diff --git a/aasm.gemspec b/aasm.gemspec
index 43c61b3..3826dcf 100644
--- a/aasm.gemspec
+++ b/aasm.gemspec
@@ -19,7 +19,7 @@ Gem::Specification.new do |s|
   # s.add_development_dependency 'mongoid' if Gem::Version.create(RUBY_VERSION.dup) >= Gem::Version.create('1.9.3')
   s.add_development_dependency 'rake'
   s.add_development_dependency 'sdoc'
-  s.add_development_dependency 'rspec', '~> 2.14'
+  s.add_development_dependency 'rspec', '>= 2.14'
   s.add_development_dependency 'rr'
   # s.add_development_dependency 'sqlite3'
   s.add_development_dependency 'minitest'
diff --git a/spec/unit/api_spec.rb b/spec/unit/api_spec.rb
index 6ab736b..5da2a9e 100644
--- a/spec/unit/api_spec.rb
+++ b/spec/unit/api_spec.rb
@@ -3,19 +3,19 @@ require 'models/active_record/api.rb'
 
 describe "reading the current state" do
   it "uses the AASM default" do
-    DefaultState.new.aasm.current_state.should eql :alpha
+    expect(DefaultState.new.aasm.current_state).to eql :alpha
   end
 
   it "uses the provided method" do
-    ProvidedState.new.aasm.current_state.should eql :beta
+    expect(ProvidedState.new.aasm.current_state).to eql :beta
   end
 
   it "uses the persistence storage" do
-    PersistedState.new.aasm.current_state.should eql :alpha
+    expect(PersistedState.new.aasm.current_state).to eql :alpha
   end
 
   it "uses the provided method even if persisted" do
-    ProvidedAndPersistedState.new.aasm.current_state.should eql :gamma
+    expect(ProvidedAndPersistedState.new.aasm.current_state).to eql :gamma
   end
 end
 
@@ -23,25 +23,25 @@ describe "writing and persisting the current state" do
   it "uses the AASM default" do
     o = DefaultState.new
     o.release!
-    o.persisted_store.should be_nil
+    expect(o.persisted_store).to be_nil
   end
 
   it "uses the provided method" do
     o = ProvidedState.new
     o.release!
-    o.persisted_store.should eql :beta
+    expect(o.persisted_store).to eql :beta
   end
 
   it "uses the persistence storage" do
     o = PersistedState.new
     o.release!
-    o.persisted_store.should be_nil
+    expect(o.persisted_store).to be_nil
   end
 
   it "uses the provided method even if persisted" do
     o = ProvidedAndPersistedState.new
     o.release!
-    o.persisted_store.should eql :beta
+    expect(o.persisted_store).to eql :beta
   end
 end
 
@@ -49,24 +49,24 @@ describe "writing the current state without persisting it" do
   it "uses the AASM default" do
     o = DefaultState.new
     o.release
-    o.transient_store.should be_nil
+    expect(o.transient_store).to be_nil
   end
 
   it "uses the provided method" do
     o = ProvidedState.new
     o.release
-    o.transient_store.should eql :beta
+    expect(o.transient_store).to eql :beta
   end
 
   it "uses the persistence storage" do
     o = PersistedState.new
     o.release
-    o.transient_store.should be_nil
+    expect(o.transient_store).to be_nil
   end
 
   it "uses the provided method even if persisted" do
     o = ProvidedAndPersistedState.new
     o.release
-    o.transient_store.should eql :beta
+    expect(o.transient_store).to eql :beta
   end
 end
diff --git a/spec/unit/callbacks_spec.rb b/spec/unit/callbacks_spec.rb
index 4bad201..f8a8540 100644
--- a/spec/unit/callbacks_spec.rb
+++ b/spec/unit/callbacks_spec.rb
@@ -4,15 +4,15 @@ describe 'callbacks for the new DSL' do
   let(:callback) {CallbackNewDsl.new}
 
   it "be called in order" do
-    callback.should_receive(:exit_open).once.ordered
-    callback.should_receive(:before).once.ordered
-    callback.should_receive(:before_exit_open).once.ordered                   # these should be before the state changes
-    callback.should_receive(:before_enter_closed).once.ordered
-    callback.should_receive(:enter_closed).once.ordered
-    callback.should_receive(:aasm_write_state).once.ordered.and_return(true)  # this is when the state changes
-    callback.should_receive(:after_exit_open).once.ordered                    # these should be after the state changes
-    callback.should_receive(:after_enter_closed).once.ordered
-    callback.should_receive(:after).once.ordered
+    expect(callback).to receive(:exit_open).once.ordered
+    expect(callback).to receive(:before).once.ordered
+    expect(callback).to receive(:before_exit_open).once.ordered                   # these should be before the state changes
+    expect(callback).to receive(:before_enter_closed).once.ordered
+    expect(callback).to receive(:enter_closed).once.ordered
+    expect(callback).to receive(:aasm_write_state).once.ordered.and_return(true)  # this is when the state changes
+    expect(callback).to receive(:after_exit_open).once.ordered                    # these should be after the state changes
+    expect(callback).to receive(:after_enter_closed).once.ordered
+    expect(callback).to receive(:after).once.ordered
 
     callback.close!
   end
@@ -35,20 +35,20 @@ describe 'event callbacks' do
     it "should run error_callback if an exception is raised and error_callback defined" do
       def @foo.error_callback(e); end
 
-      @foo.stub(:enter).and_raise(e=StandardError.new)
-      @foo.should_receive(:error_callback).with(e)
+      allow(@foo).to receive(:enter).and_raise(e=StandardError.new)
+      expect(@foo).to receive(:error_callback).with(e)
 
       @foo.safe_close!
     end
 
     it "should raise NoMethodError if exceptionis raised and error_callback is declared but not defined" do
-      @foo.stub(:enter).and_raise(StandardError)
-      lambda{@foo.safe_close!}.should raise_error(NoMethodError)
+      allow(@foo).to receive(:enter).and_raise(StandardError)
+      expect{@foo.safe_close!}.to raise_error(NoMethodError)
     end
 
     it "should propagate an error if no error callback is declared" do
-        @foo.stub(:enter).and_raise("Cannot enter safe")
-        lambda{@foo.close!}.should raise_error(StandardError, "Cannot enter safe")
+        allow(@foo).to receive(:enter).and_raise("Cannot enter safe")
+        expect{@foo.close!}.to raise_error(StandardError, "Cannot enter safe")
     end
   end
 
@@ -59,18 +59,18 @@ describe 'event callbacks' do
     end
 
     it 'should call it for successful bang fire' do
-      @foo.should_receive(:aasm_event_fired).with(:close, :open, :closed)
+      expect(@foo).to receive(:aasm_event_fired).with(:close, :open, :closed)
       @foo.close!
     end
 
     it 'should call it for successful non-bang fire' do
-      @foo.should_receive(:aasm_event_fired)
+      expect(@foo).to receive(:aasm_event_fired)
       @foo.close
     end
 
     it 'should not call it for failing bang fire' do
-      @foo.aasm.stub(:set_current_state_with_persistence).and_return(false)
-      @foo.should_not_receive(:aasm_event_fired)
+      allow(@foo.aasm).to receive(:set_current_state_with_persistence).and_return(false)
+      expect(@foo).not_to receive(:aasm_event_fired)
       @foo.close!
     end
   end
@@ -82,18 +82,18 @@ describe 'event callbacks' do
     end
 
     it 'should call it when transition failed for bang fire' do
-      @foo.should_receive(:aasm_event_failed).with(:null, :open)
-      lambda {@foo.null!}.should raise_error(AASM::InvalidTransition)
+      expect(@foo).to receive(:aasm_event_failed).with(:null, :open)
+      expect {@foo.null!}.to raise_error(AASM::InvalidTransition)
     end
 
