Add support to reset trained classifiers to their initial state (#143)

* Fixed test failutres if redis is not running

* Remove warnings of uninitialized instances of test teardown

* Checking right conditiones for the test teardown

* Added reset methods in Bayes, LSI, and Bayes backends

* Corrected teardown conditionals

* Added tests for reset functionality

* Corrected typo in documentation

* Added tests for reset method in backends

* Utilize Redis backend reset method in test teardown

test/backends/backend_common_tests.rb

@@ -2,9 +2,9 @@
 
 module BackendCommonTests
   def test_initial_values
-    assert_equal 0, @backend.total_words
-    assert_equal 0, @backend.total_trainings
-    assert_equal [], @backend.category_keys
+    assert @backend.total_words.zero?
+    assert @backend.total_trainings.zero?
+    assert @backend.category_keys.empty?
   end
 
   def test_total_words
@@ -55,4 +55,16 @@ def test_category_word_frequency
     @backend.delete_category_word(:Interesting, "foo")
     refute @backend.word_in_category?(:Interesting, "foo")
   end
+
+  def test_reset
+    @backend.update_total_words(10)
+    @backend.update_total_trainings(10)
+    @backend.add_category(:Interesting)
+    @backend.update_category_training_count(:Interesting, 10)
+    @backend.update_category_word_count(:Interesting, 10)
+    @backend.reset
+    assert @backend.total_words.zero?
+    assert @backend.total_trainings.zero?
+    assert @backend.category_keys.empty?
+  end
 end

test/backends/backend_redis_test.rb

@@ -16,6 +16,6 @@ def setup
   end
 
   def teardown
-    @backend.instance_variable_get(:@redis).flushdb if defined? @backend
+    @backend.reset if defined? @backend
   end
 end

test/bayes/bayesian_integration_test.rb

@@ -26,7 +26,7 @@ def setup
   end
 
   def teardown
-    @redis_backend.instance_variable_get(:@redis).flushdb unless @redis_backend.nil?
+    @redis_backend.reset unless @redis_backend.nil?
   end
 
   def test_equality_of_backends

test/bayes/bayesian_redis_benchmark.rb

@@ -32,7 +32,7 @@ def setup
   def teardown
     if defined? @classifiers
       self.class.bench_range.each do |n|
-        @classifiers[n].instance_variable_get(:@backend).instance_variable_get(:@redis).flushdb
+        @classifiers[n].reset
       end
     end
   end

test/bayes/bayesian_redis_test.rb

@@ -21,8 +21,8 @@ def setup
   def teardown
     Hasher::STOPWORDS['en'] = @old_stopwords
     if defined? @backend
-      @backend.instance_variable_get(:@redis).flushdb
-      @alternate_backend.instance_variable_get(:@redis).flushdb
+      @backend.reset
+      @alternate_backend.reset
     end
   end
 end