From 85061dee96ff82efce3df8723093581357256ae9 Mon Sep 17 00:00:00 2001
From: Markus Schirp <mbj@schirp-dso.com>
Date: Tue, 22 Apr 2014 18:59:38 +0000
Subject: [PATCH] Add warning expecatation filter for undef initialize

* Closes #175
---
 Changelog.md                                  |  4 +-
 lib/mutant/mutation.rb                        |  4 +-
 lib/mutant/subject/method/instance.rb         | 10 ++++-
 .../mutant/subject/method/instance_spec.rb    | 37 +++++++++++++++++--
 4 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/Changelog.md b/Changelog.md
index c8c127b3..73e58e38 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,4 +1,4 @@
-# v0.5.11 2014-04-xx
+# v0.5.11 2014-04-21
 
 Changes:
 
@@ -6,6 +6,8 @@ Changes:
 * Better require highjack based zombifier
 * Do not mutate nthref $1 to gvar $0
 * Use faster duplicate guarding hashing AST::Node intances
+* Fix lots of shadowed invalid ASTs
+* Fix undefine initialize warnings, Closes #175
 
 # v0.5.10 2014-04-06
 
diff --git a/lib/mutant/mutation.rb b/lib/mutant/mutation.rb
index 69f86784..bd136dac 100644
--- a/lib/mutant/mutation.rb
+++ b/lib/mutant/mutation.rb
@@ -43,7 +43,9 @@ module Mutant
     #
     def insert
       subject.public?
-      Loader::Eval.call(root, subject)
+      subject.warning_expectation.execute do
+        Loader::Eval.call(root, subject)
+      end
       self
     end
 
diff --git a/lib/mutant/subject/method/instance.rb b/lib/mutant/subject/method/instance.rb
index cceb4124..8b6bdd6a 100644
--- a/lib/mutant/subject/method/instance.rb
+++ b/lib/mutant/subject/method/instance.rb
@@ -31,7 +31,15 @@ module Mutant
         # @api private
         #
         def prepare
-          scope.send(:undef_method, name)
+          expected_warnings =
+            if name.equal?(:initialize)
+              ["#{__FILE__}:#{__LINE__ + 5}: warning: undefining `initialize' may cause serious problems\n"]
+            else
+              []
+            end
+          WarningExpectation.new(expected_warnings).execute do
+            scope.send(:undef_method, name)
+          end
           self
         end
 
diff --git a/spec/unit/mutant/subject/method/instance_spec.rb b/spec/unit/mutant/subject/method/instance_spec.rb
index 344e3d88..679b8250 100644
--- a/spec/unit/mutant/subject/method/instance_spec.rb
+++ b/spec/unit/mutant/subject/method/instance_spec.rb
@@ -20,6 +20,12 @@ describe Mutant::Subject::Method::Instance do
 
     let(:scope) do
       Class.new do
+        attr_reader :bar
+
+        def initialize
+          @bar = :boo
+        end
+
         def foo
         end
       end
@@ -27,11 +33,36 @@ describe Mutant::Subject::Method::Instance do
 
     subject { object.prepare }
 
-    it 'undefines method on scope' do
-      expect { subject }.to change { scope.instance_methods.include?(:foo) }.from(true).to(false)
+    context 'on non initialize methods' do
+
+      it 'undefines method on scope' do
+        expect { subject }.to change { scope.instance_methods.include?(:foo) }.from(true).to(false)
+      end
+
+      it_should_behave_like 'a command method'
+
     end
 
-    it_should_behave_like 'a command method'
+    context 'on initialize method' do
+
+      let(:node) do
+        s(:def, :initialize, s(:args))
+      end
+
+      it 'does not write warnings' do
+        warnings = Mutant::WarningFilter.use do
+          subject
+        end
+        expect(warnings).to eql([])
+      end
+
+      it 'undefines method on scope' do
+        subject
+        expect { scope.new }.to raise_error(NoMethodError)
+      end
+
+      it_should_behave_like 'a command method'
+    end
   end
 
   describe '#source' do