     it 'should call it when transition failed for non-bang fire' do
-      @foo.should_receive(:aasm_event_failed).with(:null, :open)
-      lambda {@foo.null}.should raise_error(AASM::InvalidTransition)
+      expect(@foo).to receive(:aasm_event_failed).with(:null, :open)
+      expect {@foo.null}.to raise_error(AASM::InvalidTransition)
     end
 
     it 'should not call it if persist fails for bang fire' do
-      @foo.aasm.stub(:set_current_state_with_persistence).and_return(false)
-      @foo.should_receive(:aasm_event_failed)
+      allow(@foo.aasm).to receive(:set_current_state_with_persistence).and_return(false)
+      expect(@foo).to receive(:aasm_event_failed)
       @foo.close!
     end
   end
diff --git a/spec/unit/complex_example_spec.rb b/spec/unit/complex_example_spec.rb
index 89e1884..7c64801 100644
--- a/spec/unit/complex_example_spec.rb
+++ b/spec/unit/complex_example_spec.rb
@@ -4,12 +4,12 @@ describe 'on initialization' do
   let(:auth) {AuthMachine.new}
 
   it 'should be in the pending state' do
-    auth.aasm.current_state.should == :pending
+    expect(auth.aasm.current_state).to eq(:pending)
   end
 
   it 'should have an activation code' do
-    auth.has_activation_code?.should be_true
-    auth.activation_code.should_not be_nil
+    expect(auth.has_activation_code?).to be_true
+    expect(auth.activation_code).not_to be_nil
   end
 end
 
@@ -19,26 +19,26 @@ describe 'when being unsuspended' do
   it 'should be able to be unsuspended' do
     auth.activate!
     auth.suspend!
-    auth.may_unsuspend?.should be_true
+    expect(auth.may_unsuspend?).to be_true
   end
 
   it 'should not be able to be unsuspended into active' do
     auth.suspend!
-    auth.may_unsuspend?(:active).should_not be_true
+    expect(auth.may_unsuspend?(:active)).not_to be_true
   end
 
   it 'should be able to be unsuspended into active if polite' do
     auth.suspend!
-    auth.may_wait?(:waiting, :please).should be_true
+    expect(auth.may_wait?(:waiting, :please)).to be_true
     auth.wait!(nil, :please)
   end
 
   it 'should not be able to be unsuspended into active if not polite' do
     auth.suspend!
-    auth.may_wait?(:waiting).should_not be_true
-    auth.may_wait?(:waiting, :rude).should_not be_true
-    lambda {auth.wait!(nil, :rude)}.should raise_error(AASM::InvalidTransition)
-    lambda {auth.wait!}.should raise_error(AASM::InvalidTransition)
+    expect(auth.may_wait?(:waiting)).not_to be_true
+    expect(auth.may_wait?(:waiting, :rude)).not_to be_true
+    expect {auth.wait!(nil, :rude)}.to raise_error(AASM::InvalidTransition)
+    expect {auth.wait!}.to raise_error(AASM::InvalidTransition)
   end
 
   it 'should not be able to be unpassified' do
@@ -46,8 +46,8 @@ describe 'when being unsuspended' do
     auth.suspend!
     auth.unsuspend!
 
-    auth.may_unpassify?.should_not be_true
-    lambda {auth.unpassify!}.should raise_error(AASM::InvalidTransition)
+    expect(auth.may_unpassify?).not_to be_true
+    expect {auth.unpassify!}.to raise_error(AASM::InvalidTransition)
   end
 
   it 'should be active if previously activated' do
@@ -55,14 +55,14 @@ describe 'when being unsuspended' do
     auth.suspend!
     auth.unsuspend!
 
-    auth.aasm.current_state.should == :active
+    expect(auth.aasm.current_state).to eq(:active)
   end
 
   it 'should be pending if not previously activated, but an activation code is present' do
     auth.suspend!
     auth.unsuspend!
 
-    auth.aasm.current_state.should == :pending
+    expect(auth.aasm.current_state).to eq(:pending)
   end
 
   it 'should be passive if not previously activated and there is no activation code' do
@@ -70,6 +70,6 @@ describe 'when being unsuspended' do
     auth.suspend!
     auth.unsuspend!
 
-    auth.aasm.current_state.should == :passive
+    expect(auth.aasm.current_state).to eq(:passive)
   end
 end
diff --git a/spec/unit/event_spec.rb b/spec/unit/event_spec.rb
index bc78164..7d0115c 100644
--- a/spec/unit/event_spec.rb
+++ b/spec/unit/event_spec.rb
@@ -10,27 +10,27 @@ describe 'adding an event' do
   end
 
   it 'should set the name' do
-    event.name.should == :close_order
+    expect(event.name).to eq(:close_order)
   end
 
   it 'should set the success callback' do
-    event.options[:success].should == :success_callback
+    expect(event.options[:success]).to eq(:success_callback)
   end
 
   it 'should set the after callback' do
-    event.options[:after].should == [:after_callback]
+    expect(event.options[:after]).to eq([:after_callback])
   end
 
   it 'should set the before callback' do
-    event.options[:before].should == [:before_callback]
+    expect(event.options[:before]).to eq([:before_callback])
   end
 
   it 'should create transitions' do
     transitions = event.transitions
-    transitions[0].from.should == :open
-    transitions[0].to.should == :closed
-    transitions[1].from.should == :received
-    transitions[1].to.should == :closed
+    expect(transitions[0].from).to eq(:open)
+    expect(transitions[0].to).to eq(:closed)
+    expect(transitions[1].from).to eq(:received)
+    expect(transitions[1].to).to eq(:closed)
   end
 end
 
@@ -42,19 +42,19 @@ describe 'transition inspection' do
   end
 
   it 'should support inspecting transitions from other states' do
-    event.transitions_from_state(:sleeping).map(&:to).should == [:running]
-    event.transitions_from_state?(:sleeping).should be_true
+    expect(event.transitions_from_state(:sleeping).map(&:to)).to eq([:running])
+    expect(event.transitions_from_state?(:sleeping)).to be_true
 
-    event.transitions_from_state(:cleaning).map(&:to).should == []
-    event.transitions_from_state?(:cleaning).should be_false
+    expect(event.transitions_from_state(:cleaning).map(&:to)).to eq([])
+    expect(event.transitions_from_state?(:cleaning)).to be_false
   end
 
   it 'should support inspecting transitions to other states' do
-    event.transitions_to_state(:running).map(&:from).should == [:sleeping]
-    event.transitions_to_state?(:running).should be_true
+    expect(event.transitions_to_state(:running).map(&:from)).to eq([:sleeping])
+    expect(event.transitions_to_state?(:running)).to be_true
 
-    event.transitions_to_state(:cleaning).map(&:to).should == []
-    event.transitions_to_state?(:cleaning).should be_false
+    expect(event.transitions_to_state(:cleaning).map(&:to)).to eq([])
+    expect(event.transitions_to_state?(:cleaning)).to be_false
   end
 end
 
@@ -63,7 +63,7 @@ describe 'firing an event' do
     obj = double('object', :aasm => double('aasm', :current_state => 'open'))
 
     event = AASM::Event.new(:event)
-    event.fire(obj).should be_nil
+    expect(event.fire(obj)).to be_nil
   end
 
   it 'should return the state of the first matching transition it finds' do
@@ -73,7 +73,7 @@ describe 'firing an event' do
 
     obj = double('object', :aasm => double('aasm', :current_state => :open))
 
-    event.fire(obj).should == :closed
+    expect(event.fire(obj)).to eq(:closed)
   end
 
   it 'should call the guard with the params passed in' do
@@ -82,9 +82,9 @@ describe 'firing an event' do
     end
 
     obj = double('object', :aasm => double('aasm', :current_state => :open))
-    obj.should_receive(:guard_fn).with('arg1', 'arg2').and_return(true)
+    expect(obj).to receive(:guard_fn).with('arg1', 'arg2').and_return(true)
 
