From 05331a0ab374b293e41800f8f74d38d431e8444c Mon Sep 17 00:00:00 2001
From: Markus Schirp <mbj@schirp-dso.com>
Date: Sat, 24 May 2014 12:45:38 +0000
Subject: [PATCH] Emit item promotion in case literal array has only one item

Closes #113
---
 Changelog.md                                  |  1 +
 config/flay.yml                               |  2 +-
 lib/mutant/mutator/node/literal/array.rb      |  3 ++
 .../mutant/mutator/node/literal/array_spec.rb | 54 ++++++++++++-------
 4 files changed, 41 insertions(+), 19 deletions(-)

diff --git a/Changelog.md b/Changelog.md
index d6a45645..07f64ded 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -2,6 +2,7 @@
 
 Changes:
 
+* Add mutation from [item] to item
 * Add mutation from #reverse_each to #each
 * Add mutation from #reverse_map to #each, #map
 * Add mutation from #map to #each
diff --git a/config/flay.yml b/config/flay.yml
index adb02e8a..7a366f06 100644
--- a/config/flay.yml
+++ b/config/flay.yml
@@ -1,3 +1,3 @@
 ---
 threshold: 18
-total_score: 791
+total_score: 794
diff --git a/lib/mutant/mutator/node/literal/array.rb b/lib/mutant/mutator/node/literal/array.rb
index c95ec2ca..2a5ef5e2 100644
--- a/lib/mutant/mutator/node/literal/array.rb
+++ b/lib/mutant/mutator/node/literal/array.rb
@@ -21,6 +21,9 @@ module Mutant
             emit_nil
             emit_self
             mutate_body
+            if children.one?
+              emit(children.first)
+            end
           end
 
           # Mutate body
diff --git a/spec/unit/mutant/mutator/node/literal/array_spec.rb b/spec/unit/mutant/mutator/node/literal/array_spec.rb
index 32798e69..07a213d8 100644
--- a/spec/unit/mutant/mutator/node/literal/array_spec.rb
+++ b/spec/unit/mutant/mutator/node/literal/array_spec.rb
@@ -3,27 +3,45 @@
 require 'spec_helper'
 
 describe Mutant::Mutator::Node::Literal, 'array' do
-  let(:source) { '[true, false]' }
 
-  let(:mutations) do
-    mutations = []
+  context 'on one item' do
+    let(:source) { '[true]' }
 
-    # Literal replaced with nil
-    mutations << 'nil'
+    let(:mutations) do
+      mutations = []
+      mutations << 'nil'
+      mutations << 'true'
+      mutations << '[false]'
+      mutations << '[nil]'
+      mutations << '[]'
+    end
 
-    # Mutation of each element in array
-    mutations << '[nil, false]'
-    mutations << '[false, false]'
-    mutations << '[true, nil]'
-    mutations << '[true, true]'
-
-    # Remove each element of array once
-    mutations << '[true]'
-    mutations << '[false]'
-
-    # Empty array
-    mutations << '[]'
+    it_should_behave_like 'a mutator'
   end
 
-  it_should_behave_like 'a mutator'
+  context 'on arrays with more than one item' do
+    let(:source) { '[true, false]' }
+
+    let(:mutations) do
+      mutations = []
+
+      # Literal replaced with nil
+      mutations << 'nil'
+
+      # Mutation of each element in array
+      mutations << '[nil, false]'
+      mutations << '[false, false]'
+      mutations << '[true, nil]'
+      mutations << '[true, true]'
+
+      # Remove each element of array once
+      mutations << '[true]'
+      mutations << '[false]'
+
+      # Empty array
+      mutations << '[]'
+    end
+
+    it_should_behave_like 'a mutator'
+  end
 end