Not !~, but .not =~.

test/test_commands/test_ls.rb

@@ -64,8 +64,8 @@ describe "ls" do
   describe 'with -l' do
     it 'should find locals and sort by descending size' do
       result = pry_eval("aa = 'asdf'; bb = 'xyz'", 'ls -l')
-      result.should !~ /=>/
-      result.should !~ /0x\d{5}/
+      result.should.not =~ /=>/
+      result.should.not =~ /0x\d{5}/
       result.should =~ /asdf.*xyz/m
     end
     it 'should not list pry noise' do

test/test_pry_output.rb

@@ -37,7 +37,7 @@ describe Pry do
     it 'should have a milder-mannered companion without the hashrocket' do
       s = StringIO.new
       Pry.format_for_output s, '2', :hashrocket => false
-      s.string.should !~ /^=>/
+      s.string.should.not =~ /^=>/
     end
 
     it "should not be phased by un-inspectable things" do