-    event.fire(obj, nil, 'arg1', 'arg2').should == :closed
+    expect(event.fire(obj, nil, 'arg1', 'arg2')).to eq(:closed)
   end
 
 end
@@ -101,7 +101,7 @@ describe 'should fire callbacks' do
       }
 
       model = ThisNameBetterNotBeInUse.new
-      model.should_receive(:symbol_success_callback)
+      expect(model).to receive(:symbol_success_callback)
       model.with_symbol!
     end
 
@@ -115,7 +115,7 @@ describe 'should fire callbacks' do
       }
 
       model = ThisNameBetterNotBeInUse.new
-      model.should_receive(:string_success_callback)
+      expect(model).to receive(:string_success_callback)
       model.with_string!
     end
 
@@ -129,8 +129,8 @@ describe 'should fire callbacks' do
       }
 
       model = ThisNameBetterNotBeInUse.new
-      model.should_receive(:success_callback1)
-      model.should_receive(:success_callback2)
+      expect(model).to receive(:success_callback1)
+      expect(model).to receive(:success_callback2)
       model.with_array!
     end
 
@@ -144,9 +144,9 @@ describe 'should fire callbacks' do
       }
 
       model = ThisNameBetterNotBeInUse.new
-      model.should_receive(:success_callback1)
-      model.should_receive(:success_callback2)
-      model.should_receive(:proc_success_callback)
+      expect(model).to receive(:success_callback1)
+      expect(model).to receive(:success_callback2)
+      expect(model).to receive(:proc_success_callback)
       model.with_array_including_procs!
     end
 
@@ -160,7 +160,7 @@ describe 'should fire callbacks' do
       }
 
       model = ThisNameBetterNotBeInUse.new
-      model.should_receive(:proc_success_callback)
+      expect(model).to receive(:proc_success_callback)
       model.with_proc!
     end
   end
@@ -182,9 +182,9 @@ describe 'should fire callbacks' do
       end
 
       model = ThisNameBetterNotBeInUse.new
-      model.should_receive(:do_one_thing_after).once.ordered
-      model.should_receive(:do_another_thing_after_too).once.ordered
-      model.should_receive(:do_third_thing_at_last).once.ordered
+      expect(model).to receive(:do_one_thing_after).once.ordered
+      expect(model).to receive(:do_another_thing_after_too).once.ordered
+      expect(model).to receive(:do_third_thing_at_last).once.ordered
       model.with_afters!
     end
   end
@@ -203,7 +203,7 @@ describe 'should fire callbacks' do
       end
 
       model = ThisNameBetterNotBeInUse.new
-      model.should_receive(:do_something_before).once
+      expect(model).to receive(:do_something_before).once
       model.before_as_proc!
     end
   end
@@ -221,8 +221,8 @@ describe 'should fire callbacks' do
     end
 
     model = ThisNameBetterNotBeInUse.new
-    model.should_receive(:do_something_before).once.ordered
-    model.should_receive(:do_something_after).once.ordered
+    expect(model).to receive(:do_something_before).once.ordered
+    expect(model).to receive(:do_something_after).once.ordered
     model.in_right_order!
   end
 end
@@ -232,40 +232,40 @@ describe 'parametrised events' do
 
   it 'should transition to specified next state (sleeping to showering)' do
     pe.wakeup!(:showering)
-    pe.aasm.current_state.should == :showering
+    expect(pe.aasm.current_state).to eq(:showering)
   end
 
   it 'should transition to specified next state (sleeping to working)' do
     pe.wakeup!(:working)
-    pe.aasm.current_state.should == :working
+    expect(pe.aasm.current_state).to eq(:working)
   end
 
   it 'should transition to default (first or showering) state' do
     pe.wakeup!
-    pe.aasm.current_state.should == :showering
+    expect(pe.aasm.current_state).to eq(:showering)
   end
 
   it 'should transition to default state when on_transition invoked' do
     pe.dress!(nil, 'purple', 'dressy')
-    pe.aasm.current_state.should == :working
+    expect(pe.aasm.current_state).to eq(:working)
   end
 
   it 'should call on_transition method with args' do
     pe.wakeup!(:showering)
-    pe.should_receive(:wear_clothes).with('blue', 'jeans')
+    expect(pe).to receive(:wear_clothes).with('blue', 'jeans')
     pe.dress!(:working, 'blue', 'jeans')
   end
 
   it 'should call on_transition proc' do
     pe.wakeup!(:showering)
-    pe.should_receive(:wear_clothes).with('purple', 'slacks')
+    expect(pe).to receive(:wear_clothes).with('purple', 'slacks')
     pe.dress!(:dating, 'purple', 'slacks')
   end
 
   it 'should call on_transition with an array of methods' do
     pe.wakeup!(:showering)
-    pe.should_receive(:condition_hair)
-    pe.should_receive(:fix_hair)
+    expect(pe).to receive(:condition_hair)
+    expect(pe).to receive(:fix_hair)
     pe.dress!(:prettying_up)
   end
 end
@@ -274,9 +274,9 @@ describe 'event firing without persistence' do
   it 'should attempt to persist if aasm_write_state is defined' do
     foo = Foo.new
     def foo.aasm_write_state; end
-    foo.should be_open
+    expect(foo).to be_open
 
-    foo.should_receive(:aasm_write_state_without_persistence)
+    expect(foo).to receive(:aasm_write_state_without_persistence)
     foo.close
   end
 end
diff --git a/spec/unit/initial_state_spec.rb b/spec/unit/initial_state_spec.rb
index dcf7fb8..60f7f8c 100644
--- a/spec/unit/initial_state_spec.rb
+++ b/spec/unit/initial_state_spec.rb
@@ -17,11 +17,11 @@ describe 'initial states' do
   let(:bar) {Bar.new}
 
   it 'should use the first state defined if no initial state is given' do
-    bar.aasm.current_state.should == :read
+    expect(bar.aasm.current_state).to eq(:read)
   end
 
   it 'should determine initial state from the Proc results' do
-    Banker.new(Banker::RICH - 1).aasm.current_state.should == :selling_bad_mortgages
-    Banker.new(Banker::RICH + 1).aasm.current_state.should == :retired
+    expect(Banker.new(Banker::RICH - 1).aasm.current_state).to eq(:selling_bad_mortgages)
+    expect(Banker.new(Banker::RICH + 1).aasm.current_state).to eq(:retired)
   end
 end
diff --git a/spec/unit/inspection_spec.rb b/spec/unit/inspection_spec.rb
index 9ac597a..b846d0b 100644
--- a/spec/unit/inspection_spec.rb
+++ b/spec/unit/inspection_spec.rb
@@ -2,16 +2,16 @@ require 'spec_helper'
 
 describe 'inspection for common cases' do
   it 'should support the new DSL' do
-    Foo.aasm.should respond_to(:states)
-    Foo.aasm.states.should include(:open)
-    Foo.aasm.states.should include(:closed)
+    expect(Foo.aasm).to respond_to(:states)
+    expect(Foo.aasm.states).to include(:open)
+    expect(Foo.aasm.states).to include(:closed)
 
-    Foo.aasm.should respond_to(:initial_state)
-    Foo.aasm.initial_state.should == :open
+    expect(Foo.aasm).to respond_to(:initial_state)
+    expect(Foo.aasm.initial_state).to eq(:open)
 
