ class Rule
     alias_method :args, :arguments
 
     def initialize(attribute, rule_name, *arguments)
-      unless /^[a-z_]+$/ =~ attribute
-        raise ArgumentError, "invalide attribute #{attribute}"
+      unless /\A[a-z_]+\z/ =~ attribute
+        raise ArgumentError, "invalid attribute #{attribute}"
       end
-      unless /^[a-z_]+$/ =~ rule_name
-        raise ArgumentError, "invalide rule_name for attribute #{attribute}"
+      unless /\A[a-z_]+\z/ =~ rule_name
+        raise ArgumentError, "invalid rule_name for attribute #{attribute}"
       end
       @attribute = attribute
       @rule_name = rule_name
@@ -27,9 +27,9 @@ def opts
 
     def validates_context?
       @validates_context ||= begin
-        if contexts && contexts.length > 0
-          context_classes = contexts.map{|context| ActiveMeta::Contexts.const_get(context) }
-          context_classes.all?{|ctx| ctx.valid_for_rule?(self) }
+        if contexts && !contexts.empty?
+          context_classes = contexts.map { |context| ActiveMeta::Contexts.const_get(context) }
+          context_classes.all? { |ctx| ctx.valid_for_rule?(self) }
         else
           true
         end
diff --git a/spec/lib/active_meta/rule_spec.rb b/spec/lib/active_meta/rule_spec.rb
index d0b4e56..58d8c67 100644
--- a/spec/lib/active_meta/rule_spec.rb
+++ b/spec/lib/active_meta/rule_spec.rb
@@ -12,11 +12,24 @@
   context 'instance methods' do
     context '#initialize' do
       it 'should raise an ArgumentError if passed attribute is invalid' do
-        ->{ subject.new('Foo', 't') }.should raise_error ArgumentError
+        -> { subject.new('Foo', 't') }.should raise_error ArgumentError
       end
 
-      it 'should raise an ArgumentError if passed attribute is invalid' do
-        ->{ subject.new('t', 'Foo') }.should raise_error ArgumentError
+      it 'should raise an ArgumentError if passed rule_name is invalid' do
+        -> { subject.new('t', 'Foo') }.should raise_error ArgumentError
+      end
+
+      # http://ruby-doc.org/core-2.2.1/Regexp.html#class-Regexp-label-Anchors
+      it 'should raise an ArgumentError if a multiline string is passed as attribute' do
+        arg = "i_am_valid but_not_now".gsub(' ', "\n")
+
+        -> { subject.new(arg, 't') }.should raise_error ArgumentError
+      end
+
+      it 'should raise an ArgumentError if a multiline string is passed as rule_name' do
+        arg = "i_am_valid but_not_now".gsub(' ', "\n")
+
+        -> { subject.new('t', arg) }.should raise_error ArgumentError
       end
 
       it 'should store `attribute` as @attribute' do