lib/rantly/property.rb in rantly-0.3.1 vs lib/rantly/property.rb in rantly-0.3.2

@@ -1,60 +1,82 @@
 require 'rantly'
-require 'test/unit'
 require 'pp'
+require 'stringio'
 
 class Rantly::Property
+  attr_reader :failed_data, :shrunk_failed_data, :io
 
+  VERBOSITY = ENV.fetch('RANTLY_VERBOSE'){ 1 }.to_i
+
+  def io
+    @io ||= if VERBOSITY >= 1
+              STDOUT
+            else
+              StringIO.new
+            end
+  end
+
+  def pretty_print(object)
+    PP.pp(object, io)
+  end
+
   def initialize(property)
     @property = property
   end
-  
+
   def check(n=100,limit=10,&assertion)
     i = 0
     test_data = nil
     begin
       Rantly.singleton.generate(n,limit,@property) do |val|
         test_data = val
         assertion.call(val) if assertion
-        puts "" if i % 100 == 0
-        print "." if i % 10 == 0
+        io.puts "" if i % 100 == 0
+        io.print "." if i % 10 == 0
         i += 1
       end
-      puts
-      puts "success: #{i} tests"
+      io.puts
+      io.puts "success: #{i} tests"
     rescue Rantly::TooManyTries => e
-      puts
-      puts "too many tries: #{e.tries}"
+      io.puts
+      io.puts "too many tries: #{e.tries}"
       raise e
-    rescue => boom
-      puts
-      puts "failure: #{i} tests, on:"
-      pp test_data
+    rescue Exception => boom
+      io.puts
+      io.puts "failure: #{i} tests, on:"
+      pretty_print test_data
+      @failed_data = test_data
+      if @failed_data.respond_to?(:shrink)
+        @shrunk_failed_data = shrinkify(assertion, @failed_data)
+        io.puts "minimal failed data is:"
+        pretty_print @shrunk_failed_data
+      end
       raise boom
     end
   end
 
+  # return the first success case
+  def shrinkify(assertion, data)
+    # We assume that data.shrink is non-destructive
+    return data if !data.shrinkable?
+    val = data.shrink
+    begin
+      assertion.call(val)
+      io.puts "found a reduced success:"
+      pretty_print val
+      return data
+    rescue Exception
+      io.puts "found a reduced failure case:"
+      pretty_print val
+      # recursively shrink failure case
+      return shrinkify(assertion,val)
+    end
+  end
+
   def report
     distribs = self.classifiers.sort { |a,b| b[1] <=> a[1] }
     total = distribs.inject(0) { |sum,pair| sum + pair[1]}
     distribs.each do |(classifier,count)|
       format "%10.5f%% of => %s", count, classifier
     end
   end
-end
-
-module Test::Unit::Assertions
-  def property_of(&block)
-    Rantly::Property.new(block)
-  end
-end
-
-begin
-  require 'rspec'
-  class RSpec::Core::ExampleGroup
-    def property_of(&block)
-      Rantly::Property.new(block)
-    end
-  end
-rescue LoadError
-  "No RSpec loaded. Oh, well."
 end