-    Foo.aasm.should respond_to(:events)
-    Foo.aasm.events.should include(:close)
-    Foo.aasm.events.should include(:null)
+    expect(Foo.aasm).to respond_to(:events)
+    expect(Foo.aasm.events).to include(:close)
+    expect(Foo.aasm.events).to include(:null)
   end
 
   context "instance level inspection" do
@@ -20,77 +20,77 @@ describe 'inspection for common cases' do
 
     it "delivers all states" do
       states = foo.aasm.states
-      states.should include(:open)
-      states.should include(:closed)
+      expect(states).to include(:open)
+      expect(states).to include(:closed)
 
       states = foo.aasm.states(:permissible => true)
-      states.should include(:closed)
-      states.should_not include(:open)
+      expect(states).to include(:closed)
+      expect(states).not_to include(:open)
 
       foo.close
-      foo.aasm.states(:permissible => true).should be_empty
+      expect(foo.aasm.states(:permissible => true)).to be_empty
     end
 
     it "delivers all states for subclasses" do
       states = two.aasm.states
-      states.should include(:open)
-      states.should include(:closed)
-      states.should include(:foo)
+      expect(states).to include(:open)
+      expect(states).to include(:closed)
+      expect(states).to include(:foo)
 
       states = two.aasm.states(:permissible => true)
-      states.should include(:closed)
-      states.should_not include(:open)
+      expect(states).to include(:closed)
+      expect(states).not_to include(:open)
 
       two.close
-      two.aasm.states(:permissible => true).should be_empty
+      expect(two.aasm.states(:permissible => true)).to be_empty
     end
 
     it "delivers all events" do
       events = foo.aasm.events
-      events.should include(:close)
-      events.should include(:null)
+      expect(events).to include(:close)
+      expect(events).to include(:null)
       foo.close
-      foo.aasm.events.should be_empty
+      expect(foo.aasm.events).to be_empty
     end
   end
 
   it 'should list states in the order they have been defined' do
-    Conversation.aasm.states.should == [:needs_attention, :read, :closed, :awaiting_response, :junk]
+    expect(Conversation.aasm.states).to eq([:needs_attention, :read, :closed, :awaiting_response, :junk])
   end
 end
 
 describe "special cases" do
   it "should support valid a state name" do
-    Argument.aasm.states.should include(:invalid)
-    Argument.aasm.states.should include(:valid)
+    expect(Argument.aasm.states).to include(:invalid)
+    expect(Argument.aasm.states).to include(:valid)
 
     argument = Argument.new
-    argument.invalid?.should be_true
-    argument.aasm.current_state.should == :invalid
+    expect(argument.invalid?).to be_true
+    expect(argument.aasm.current_state).to eq(:invalid)
 
     argument.valid!
-    argument.valid?.should be_true
-    argument.aasm.current_state.should == :valid
+    expect(argument.valid?).to be_true
+    expect(argument.aasm.current_state).to eq(:valid)
   end
 end
 
 describe 'aasm.states_for_select' do
   it "should return a select friendly array of states" do
-    Foo.aasm.should respond_to(:states_for_select)
-    Foo.aasm.states_for_select.should == [['Open', 'open'], ['Closed', 'closed']]
+    expect(Foo.aasm).to respond_to(:states_for_select)
+    expect(Foo.aasm.states_for_select).to eq([['Open', 'open'], ['Closed', 'closed']])
   end
 end
 
 describe 'aasm.from_states_for_state' do
   it "should return all from states for a state" do
-    AuthMachine.aasm.should respond_to(:from_states_for_state)
+    expect(AuthMachine.aasm).to respond_to(:from_states_for_state)
     froms = AuthMachine.aasm.from_states_for_state(:active)
-    [:pending, :passive, :suspended].each {|from| froms.should include(from)}
+    [:pending, :passive, :suspended].each {|from| expect(froms).to include(from)}
   end
 
   it "should return from states for a state for a particular transition only" do
     froms = AuthMachine.aasm.from_states_for_state(:active, :transition => :unsuspend)
-    [:suspended].each {|from| froms.should include(from)}
+    [:suspended].each {|from| expect(froms).to include(from)}
   end
 end
 
@@ -98,7 +98,7 @@ describe 'permissible events' do
   let(:foo) {Foo.new}
 
   it 'work' do
-    foo.aasm.permissible_events.should include(:close)
-    foo.aasm.permissible_events.should_not include(:null)
+    expect(foo.aasm.permissible_events).to include(:close)
+    expect(foo.aasm.permissible_events).not_to include(:null)
   end
 end
diff --git a/spec/unit/localizer_spec.rb b/spec/unit/localizer_spec.rb
index 6a5719a..07ec504 100644
--- a/spec/unit/localizer_spec.rb
+++ b/spec/unit/localizer_spec.rb
@@ -31,14 +31,14 @@ describe 'localized state names' do
 
   it 'should localize' do
     state = LocalizerTestModel.aasm.states.detect {|s| s == :opened}
-    state.localized_name.should == "It's open now!"
-    state.human_name.should == "It's open now!"
+    expect(state.localized_name).to eq("It's open now!")
+    expect(state.human_name).to eq("It's open now!")
   end
 
   it 'should use fallback' do
     state = LocalizerTestModel.aasm.states.detect {|s| s == :closed}
-    state.localized_name.should == 'Closed'
-    state.human_name.should == 'Closed'
+    expect(state.localized_name).to eq('Closed')
+    expect(state.human_name).to eq('Closed')
   end
 end
 
@@ -58,21 +58,21 @@ describe AASM::Localizer, "new style" do
 
   context 'aasm.human_state' do
     it 'should return translated state value' do
-      foo_opened.aasm.human_state.should == "It's open now!"
+      expect(foo_opened.aasm.human_state).to eq("It's open now!")
     end
 
     it 'should return humanized value if not localized' do
-      foo_closed.aasm.human_state.should == "Closed"
+      expect(foo_closed.aasm.human_state).to eq("Closed")
     end
   end
 
   context 'aasm_human_event_name' do
     it 'should return translated event name' do
-      LocalizerTestModel.aasm_human_event_name(:close).should == "Let's close it!"
+      expect(LocalizerTestModel.aasm_human_event_name(:close)).to eq("Let's close it!")
     end
 
     it 'should return humanized event name' do
-      LocalizerTestModel.aasm_human_event_name(:open).should == "Open"
+      expect(LocalizerTestModel.aasm_human_event_name(:open)).to eq("Open")
     end
   end
 end
@@ -93,21 +93,21 @@ describe AASM::Localizer, "deprecated style" do
 
   context 'aasm.human_state' do
     it 'should return translated state value' do
-      foo_opened.aasm.human_state.should == "It's open now!"
+      expect(foo_opened.aasm.human_state).to eq("It's open now!")
     end
 
     it 'should return humanized value if not localized' do
-      foo_closed.aasm.human_state.should == "Closed"
+      expect(foo_closed.aasm.human_state).to eq("Closed")
     end
   end
 
   context 'aasm_human_event_name' do
     it 'should return translated event name' do
-      LocalizerTestModel.aasm_human_event_name(:close).should == "Let's close it!"
+      expect(LocalizerTestModel.aasm_human_event_name(:close)).to eq("Let's close it!")
     end
 
     it 'should return humanized event name' do
-      LocalizerTestModel.aasm_human_event_name(:open).should == "Open"
+      expect(LocalizerTestModel.aasm_human_event_name(:open)).to eq("Open")
     end
   end
 end
diff --git a/spec/unit/new_dsl_spec.rb b/spec/unit/new_dsl_spec.rb
index a6b8b8c..94904f4 100644
--- a/spec/unit/new_dsl_spec.rb
+++ b/spec/unit/new_dsl_spec.rb
@@ -5,8 +5,8 @@ describe "the new dsl" do
   let(:process) {ProcessWithNewDsl.new}
 
   it 'should not conflict with other event or state methods' do
-    lambda {ProcessWithNewDsl.state}.should raise_error(RuntimeError, "wrong state method")
-    lambda {ProcessWithNewDsl.event}.should raise_error(RuntimeError, "wrong event method")
+    expect {ProcessWithNewDsl.state}.to raise_error(RuntimeError, "wrong state method")
+    expect {ProcessWithNewDsl.event}.to raise_error(RuntimeError, "wrong event method")
   end
 
 end
diff --git a/spec/unit/persistence/active_record_persistence_spec.rb b/spec/unit/persistence/active_record_persistence_spec.rb
index 4560fda..204406f 100644
--- a/spec/unit/persistence/active_record_persistence_spec.rb
+++ b/spec/unit/persistence/active_record_persistence_spec.rb
@@ -9,8 +9,8 @@ load_schema
 
 shared_examples_for "aasm model" do
   it "should include persistence mixins" do
-    klass.included_modules.should be_include(AASM::Persistence::ActiveRecordPersistence)
-    klass.included_modules.should be_include(AASM::Persistence::ActiveRecordPersistence::InstanceMethods)
+    expect(klass.included_modules).to be_include(AASM::Persistence::ActiveRecordPersistence)
+    expect(klass.included_modules).to be_include(AASM::Persistence::ActiveRecordPersistence::InstanceMethods)
   end
 end
 
