Ability to specify multiple contexts when defining a validation.

Example:

validates_presence_of :name, on: [:update, :custom_validation_context]

activemodel/CHANGELOG.md

@@ -1,3 +1,23 @@
+*   Ability to specify multiple contexts when defining a validation.
+
+    Example:
+
+        class Person
+          include ActiveModel::Validations
+
+          attr_reader :name
+          validates_presence_of :name, on: [:verify, :approve]
+        end
+
+        person = Person.new
+        person.valid?                           # => true
+        person.valid?(:verify)                  # => false
+        person.errors.full_messages_for(:name)  # => ["Name can't be blank"]
+        person.valid?(:approve)                 # => false
+        person.errors.full_messages_for(:name)  # => ["Name can't be blank"]
+
+    *Vince Puzzella*
+
 *   `attribute_changed?` now accepts parameters which check the old and new value of the attribute
 
     `model.name_changed?(from: "Pete", to: "Ringo")`

activemodel/lib/active_model/validations.rb

@@ -66,8 +66,10 @@ module ActiveModel
       #   end
       #
       # Options:
-      # * <tt>:on</tt> - Specifies the context where this validation is active
-      #   (e.g. <tt>on: :create</tt> or <tt>on: :custom_validation_context</tt>)
+      # * <tt>:on</tt> - Specifies the contexts where this validation is active.
+      #   You can pass a symbol or an array of symbols.
+      #   (e.g. <tt>on: :create</tt> or <tt>on: :custom_validation_context</tt> or
+      #   <tt>on: [:create, :custom_validation_context]</tt>)
       # * <tt>:allow_nil</tt> - Skip validation if attribute is +nil+.
       # * <tt>:allow_blank</tt> - Skip validation if attribute is blank.
       # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
@@ -124,8 +126,10 @@ module ActiveModel
       #   end
       #
       # Options:
-      # * <tt>:on</tt> - Specifies the context where this validation is active
-      #   (e.g. <tt>on: :create</tt> or <tt>on: :custom_validation_context</tt>)
+      # * <tt>:on</tt> - Specifies the contexts where this validation is active.
+      #   You can pass a symbol or an array of symbols.
+      #   (e.g. <tt>on: :create</tt> or <tt>on: :custom_validation_context</tt> or
+      #   <tt>on: [:create, :custom_validation_context]</tt>)
       # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
       #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
       #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
@@ -141,7 +145,7 @@ module ActiveModel
           options = options.dup
           options[:if] = Array(options[:if])
           options[:if].unshift lambda { |o|
-            o.validation_context == options[:on]
+            Array(options[:on]).include?(o.validation_context)
           }
         end
         args << options

activemodel/test/cases/validations/validations_context_test.rb

@@ -36,4 +36,20 @@ class ValidationsContextTest < ActiveModel::TestCase
     assert topic.invalid?(:create), "Validation does run on create if 'on' is set to create"
     assert topic.errors[:base].include?(ERROR_MESSAGE)
   end
+
+  test "with a class that adds errors on multiple contexts and validating a new model with no arguments" do
+    Topic.validates_with(ValidatorThatAddsErrors, on: [:context1, :context2])
+    topic = Topic.new
+    assert topic.valid?, "Validation doesn't run when 'on' is set to context1 and context2"
+  end
+
+  test "with a class that adds errors on multiple contexts and validating a new model" do
+    Topic.validates_with(ValidatorThatAddsErrors, on: [:context1, :context2])
+    topic = Topic.new
+    assert topic.invalid?(:context1), "Validation does run on context1 when 'on' is set to context1 and context2"
+    assert topic.errors[:base].include?(ERROR_MESSAGE)
+    topic = Topic.new
+    assert topic.invalid?(:context2), "Validation does run on context2 when 'on' is set to context1 and context2"
+    assert topic.errors[:base].include?(ERROR_MESSAGE)
+  end
 end