1 files changed, 56 insertions, 0 deletions
diff --git a/spec/mspec/lib/mspec/matchers/complain.rb b/spec/mspec/lib/mspec/matchers/complain.rb
new file mode 100644
index 0000000000..1313215156
--- /dev/null
+++ b/spec/mspec/lib/mspec/matchers/complain.rb
@@ -0,0 +1,56 @@
+require 'mspec/helpers/io'
+
+class ComplainMatcher
+  def initialize(complaint)
+    @complaint = complaint
+  end
+
+  def matches?(proc)
+    @saved_err = $stderr
+    @stderr = $stderr = IOStub.new
+    @verbose = $VERBOSE
+    $VERBOSE = false
+
+    proc.call
+
+    unless @complaint.nil?
+      case @complaint
+      when Regexp
+        return false unless $stderr =~ @complaint
+      else
+        return false unless $stderr == @complaint
+      end
+    end
+
+    return $stderr.empty? ? false : true
+  ensure
+    $VERBOSE = @verbose
+    $stderr = @saved_err
+  end
+
+  def failure_message
+    if @complaint.nil?
+      ["Expected a warning", "but received none"]
+    elsif @complaint.kind_of? Regexp
+      ["Expected warning to match: #{@complaint.inspect}", "but got: #{@stderr.chomp.inspect}"]
+    else
+      ["Expected warning: #{@complaint.inspect}", "but got: #{@stderr.chomp.inspect}"]
+    end
+  end
+
+  def negative_failure_message
+    if @complaint.nil?
+      ["Unexpected warning: ", @stderr.chomp.inspect]
+    elsif @complaint.kind_of? Regexp
+      ["Expected warning not to match: #{@complaint.inspect}", "but got: #{@stderr.chomp.inspect}"]
+    else
+      ["Expected warning: #{@complaint.inspect}", "but got: #{@stderr.chomp.inspect}"]
+    end
+  end
+end
+
+class Object
+  def complain(complaint=nil)
+    ComplainMatcher.new(complaint)
+  end
+end