@@ -18,45 +18,45 @@ describe "instance methods" do
   let(:gate) {Gate.new}
 
   it "should respond to aasm persistence methods" do
-    gate.should respond_to(:aasm_read_state)
-    gate.should respond_to(:aasm_write_state)
-    gate.should respond_to(:aasm_write_state_without_persistence)
+    expect(gate).to respond_to(:aasm_read_state)
+    expect(gate).to respond_to(:aasm_write_state)
+    expect(gate).to respond_to(:aasm_write_state_without_persistence)
   end
 
   it "should return the initial state when new and the aasm field is nil" do
-    gate.aasm.current_state.should == :opened
+    expect(gate.aasm.current_state).to eq(:opened)
   end
 
   it "should return the aasm column when new and the aasm field is not nil" do
     gate.aasm_state = "closed"
-    gate.aasm.current_state.should == :closed
+    expect(gate.aasm.current_state).to eq(:closed)
   end
 
   it "should return the aasm column when not new and the aasm_column is not nil" do
-    gate.stub(:new_record?).and_return(false)
+    allow(gate).to receive(:new_record?).and_return(false)
     gate.aasm_state = "state"
-    gate.aasm.current_state.should == :state
+    expect(gate.aasm.current_state).to eq(:state)
   end
 
   it "should allow a nil state" do
-    gate.stub(:new_record?).and_return(false)
+    allow(gate).to receive(:new_record?).and_return(false)
     gate.aasm_state = nil
-    gate.aasm.current_state.should be_nil
+    expect(gate.aasm.current_state).to be_nil
   end
 
   it "should call aasm_ensure_initial_state on validation before create" do
-    gate.should_receive(:aasm_ensure_initial_state).and_return(true)
+    expect(gate).to receive(:aasm_ensure_initial_state).and_return(true)
     gate.valid?
   end
 
   it "should call aasm_ensure_initial_state before create, even if skipping validations" do
-    gate.should_receive(:aasm_ensure_initial_state).and_return(true)
+    expect(gate).to receive(:aasm_ensure_initial_state).and_return(true)
     gate.save(:validate => false)
   end
 
   it "should not call aasm_ensure_initial_state on validation before update" do
-    gate.stub(:new_record?).and_return(false)
-    gate.should_not_receive(:aasm_ensure_initial_state)
+    allow(gate).to receive(:new_record?).and_return(false)
+    expect(gate).not_to receive(:aasm_ensure_initial_state)
     gate.valid?
   end
 
@@ -64,36 +64,36 @@ end
 
 describe 'subclasses' do
   it "should have the same states as its parent class" do
-    DerivateNewDsl.aasm.states.should == SimpleNewDsl.aasm.states
+    expect(DerivateNewDsl.aasm.states).to eq(SimpleNewDsl.aasm.states)
   end
 
   it "should have the same events as its parent class" do
-    DerivateNewDsl.aasm.events.should == SimpleNewDsl.aasm.events
+    expect(DerivateNewDsl.aasm.events).to eq(SimpleNewDsl.aasm.events)
   end
 
   it "should have the same column as its parent even for the new dsl" do
-    SimpleNewDsl.aasm_column.should == :status
-    DerivateNewDsl.aasm_column.should == :status
+    expect(SimpleNewDsl.aasm_column).to eq(:status)
+    expect(DerivateNewDsl.aasm_column).to eq(:status)
   end
 end
 
 describe "named scopes with the new DSL" do
   context "Does not already respond_to? the scope name" do
     it "should add a scope" do
-      SimpleNewDsl.should respond_to(:unknown_scope)
-      SimpleNewDsl.unknown_scope.is_a?(ActiveRecord::Relation).should be_true
+      expect(SimpleNewDsl).to respond_to(:unknown_scope)
+      expect(SimpleNewDsl.unknown_scope.is_a?(ActiveRecord::Relation)).to be_true
     end
   end
 
   context "Already respond_to? the scope name" do
     it "should not add a scope" do
-      SimpleNewDsl.should respond_to(:new)
-      SimpleNewDsl.new.class.should == SimpleNewDsl
+      expect(SimpleNewDsl).to respond_to(:new)
+      expect(SimpleNewDsl.new.class).to eq(SimpleNewDsl)
     end
   end
 
   it "does not create scopes if requested" do
-    NoScope.should_not respond_to(:ignored_scope)
+    expect(NoScope).not_to respond_to(:ignored_scope)
   end
 
 end
@@ -101,8 +101,8 @@ end
 describe 'initial states' do
 
   it 'should support conditions' do
-    Thief.new(:skilled => true).aasm.current_state.should == :rich
-    Thief.new(:skilled => false).aasm.current_state.should == :jailed
+    expect(Thief.new(:skilled => true).aasm.current_state).to eq(:rich)
+    expect(Thief.new(:skilled => false).aasm.current_state).to eq(:jailed)
   end
 end
 
@@ -110,54 +110,54 @@ describe 'transitions with persistence' do
 
   it "should work for valid models" do
     valid_object = Validator.create(:name => 'name')
-    valid_object.should be_sleeping
+    expect(valid_object).to be_sleeping
     valid_object.status = :running
-    valid_object.should be_running
+    expect(valid_object).to be_running
   end
 
   it 'should not store states for invalid models' do
     validator = Validator.create(:name => 'name')
-    validator.should be_valid
-    validator.should be_sleeping
+    expect(validator).to be_valid
+    expect(validator).to be_sleeping
 
     validator.name = nil
-    validator.should_not be_valid
-    validator.run!.should be_false
-    validator.should be_sleeping
+    expect(validator).not_to be_valid
+    expect(validator.run!).to be_false
+    expect(validator).to be_sleeping
 
     validator.reload
-    validator.should_not be_running
-    validator.should be_sleeping
+    expect(validator).not_to be_running
+    expect(validator).to be_sleeping
 
     validator.name = 'another name'
-    validator.should be_valid
-    validator.run!.should be_true
-    validator.should be_running
+    expect(validator).to be_valid
+    expect(validator.run!).to be_true
+    expect(validator).to be_running
 
     validator.reload
-    validator.should be_running
-    validator.should_not be_sleeping
+    expect(validator).to be_running
+    expect(validator).not_to be_sleeping
   end
 
   it 'should store states for invalid models if configured' do
     persistor = InvalidPersistor.create(:name => 'name')
-    persistor.should be_valid
-    persistor.should be_sleeping
+    expect(persistor).to be_valid
+    expect(persistor).to be_sleeping
 
     persistor.name = nil
-    persistor.should_not be_valid
-    persistor.run!.should be_true
-    persistor.should be_running
+    expect(persistor).not_to be_valid
+    expect(persistor.run!).to be_true
+    expect(persistor).to be_running
 
     persistor = InvalidPersistor.find(persistor.id)
     persistor.valid?
-    persistor.should be_valid
-    persistor.should be_running
-    persistor.should_not be_sleeping
+    expect(persistor).to be_valid
+    expect(persistor).to be_running
+    expect(persistor).not_to be_sleeping
 
     persistor.reload
-    persistor.should be_running
-    persistor.should_not be_sleeping
+    expect(persistor).to be_running
+    expect(persistor).not_to be_sleeping
   end
 
   describe 'transactions' do
@@ -165,39 +165,39 @@ describe 'transitions with persistence' do
     let(:transactor) { Transactor.create!(:name => 'transactor', :worker => worker) }
 
     it 'should rollback all changes' do
-      transactor.should be_sleeping
-      worker.status.should == 'sleeping'
+      expect(transactor).to be_sleeping
+      expect(worker.status).to eq('sleeping')
 
