python: tweak script linking in virtualenv (#613)

* python: tweak script linking in virtualenv

Instead of making the formula author use a slightly awkward block like

  venv.link_scripts(bin) { venv.pip_install buildpath }

avoid exposing this implementation detail and offer the more familiar:

  venv.pip_install buildpath, :link_scripts => bin

* Add non-block form and use instead of recursion

* Update 'pip_install' documentation

* Remove obsolete 'link_scripts'

* Add test for 'pip_install' with linking scripts

Also drop no longer relevant (and broken) `link_scripts` test, that
served as a template for the new test.

* Restore compatibility with Ruby 1.8.7

* Replace option hash with 'pip_install_and_link'

* Avoid confusing 'Object#tap' and fix silly bug

* Avoid side effects in mock object parameter check

* Simplify argument check (no need for a block)

1 files changed, 11 insertions, 11 deletions

diff --git a/Library/Homebrew/language/python.rb b/Library/Homebrew/language/python.rb
index 4249a911c..68e6f86ca 100644
--- a/Library/Homebrew/language/python.rb
+++ b/Library/Homebrew/language/python.rb
@@ -145,7 +145,7 @@ module Language
       def virtualenv_install_with_resources
         venv = virtualenv_create(libexec)
         venv.pip_install resources
-        venv.link_scripts(bin) { venv.pip_install buildpath }
+        venv.pip_install_and_link buildpath
         venv
       end
 
@@ -218,18 +218,18 @@ module Language
           end
         end
 
-        # Compares the venv bin directory before and after executing a block,
-        # and symlinks any new scripts into `destination`.
-        # Use like: venv.link_scripts(bin) { venv.pip_install my_package }
-        # @param destination [Pathname, String] Destination into which new
-        #   scripts should be linked.
-        # @return [void]
-        def link_scripts(destination)
+        # Installs packages represented by `targets` into the virtualenv, but
+        #   unlike {#pip_install} also links new scripts to {Formula#bin}.
+        # @param (see #pip_install)
+        # @return (see #pip_install)
+        def pip_install_and_link(targets)
           bin_before = Dir[@venv_root/"bin/*"].to_set
-          yield
+
+          pip_install(targets)
+
           bin_after = Dir[@venv_root/"bin/*"].to_set
-          destination = Pathname.new(destination)
-          destination.install_symlink((bin_after - bin_before).to_a)
+          bin_to_link = (bin_after - bin_before).to_a
+          @formula.bin.install_symlink(bin_to_link)
         end
 
         private