diff --git a/Rakefile.rb b/Rakefile.rb
index ce21fd3..cf00be9 100644
--- a/Rakefile.rb
+++ b/Rakefile.rb
@@ -17,12 +17,16 @@ task :build_dist do
 end
 
 RSpec::Core::RakeTask.new(:spec, :example_string) do |task, args|
+  ENV["specs"] = "1"
   if args.example_string
     ENV["partial_specs"] = "1"
     task.rspec_opts = %W[-e "#{args.example_string}" -f documentation]
   end
 end
 task :spec => :build_dist
+task :spec do
+  ENV.delete("specs")
+end
 
 # dspec task is useful to test the distributable release script, but is not
 # useful for coverage information.
@@ -31,7 +35,7 @@ task :dspec, [:example_string] => :build_dist do |task, args|
   FileUtils.mkdir_p("test")
   FileUtils.cp("dist/rscons", "test/rscons.rb")
   ENV["dist_specs"] = "1"
-  Rake::Task["spec"].invoke(args.example_string)
+  Rake::Task["spec"].execute(args.example_string)
   ENV.delete("dist_specs")
   FileUtils.rm_f(Dir.glob(".rscons-*"))
 end
@@ -99,6 +103,7 @@ task :default => :spec
 task :all => [
   :build_dist,
   :spec,
+  :dspec,
   :yard,
   :user_guide,
 ]
diff --git a/spec/build_tests_spec.rb b/spec/build_tests_spec.rb
index 31e6b24..28a38af 100644
--- a/spec/build_tests_spec.rb
+++ b/spec/build_tests_spec.rb
@@ -118,21 +118,23 @@ describe Rscons do
     command_name = "#{command_prefix}#{@statics[:build_test_id]}"
     File.open("_simplecov_setup.rb", "w") do |fh|
       fh.puts <<EOF
-require "bundler"
-Bundler.setup
-require "simplecov"
-class MyFormatter
-  def format(*args)
+unless ENV["dist_specs"]
+  require "bundler"
+  Bundler.setup
+  require "simplecov"
+  class MyFormatter
+    def format(*args)
+    end
   end
-end
-SimpleCov.start do
-  root(#{@owd.inspect})
-  command_name(#{command_name.inspect})
-  filters.clear
-  add_filter do |src|
-    !(src.filename[SimpleCov.root])
+  SimpleCov.start do
+    root(#{@owd.inspect})
+    command_name(#{command_name.inspect})
+    filters.clear
+    add_filter do |src|
+      !(src.filename[SimpleCov.root])
+    end
+    formatter(MyFormatter)
   end
-  formatter(MyFormatter)
 end
 # force color off
 ENV["TERM"] = nil
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 2d844d9..2fc400c 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,25 +1,25 @@
-require "simplecov"
-
-SimpleCov.start do
-  add_filter "/spec/"
-  add_filter "/.bundle/"
-  if ENV["partial_specs"]
-    command_name "RSpec-partial"
-  else
-    command_name "RSpec"
-  end
-  if ENV["dist_specs"]
-    add_filter "/bin/"
-    add_filter "/lib/"
-  else
-    add_filter "test/rscons.rb"
-  end
-  project_name "Rscons"
-  merge_timeout 3600
-end
-
 if ENV["dist_specs"]
   require_relative "../test/rscons"
 else
+  require "simplecov"
+
+  SimpleCov.start do
+    add_filter "/spec/"
+    add_filter "/.bundle/"
+    if ENV["partial_specs"]
+      command_name "RSpec-partial"
+    else
+      command_name "RSpec"
+    end
+    if ENV["dist_specs"]
+      add_filter "/bin/"
+      add_filter "/lib/"
+    else
+      add_filter "test/rscons.rb"
+    end
+    project_name "Rscons"
+    merge_timeout 3600
+  end
+
   require "rscons"
 end