Infer path to be added for requirements that search PATH

When a requirement is specified like:

  satisfy { which "foo" }

There is no reason that we should inject all of ENV.userpaths! into the
build environment. Instead, infer the directory to be added to PATH from
the Pathname that is returned.

This is another step towards condensing the "which program" requirements
down into a one-liner DSL element.

1 files changed, 13 insertions, 0 deletions

diff --git a/Library/Homebrew/test/test_requirement.rb b/Library/Homebrew/test/test_requirement.rb
index 0319e9e25..e8803ed92 100644
--- a/Library/Homebrew/test/test_requirement.rb
+++ b/Library/Homebrew/test/test_requirement.rb
@@ -74,4 +74,17 @@ class RequirementTests < Test::Unit::TestCase
 
     assert req.satisfied?
   end
+
+  def test_infers_path_from_satisfy_result
+    which_path = Pathname.new("/foo/bar/baz")
+    req = Class.new(Requirement) do
+      satisfy { which_path }
+    end.new
+
+    ENV.expects(:with_build_environment).yields.returns(which_path)
+    ENV.expects(:userpaths!)
+    ENV.expects(:append).with("PATH", which_path.parent, ":")
+
+    req.modify_build_environment
+  end
 end