-      lambda {transactor.run!}.should raise_error(StandardError, 'failed on purpose')
-      transactor.should be_running
-      worker.reload.status.should == 'sleeping'
+      expect {transactor.run!}.to raise_error(StandardError, 'failed on purpose')
+      expect(transactor).to be_running
+      expect(worker.reload.status).to eq('sleeping')
     end
 
     it "should rollback all changes in nested transaction" do
-      transactor.should be_sleeping
-      worker.status.should == 'sleeping'
+      expect(transactor).to be_sleeping
+      expect(worker.status).to eq('sleeping')
 
       Worker.transaction do
-        lambda { transactor.run! }.should raise_error(StandardError, 'failed on purpose')
+        expect { transactor.run! }.to raise_error(StandardError, 'failed on purpose')
       end
 
-      transactor.should be_running
-      worker.reload.status.should == 'sleeping'
+      expect(transactor).to be_running
+      expect(worker.reload.status).to eq('sleeping')
     end
 
     describe "after_commit callback" do
       it "should fire :after_commit if transaction was successful" do
         validator = Validator.create(:name => 'name')
-        validator.should be_sleeping
+        expect(validator).to be_sleeping
         validator.run!
-        validator.should be_running
-        validator.name.should_not == "name"
+        expect(validator).to be_running
+        expect(validator.name).not_to eq("name")
       end
 
       it "should not fire :after_commit if transaction failed" do
         validator = Validator.create(:name => 'name')
-        lambda { validator.fail! }.should raise_error(StandardError, 'failed on purpose')
-        validator.name.should == "name"
+        expect { validator.fail! }.to raise_error(StandardError, 'failed on purpose')
+        expect(validator.name).to eq("name")
       end
 
     end
@@ -209,20 +209,20 @@ describe "invalid states with persistence" do
   it "should not store states" do
     validator = Validator.create(:name => 'name')
     validator.status = 'invalid_state'
-    validator.save.should be_false
-    lambda {validator.save!}.should raise_error(ActiveRecord::RecordInvalid)
+    expect(validator.save).to be_false
+    expect {validator.save!}.to raise_error(ActiveRecord::RecordInvalid)
 
     validator.reload
-    validator.should be_sleeping
+    expect(validator).to be_sleeping
   end
 
   it "should store invalid states if configured" do
     persistor = InvalidPersistor.create(:name => 'name')
     persistor.status = 'invalid_state'
-    persistor.save.should be_true
+    expect(persistor.save).to be_true
 
     persistor.reload
-    persistor.status.should == 'invalid_state'
+    expect(persistor.status).to eq('invalid_state')
   end
 
 end
diff --git a/spec/unit/persistence/mongoid_persistance_spec.rb b/spec/unit/persistence/mongoid_persistance_spec.rb
index f214667..5bd490a 100644
--- a/spec/unit/persistence/mongoid_persistance_spec.rb
+++ b/spec/unit/persistence/mongoid_persistance_spec.rb
@@ -27,15 +27,15 @@ describe 'mongoid', :if => Gem::Version.create(RUBY_VERSION.dup) >= Gem::Version
 
       context "Does not already respond_to? the scope name" do
         it "should add a scope" do
-          SimpleMongoid.should respond_to(:unknown_scope)
-          SimpleMongoid.unknown_scope.class.should == Mongoid::Criteria
+          expect(SimpleMongoid).to respond_to(:unknown_scope)
+          expect(SimpleMongoid.unknown_scope.class).to eq(Mongoid::Criteria)
         end
       end
 
       context "Already respond_to? the scope name" do
         it "should not add a scope" do
-          SimpleMongoid.should respond_to(:new)
-          SimpleMongoid.new.class.should == SimpleMongoid
+          expect(SimpleMongoid).to respond_to(:new)
+          expect(SimpleMongoid.new.class).to eq(SimpleMongoid)
         end
       end
 
@@ -45,20 +45,20 @@ describe 'mongoid', :if => Gem::Version.create(RUBY_VERSION.dup) >= Gem::Version
 
       context "Does not already respond_to? the scope name" do
         it "should add a scope" do
-          SimpleNewDslMongoid.should respond_to(:unknown_scope)
-          SimpleNewDslMongoid.unknown_scope.class.should == Mongoid::Criteria
+          expect(SimpleNewDslMongoid).to respond_to(:unknown_scope)
+          expect(SimpleNewDslMongoid.unknown_scope.class).to eq(Mongoid::Criteria)
         end
       end
 
       context "Already respond_to? the scope name" do
         it "should not add a scope" do
-          SimpleNewDslMongoid.should respond_to(:new)
-          SimpleNewDslMongoid.new.class.should == SimpleNewDslMongoid
+          expect(SimpleNewDslMongoid).to respond_to(:new)
+          expect(SimpleNewDslMongoid.new.class).to eq(SimpleNewDslMongoid)
         end
       end
 
       it "does not create scopes if requested" do
-        NoScopeMongoid.should_not respond_to(:ignored_scope)
+        expect(NoScopeMongoid).not_to respond_to(:ignored_scope)
       end
 
     end
@@ -69,12 +69,12 @@ describe 'mongoid', :if => Gem::Version.create(RUBY_VERSION.dup) >= Gem::Version
       let!(:model_id) { model._id }
 
       it "should respond to method" do
-        SimpleNewDslMongoid.should respond_to(:find_in_state)
+        expect(SimpleNewDslMongoid).to respond_to(:find_in_state)
       end
 
       it "should find the model when given the correct scope and model id" do
-        SimpleNewDslMongoid.find_in_state(model_id, 'unknown_scope').class.should == SimpleNewDslMongoid
-        SimpleNewDslMongoid.find_in_state(model_id, 'unknown_scope').should == model
+        expect(SimpleNewDslMongoid.find_in_state(model_id, 'unknown_scope').class).to eq(SimpleNewDslMongoid)
+        expect(SimpleNewDslMongoid.find_in_state(model_id, 'unknown_scope')).to eq(model)
       end
 
       it "should raise DocumentNotFound error when given incorrect scope" do
@@ -94,17 +94,17 @@ describe 'mongoid', :if => Gem::Version.create(RUBY_VERSION.dup) >= Gem::Version
       end
 
       it "should respond to method" do
-        SimpleNewDslMongoid.should respond_to(:count_in_state)
+        expect(SimpleNewDslMongoid).to respond_to(:count_in_state)
       end
 
       it "should return n for a scope with n records persisted" do
-        SimpleNewDslMongoid.count_in_state('unknown_scope').class.should == Fixnum
-        SimpleNewDslMongoid.count_in_state('unknown_scope').should == 3
+        expect(SimpleNewDslMongoid.count_in_state('unknown_scope').class).to eq(Fixnum)
+        expect(SimpleNewDslMongoid.count_in_state('unknown_scope')).to eq(3)
       end
 
       it "should return zero for a scope without records persisted" do
-        SimpleNewDslMongoid.count_in_state('new').class.should == Fixnum
-        SimpleNewDslMongoid.count_in_state('new').should == 0
+        expect(SimpleNewDslMongoid.count_in_state('new').class).to eq(Fixnum)
+        expect(SimpleNewDslMongoid.count_in_state('new')).to eq(0)
       end
 
     end
@@ -117,16 +117,16 @@ describe 'mongoid', :if => Gem::Version.create(RUBY_VERSION.dup) >= Gem::Version
       end
 
       it "should respond to method" do
-        SimpleNewDslMongoid.should respond_to(:with_state_scope)
+        expect(SimpleNewDslMongoid).to respond_to(:with_state_scope)
       end
 
