Run specs in spec directory (if exists) by default

Closes #14
Closes #12

lib/rspec/core/configuration_options.rb

@@ -23,6 +23,7 @@ def apply_to(config)
 
       def parse_command_line_options
         @options = Parser.parse!(@args)
+        @args << 'spec' if @args.empty? and FileTest.directory? 'spec'
         @options[:files_or_directories_to_run] = @args
         @options
       end

lib/rspec/core/shared_example_group.rb

@@ -9,11 +9,17 @@ def share_examples_for(name, &block)
 
       def share_as(name, &block)
         if Object.const_defined?(name)
-          raise NameError, "The first argument (#{name}) to share_as must be a legal name for a constant not already in use."
+          mod = Object.const_get(name)
+          raise_name_error unless mod.created_from_caller(caller)
         end
 
         mod = Module.new do
           @shared_block = block
+          @caller_line = caller.last
+
+          def self.created_from_caller(other_caller)
+            @caller_line == other_caller.last
+          end
 
           def self.included(kls)
             kls.module_eval(&@shared_block)
@@ -28,6 +34,10 @@ def self.included(kls)
 
     private
 
+      def raise_name_error
+        raise NameError, "The first argument (#{name}) to share_as must be a legal name for a constant not already in use."
+      end
+
       def ensure_shared_example_group_name_not_taken(name)
         if Rspec::Core.world.shared_example_groups.has_key?(name)
           raise ArgumentError.new("Shared example group '#{name}' already exists")

spec/rspec/core/configuration_options_spec.rb

@@ -77,6 +77,21 @@ def options_from_args(*args)
       options_from_args("dir", "spec/file1_spec.rb", "spec/file2_spec.rb").should include(:files_or_directories_to_run => ["dir", "spec/file1_spec.rb", "spec/file2_spec.rb"])
     end
 
+    it "assumes a 'spec' directory if it exists" do
+      FileTest.stub(:directory?).with("spec").and_return true
+      options_from_args().should include(:files_or_directories_to_run => ["spec"])
+    end
+
+    it "provides no files or directories if spec directory does not exist" do
+      FileTest.stub(:directory?).with("spec").and_return false
+      options_from_args().should include(:files_or_directories_to_run => [])
+    end
+
+    it "parses dir and files from 'spec/file1_spec.rb, spec/file2_spec.rb'" do
+      options_from_args("dir", "spec/file1_spec.rb", "spec/file2_spec.rb").should include(:files_or_directories_to_run => ["dir", "spec/file1_spec.rb", "spec/file2_spec.rb"])
+
+    end
+
   end
 
   describe "--backtrace (-b)" do