Fixed history and added tests for it

Rakefile

@@ -0,0 +1,3 @@
+task :test do
+  ruby "test/run_all.rb"
+end

lib/coolline/history.rb

@@ -1,4 +1,6 @@
 class Coolline
+  # Class used to keep track of input. It keeps a certain amount of lines at
+  # most in memory, and stores them in a file.
   class History
     def initialize(filename, max_size = 5000)
       @io       = File.open(filename, 'a+')
@@ -22,7 +24,7 @@ def close
     end
 
     def search(pattern, first_line = -1)
-      return to_enum(:search, pattern) unless block_given?
+      return to_enum(:search, pattern, first_line) unless block_given?
       return if size == 0
 
       first_line %= size
@@ -36,7 +38,7 @@ def <<(el)
       @io.flush
 
       @lines << el.dup
-      @lines.unshift if size > @max_size
+      @lines.delete_at(0) if @lines.size > @max_size
 
       self
     end
@@ -53,16 +55,15 @@ def size
 
     private
     def load_lines
-      @io.seek 0, IO::SEEK_END
-      line_count = @io.lineno
-      byte_index = @io.pos
+      line_count = @io.count
       @io.rewind
 
       if line_count < @max_size
-        @lines = @io.lines.map(&:chomp)
+        @lines.concat @io.lines.map(&:chomp)
       else
         @io.each do |line| # surely inefficient
-          self << line.chomp
+          @lines << line.chomp
+          @lines.delete_at(0) if @lines.size > @max_size
         end
       end
     end

test/helpers.rb

@@ -0,0 +1,12 @@
+$LOAD_PATH.unshift File.expand_path(File.join("../lib"), File.dirname(__FILE__))
+
+require 'riot'
+require 'coolline'
+
+Riot.reporter = Riot::PrettyDotMatrixReporter
+
+TestDir = File.dirname(__FILE__)
+
+def path_to(file)
+  File.join(TestDir, file)
+end

test/history_test.rb

@@ -0,0 +1,85 @@
+require File.expand_path("helpers.rb", File.dirname(__FILE__))
+
+context "a newly created history" do
+  setup do
+    Coolline::History.new(path_to("history"), 10)
+  end
+
+  asserts(:size).equals 0
+  asserts(:max_size).equals 10
+
+  context "after inserting a new-line" do
+    hookup do
+      topic << "1"
+    end
+
+    asserts(:size).equals 1
+    asserts(:max_size).equals 10
+
+    asserts(:[], 0).equals "1"
+
+    context "and many others" do
+      hookup do
+        2.upto(11) { |n| topic << n.to_s }
+      end
+
+      asserts(:size).equals 10
+      asserts(:max_size).equals 10
+
+      2.upto(11) do |n|
+        asserts(:[], n - 2).equals n.to_s
+      end
+    end
+  end
+
+  teardown do
+    File.delete path_to("history")
+  end
+end
+
+context "an history from an existing file" do
+  setup do
+    open(path_to("history"), 'w') do |io|
+      io.puts((1..13).to_a)
+    end
+
+    Coolline::History.new(path_to("history"), 15)
+  end
+
+  asserts(:size).equals 13
+  asserts(:max_size).equals 15
+
+  1.upto(13) do |n|
+    asserts(:[], n - 1).equals n.to_s
+  end
+
+  asserts("search for 3") { topic.search(/3/).to_a }.equals [["13",12], ["3",2]]
+  asserts("search for 3 before last line") {
+    topic.search(/3/, -2).to_a
+  }.equals [["3",2]]
+
+  teardown do
+    File.delete path_to("history")
+  end
+end
+
+context "an history from a huge existing file" do
+  setup do
+    open(path_to("history"), 'w') do |io|
+      io.puts((1..20).to_a)
+    end
+
+    Coolline::History.new(path_to("history"), 15)
+  end
+
+  asserts(:size).equals 15
+  asserts(:max_size).equals 15
+
+  6.upto(20) do |n|
+    asserts(:[], n - 6).equals n.to_s
+  end
+
+  teardown do
+    File.delete path_to("history")
+  end
+end

test/run_all.rb

@@ -0,0 +1,5 @@
+require File.expand_path("helpers.rb", File.dirname(__FILE__))
+
+Dir.glob(File.join(File.dirname(__FILE__), "**/*_test.rb")) do |file|
+  load file
+end