       it "should correctly process block" do
-        SimpleNewDslMongoid.with_state_scope('unknown_scope') do
+        expect(SimpleNewDslMongoid.with_state_scope('unknown_scope') do
           SimpleNewDslMongoid.count
-        end.should == 3
-        SimpleNewDslMongoid.with_state_scope('new') do
+        end).to eq(3)
+        expect(SimpleNewDslMongoid.with_state_scope('new') do
           SimpleNewDslMongoid.count
-        end.should == 2
+        end).to eq(2)
       end
 
     end
@@ -136,12 +136,12 @@ describe 'mongoid', :if => Gem::Version.create(RUBY_VERSION.dup) >= Gem::Version
       let(:simple) {SimpleNewDslMongoid.new}
 
       it "should call aasm_ensure_initial_state on validation before create" do
-        simple.should_receive(:aasm_ensure_initial_state).and_return(true)
+        expect(simple).to receive(:aasm_ensure_initial_state).and_return(true)
         simple.valid?
       end
 
       it "should call aasm_ensure_initial_state before create, even if skipping validations" do
-        simple.should_receive(:aasm_ensure_initial_state).and_return(true)
+        expect(simple).to receive(:aasm_ensure_initial_state).and_return(true)
         simple.save(:validate => false)
       end
     end
diff --git a/spec/unit/simple_example_spec.rb b/spec/unit/simple_example_spec.rb
index 3d88c65..d6ad4d2 100644
--- a/spec/unit/simple_example_spec.rb
+++ b/spec/unit/simple_example_spec.rb
@@ -20,39 +20,39 @@ describe 'state machine' do
   let(:payment) {Payment.new}
 
   it 'starts with an initial state' do
-    payment.aasm.current_state.should == :initialised
-    payment.should respond_to(:initialised?)
-    payment.should be_initialised
+    expect(payment.aasm.current_state).to eq(:initialised)
+    expect(payment).to respond_to(:initialised?)
+    expect(payment).to be_initialised
   end
 
   it 'allows transitions to other states' do
-    payment.should respond_to(:fill_out)
-    payment.should respond_to(:fill_out!)
+    expect(payment).to respond_to(:fill_out)
+    expect(payment).to respond_to(:fill_out!)
     payment.fill_out!
-    payment.should respond_to(:filled_out?)
-    payment.should be_filled_out
+    expect(payment).to respond_to(:filled_out?)
+    expect(payment).to be_filled_out
 
-    payment.should respond_to(:authorise)
-    payment.should respond_to(:authorise!)
+    expect(payment).to respond_to(:authorise)
+    expect(payment).to respond_to(:authorise!)
     payment.authorise
-    payment.should respond_to(:authorised?)
-    payment.should be_authorised
+    expect(payment).to respond_to(:authorised?)
+    expect(payment).to be_authorised
   end
 
   it 'denies transitions to other states' do
-    lambda {payment.authorise}.should raise_error(AASM::InvalidTransition)
-    lambda {payment.authorise!}.should raise_error(AASM::InvalidTransition)
+    expect {payment.authorise}.to raise_error(AASM::InvalidTransition)
+    expect {payment.authorise!}.to raise_error(AASM::InvalidTransition)
     payment.fill_out
-    lambda {payment.fill_out}.should raise_error(AASM::InvalidTransition)
-    lambda {payment.fill_out!}.should raise_error(AASM::InvalidTransition)
+    expect {payment.fill_out}.to raise_error(AASM::InvalidTransition)
+    expect {payment.fill_out!}.to raise_error(AASM::InvalidTransition)
     payment.authorise
-    lambda {payment.fill_out}.should raise_error(AASM::InvalidTransition)
-    lambda {payment.fill_out!}.should raise_error(AASM::InvalidTransition)
+    expect {payment.fill_out}.to raise_error(AASM::InvalidTransition)
+    expect {payment.fill_out!}.to raise_error(AASM::InvalidTransition)
   end
 
   it 'defines constants for each state name' do
-    Payment::STATE_INITIALISED.should eq(:initialised)
-    Payment::STATE_FILLED_OUT.should eq(:filled_out)
-    Payment::STATE_AUTHORISED.should eq(:authorised)
+    expect(Payment::STATE_INITIALISED).to eq(:initialised)
+    expect(Payment::STATE_FILLED_OUT).to eq(:filled_out)
+    expect(Payment::STATE_AUTHORISED).to eq(:authorised)
   end
 end
diff --git a/spec/unit/state_spec.rb b/spec/unit/state_spec.rb
index 30f2b9a..ce85c1a 100644
--- a/spec/unit/state_spec.rb
+++ b/spec/unit/state_spec.rb
@@ -12,34 +12,34 @@ describe AASM::State do
 
   it 'should set the name' do
     state = new_state
-    state.name.should == :astate
+    expect(state.name).to eq(:astate)
   end
 
   it 'should set the display_name from name' do
-    new_state.display_name.should == 'Astate'
+    expect(new_state.display_name).to eq('Astate')
   end
 
   it 'should set the display_name from options' do
-    new_state(:display => "A State").display_name.should == 'A State'
+    expect(new_state(:display => "A State").display_name).to eq('A State')
   end
 
   it 'should set the options and expose them as options' do
-    new_state.options.should == @options
+    expect(new_state.options).to eq(@options)
   end
 
   it 'should be equal to a symbol of the same name' do
-    new_state.should == :astate
+    expect(new_state).to eq(:astate)
   end
 
   it 'should be equal to a State of the same name' do
-    new_state.should == new_state
+    expect(new_state).to eq(new_state)
   end
 
   it 'should send a message to the record for an action if the action is present as a symbol' do
     state = new_state(:entering => :foo)
 
     record = double('record')
-    record.should_receive(:foo)
+    expect(record).to receive(:foo)
 
     state.fire_callbacks(:entering, record)
   end
@@ -48,7 +48,7 @@ describe AASM::State do
     state = new_state(:entering => 'foo')
 
     record = double('record')
-    record.should_receive(:foo)
+    expect(record).to receive(:foo)
 
     state.fire_callbacks(:entering, record)
   end
@@ -57,10 +57,10 @@ describe AASM::State do
     state = new_state(:entering => [:a, :b, "c", lambda {|r| r.foobar }])
 
     record = double('record')
-    record.should_receive(:a)
-    record.should_receive(:b)
-    record.should_receive(:c)
-    record.should_receive(:foobar)
+    expect(record).to receive(:a)
+    expect(record).to receive(:b)
+    expect(record).to receive(:c)
+    expect(record).to receive(:foobar)
 
     state.fire_callbacks(:entering, record)
   end
@@ -69,9 +69,9 @@ describe AASM::State do
     state = new_state(:entering => [:a, :b, :c])
 
     record = double('record')
-    record.should_receive(:a)
-    record.should_receive(:b).and_throw(:halt_aasm_chain)
-    record.should_not_receive(:c)
+    expect(record).to receive(:a)
+    expect(record).to receive(:b).and_throw(:halt_aasm_chain)
+    expect(record).not_to receive(:c)
 
     state.fire_callbacks(:entering, record)
   end
@@ -80,7 +80,7 @@ describe AASM::State do
     state = new_state(:entering => Proc.new {|r| r.foobar})
 
     record = double('record')
-    record.should_receive(:foobar)
+    expect(record).to receive(:foobar)
 
     state.fire_callbacks(:entering, record)
   end
diff --git a/spec/unit/subclassing_spec.rb b/spec/unit/subclassing_spec.rb
index a2d6602..356e5a0 100644
--- a/spec/unit/subclassing_spec.rb
+++ b/spec/unit/subclassing_spec.rb
@@ -5,26 +5,26 @@ describe 'subclassing' do
 
