Add emit of naked guard body

[fixes #280]

lib/mutant/mutator/node/if.rb

@@ -47,6 +47,7 @@ def mutate_condition
         def mutate_if_branch
           emit_type(condition, else_branch, nil) if else_branch
           return unless if_branch
+          emit(if_branch)
           emit_if_branch_mutations
           emit_type(condition, if_branch, nil)
         end
@@ -59,6 +60,7 @@ def mutate_if_branch
         #
         def mutate_else_branch
           return unless else_branch
+          emit(else_branch)
           emit_else_branch_mutations
           emit_type(condition, nil, else_branch)
         end

meta/if.rb

@@ -14,6 +14,12 @@
   # Deleted else branch
   mutation 'if condition; true end'
 
+  # Promote if branch
+  mutation 'true'
+
+  # Promote else branch
+  mutation 'false'
+
   # Deleted if branch resulting in unless rendering
   mutation 'unless condition; false; end'
 
@@ -39,6 +45,7 @@
   mutation 'if true;       true;  end'
   mutation 'if false;      true;  end'
   mutation 'if nil;        true;  end'
+  mutation 'true'
 end
 
 Mutant::Meta::Example.add do
@@ -52,4 +59,5 @@
   mutation 'unless condition;  false; end'
   mutation 'unless condition;  nil;   end'
   mutation 'if     condition;  true;  end'
+  mutation 'true'
 end

meta/match_current_line.rb

@@ -11,4 +11,5 @@
   mutation 'true if false'
   mutation 'true if nil'
   mutation 'true if /a\A/'
+  mutation 'true'
 end