Raise an error if should/should_not !=/!~ is used since these operato…

…rs cannot be supported on ruby 1.8.

- Closes #33.

lib/rspec/matchers/operator_matcher.rb

@@ -29,6 +29,15 @@ def self.use_custom_matcher_or_delegate(operator)
             eval_match(@actual, operator, expected)
           end
         end
+
+        negative_operator = operator.sub(/^=/, '!')
+        if negative_operator != operator && respond_to?(negative_operator)
+          define_method(negative_operator) do |expected|
+            opposite_should = ::RSpec::Matchers.last_should == :should ? :should_not : :should
+            raise "RSpec does not support `#{::RSpec::Matchers.last_should} #{negative_operator} expected`.  " +
+                  "Use `#{opposite_should} #{operator} expected` instead."
+          end
+        end
       end
 
       ['==', '===', '=~', '>', '>=', '<', '<='].each do |operator|

spec/rspec/matchers/operator_matcher_spec.rb

@@ -21,6 +21,32 @@
 
 end
 
+describe "unsupported operators", :ruby => '1.9' do
+  it "raises an appropriate error for should != expected" do
+    expect {
+      "apple".should != "pear"
+    }.to raise_error(/does not support `should != expected`.  Use `should_not == expected`/)
+  end
+
+  it "raises an appropriate error for should_not != expected" do
+    expect {
+      "apple".should_not != "pear"
+    }.to raise_error(/does not support `should_not != expected`.  Use `should == expected`/)
+  end
+
+  it "raises an appropriate error for should !~ expected" do
+    expect {
+      "apple".should !~ /regex/
+    }.to raise_error(/does not support `should !~ expected`.  Use `should_not =~ expected`/)
+  end
+
+  it "raises an appropriate error for should_not !~ expected" do
+    expect {
+      "apple".should_not !~ /regex/
+    }.to raise_error(/does not support `should_not !~ expected`.  Use `should =~ expected`/)
+  end
+end
+
 describe "should_not ==" do
 
   it "delegates message to target" do

spec/spec_helper.rb

@@ -49,5 +49,17 @@ def fail_with(message)
   config.include RSpec::Mocks::Methods
   config.color_enabled = true
   config.filter_run :focused => true
+
+  config.filter_run_excluding :ruby => lambda {|version|
+    case version.to_s
+    when "!jruby"
+      RUBY_ENGINE != "jruby"
+    when /^> (.*)/
+      !(RUBY_VERSION.to_s > $1)
+    else
+      !(RUBY_VERSION.to_s =~ /^#{version.to_s}/)
+    end
+  }
+
   config.run_all_when_everything_filtered = true
 end