Add method to filter a page's entries by time, resolves #9

lib/har/page.rb

@@ -11,5 +11,13 @@ def initialize(input, entries)
     # a little sugar
     alias_method :timings, :page_timings
 
+    # Filter entries that *finished* before the specified time
+    def entries_before(time)
+      raise TypeError, "expected Time" unless time.is_a?(Time)
+      entries.select do |entry|
+        return false unless entry.time
+        entry.started_date_time + entry.time / 1000.0 < time
+      end
+    end
   end
 end

spec/har/page_spec.rb

@@ -18,7 +18,20 @@ module HAR
       it "has a PageTimings instance" do
         page.timings.should be_kind_of(PageTimings)
       end
-    end
 
+      describe "#entries_before" do
+        it "requires a DateTime" do
+          expect { page.entries_before("a string") }.to raise_error(TypeError)
+        end
+
+        it "filters entries that responded before the specified time" do
+          time = page.started_date_time + 0.250
+          entries = page.entries_before(time)
+          entries.each do |entry|
+            (entry.started_date_time + entry.time / 1000.to_f).should < time
+          end
+        end
+      end
+    end
   end # Page
 end # HAR