support multiple guards per transition

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 ## 3.1.0 (not yet released)
 
+ * support multiple guards per transition
  * allow configuring behavior of nested transactions (see [issue #107](https://github.com/aasm/aasm/issues/107))
  * validating the current state (see [issue #95](https://github.com/aasm/aasm/issues/95), thanks to [@ivantsepp](https://github.com/ivantsepp))
 

README.md

@@ -193,6 +193,13 @@ job.may_sleep?  # => false
 job.sleep       # => raises AASM::InvalidTransition
 ```
 
+You can even provide a number of guards, which all have to succeed to proceed
+
+```ruby
+    event :sleep do
+      transitions :from => :running, :to => :sleeping, :guards => [:cleaning_needed?, :walked_the_dog?]
+    end
+```
 
 ### ActiveRecord
 

lib/aasm/transition.rb

@@ -4,20 +4,24 @@ class Transition
     alias_method :options, :opts
 
     def initialize(opts)
-      @from, @to, @guard, @on_transition = opts[:from], opts[:to], opts[:guard], opts[:on_transition]
+      @from = opts[:from]
+      @to = opts[:to]
+      @guards = Array(opts[:guard] || opts[:guards])
+      @on_transition = opts[:on_transition]
       @opts = opts
     end
 
     # TODO: should be named allowed? or similar
     def perform(obj, *args)
-      case @guard
+      @guards.each do |guard|
+        case guard
         when Symbol, String
-          obj.send(@guard, *args)
+          return false unless obj.send(guard, *args)
         when Proc
-          @guard.call(obj, *args)
-        else
-          true
+          return false unless guard.call(obj, *args)
+        end
       end
+      true
     end
 
     def execute(obj, *args)

spec/models/guardian.rb

@@ -0,0 +1,37 @@
+class Guardian
+  include AASM
+
+  aasm do
+    state :alpha, :initial => true
+    state :beta
+
+    event :use_one_guard_that_succeeds do
+      transitions :from => :alpha, :to => :beta, :guard => :succeed
+    end
+    event :use_one_guard_that_fails do
+      transitions :from => :alpha, :to => :beta, :guard => :fail
+    end
+    event :use_guards_that_succeed do
+      transitions :from => :alpha, :to => :beta, :guards => [:succeed, :another_succeed]
+    end
+    event :use_guards_where_the_first_fails do
+      transitions :from => :alpha, :to => :beta, :guards => [:succeed, :fail]
+    end
+    event :use_guards_where_the_second_fails do
+      transitions :from => :alpha, :to => :beta, :guards => [:fail, :succeed]
+    end
+  end
+
+  def fail
+    false
+  end
+
+  def succeed
+    true
+  end
+
+  def another_succeed
+    true
+  end
+
+end

spec/unit/guard_spec.rb

@@ -0,0 +1,30 @@
+require 'spec_helper'
+
+describe "per-transition guards" do
+  let(:guardian) { Guardian.new }
+
+  it "allows the transition if the guard succeeds" do
+    expect { guardian.use_one_guard_that_succeeds! }.to_not raise_error
+    expect(guardian).to be_beta
+  end
+
+  it "stops the transition if the guard fails" do
+    expect { guardian.use_one_guard_that_fails! }.to raise_error(AASM::InvalidTransition)
+    expect(guardian).to be_alpha
+  end
+
+  it "allows the transition if all guards succeeds" do
+    expect { guardian.use_guards_that_succeed! }.to_not raise_error
+    expect(guardian).to be_beta
+  end
+
+  it "stops the transition if the first guard fails" do
+    expect { guardian.use_guards_where_the_first_fails! }.to raise_error(AASM::InvalidTransition)
+    expect(guardian).to be_alpha
+  end
+
+  it "stops the transition if the second guard fails" do
+    expect { guardian.use_guards_where_the_second_fails! }.to raise_error(AASM::InvalidTransition)
+    expect(guardian).to be_alpha
+  end
+end