   it 'should have the parent states' do
     Foo.aasm.states.each do |state|
-      FooTwo.aasm.states.should include(state)
+      expect(FooTwo.aasm.states).to include(state)
     end
-    Baz.aasm.states.should == Bar.aasm.states
+    expect(Baz.aasm.states).to eq(Bar.aasm.states)
   end
 
   it 'should not add the child states to the parent machine' do
-    Foo.aasm.states.should_not include(:foo)
+    expect(Foo.aasm.states).not_to include(:foo)
   end
 
   it "should have the same events as its parent" do
-    Baz.aasm.events.should == Bar.aasm.events
+    expect(Baz.aasm.events).to eq(Bar.aasm.events)
   end
 
   it 'should know how to respond to `may_add_details?`' do
-    son.may_add_details?.should be_true
+    expect(son.may_add_details?).to be_true
   end
 
   it 'should not break if I call Son#update_state' do
     son.update_state
-    son.aasm.current_state.should == :pending_details_confirmation
+    expect(son.aasm.current_state).to eq(:pending_details_confirmation)
   end
 
 end
diff --git a/spec/unit/transition_spec.rb b/spec/unit/transition_spec.rb
index f0444e0..5561d28 100644
--- a/spec/unit/transition_spec.rb
+++ b/spec/unit/transition_spec.rb
@@ -4,46 +4,46 @@ describe 'transitions' do
 
   it 'should raise an exception when whiny' do
     process = ProcessWithNewDsl.new
-    lambda { process.stop! }.should raise_error(AASM::InvalidTransition)
-    process.should be_sleeping
+    expect { process.stop! }.to raise_error(AASM::InvalidTransition)
+    expect(process).to be_sleeping
   end
 
   it 'should not raise an exception when not whiny' do
     silencer = Silencer.new
-    silencer.smile!.should be_false
-    silencer.should be_silent
+    expect(silencer.smile!).to be_false
+    expect(silencer).to be_silent
   end
 
   it 'should not raise an exception when superclass not whiny' do
     sub = SubClassing.new
-    sub.smile!.should be_false
-    sub.should be_silent
+    expect(sub.smile!).to be_false
+    expect(sub).to be_silent
   end
 
   it 'should not raise an exception when from is nil even if whiny' do
     silencer = Silencer.new
-    silencer.smile_any!.should be_true
-    silencer.should be_smiling
+    expect(silencer.smile_any!).to be_true
+    expect(silencer).to be_smiling
   end
 
   it 'should call the block when success' do
     silencer = Silencer.new
     success = false
-    lambda {
+    expect {
       silencer.smile_any! do
         success = true
       end
-    }.should change { success }.to(true)
+    }.to change { success }.to(true)
   end
 
   it 'should not call the block when failure' do
     silencer = Silencer.new
     success = false
-    lambda {
+    expect {
       silencer.smile! do
         success = true
       end
-    }.should_not change { success }.to(true)
+    }.not_to change { success }.to(true)
   end
 
 end
@@ -56,9 +56,9 @@ describe AASM::Transition do
     opts = {:from => 'foo', :to => 'bar', :guard => 'g'}
     st = AASM::Transition.new(opts)
 
-    st.from.should == opts[:from]
-    st.to.should == opts[:to]
-    st.opts.should == opts
+    expect(st.from).to eq(opts[:from])
+    expect(st.to).to eq(opts[:to])
+    expect(st.opts).to eq(opts)
   end
 
   it 'should pass equality check if from and to are the same' do
@@ -66,10 +66,10 @@ describe AASM::Transition do
     st = AASM::Transition.new(opts)
 
     obj = double('object')
-    obj.stub(:from).and_return(opts[:from])
-    obj.stub(:to).and_return(opts[:to])
+    allow(obj).to receive(:from).and_return(opts[:from])
+    allow(obj).to receive(:to).and_return(opts[:to])
 
-    st.should == obj
+    expect(st).to eq(obj)
   end
 
   it 'should fail equality check if from are not the same' do
@@ -77,10 +77,10 @@ describe AASM::Transition do
     st = AASM::Transition.new(opts)
 
     obj = double('object')
-    obj.stub(:from).and_return('blah')
-    obj.stub(:to).and_return(opts[:to])
+    allow(obj).to receive(:from).and_return('blah')
+    allow(obj).to receive(:to).and_return(opts[:to])
 
-    st.should_not == obj
+    expect(st).not_to eq(obj)
   end
 
   it 'should fail equality check if to are not the same' do
@@ -88,10 +88,10 @@ describe AASM::Transition do
     st = AASM::Transition.new(opts)
 
     obj = double('object')
-    obj.stub(:from).and_return(opts[:from])
-    obj.stub(:to).and_return('blah')
+    allow(obj).to receive(:from).and_return(opts[:from])
+    allow(obj).to receive(:to).and_return('blah')
 
-    st.should_not == obj
+    expect(st).not_to eq(obj)
   end
 end
 
@@ -100,7 +100,7 @@ describe AASM::Transition, '- when performing guard checks' do
     opts = {:from => 'foo', :to => 'bar'}
     st = AASM::Transition.new(opts)
 
-    st.perform(nil).should be_true
+    expect(st.perform(nil)).to be_true
   end
 
   it 'should call the method on the object if guard is a symbol' do
@@ -108,7 +108,7 @@ describe AASM::Transition, '- when performing guard checks' do
     st = AASM::Transition.new(opts)
 
     obj = double('object')
-    obj.should_receive(:test)
+    expect(obj).to receive(:test)
 
     st.perform(obj)
   end
@@ -118,7 +118,7 @@ describe AASM::Transition, '- when performing guard checks' do
     st = AASM::Transition.new(opts)
 
     obj = double('object')
-    obj.should_receive(:test)
+    expect(obj).to receive(:test)
 
     st.perform(obj)
   end
@@ -128,7 +128,7 @@ describe AASM::Transition, '- when performing guard checks' do
     st = AASM::Transition.new(opts)
 
     obj = double('object')
-    obj.should_receive(:test)
+    expect(obj).to receive(:test)
 
     st.perform(obj)
   end
@@ -141,7 +141,7 @@ describe AASM::Transition, '- when executing the transition with a Proc' do
     args = {:arg1 => '1', :arg2 => '2'}
     obj = double('object')
 
-    opts[:on_transition].should_receive(:call).with(any_args)
+    expect(opts[:on_transition]).to receive(:call).with(any_args)
 
     st.execute(obj, args)
   end
@@ -152,7 +152,7 @@ describe AASM::Transition, '- when executing the transition with a Proc' do
     args = {:arg1 => '1', :arg2 => '2'}
     obj = double('object')
 
-    opts[:on_transition].should_receive(:call).with(no_args)
+    expect(opts[:on_transition]).to receive(:call).with(no_args)
 
     st.execute(obj, args)
   end
@@ -165,7 +165,7 @@ describe AASM::Transition, '- when executing the transition with an :on_transtio
     args = {:arg1 => '1', :arg2 => '2'}
     obj = double('object')
 
-    obj.should_receive(:test)
+    expect(obj).to receive(:test)
 
     st.execute(obj, args)
   end
@@ -176,7 +176,7 @@ describe AASM::Transition, '- when executing the transition with an :on_transtio
     args = {:arg1 => '1', :arg2 => '2'}
     obj = double('object')
 
-    obj.should_receive(:test)
+    expect(obj).to receive(:test)
 
     st.execute(obj, args)
   end
@@ -193,7 +193,7 @@ describe AASM::Transition, '- when executing the transition with an :on_transtio
 
     return_value = st.execute(obj, args)
 
-    return_value.should == 'arg1: 1 arg2: 2'
+    expect(return_value).to eq('arg1: 1 arg2: 2')
   end
 
   it 'should NOT pass args if the target method does NOT accept them' do
@@ -208,7 +208,7 @@ describe AASM::Transition, '- when executing the transition with an :on_transtio
 
     return_value = st.execute(obj, args)
 
-    return_value.should == 'success'
+    expect(return_value).to eq('success')
   end
 
 end