Fix the 'export PATH' message in `link` for a keg-only formula

Commit 4cae6a724e6d684eb157dd6d7328755694f228b2 introduced the message,
but it printed the wrong path, e.g. for `brew link sqlite`:

```
If you need to have this software first in your PATH instead consider running:
  echo 'export PATH="/usr/local/opt/sqlite:$PATH"' >> ~/.zshrc/bin
```

where `/bin` is appended at the end, but should be inserted before
`:$PATH`: `echo 'export PATH="/usr/local/opt/sqlite/bin:$PATH"' >> ~/.zshrc`.
This patch fixes that and updates a test to verify it.

2 files changed, 6 insertions, 4 deletions

diff --git a/Library/Homebrew/cmd/link.rb b/Library/Homebrew/cmd/link.rb
index 293f09eef..a1d1397da 100644
--- a/Library/Homebrew/cmd/link.rb
+++ b/Library/Homebrew/cmd/link.rb
@@ -86,8 +86,8 @@ module Homebrew
 
     opt = HOMEBREW_PREFIX/"opt/#{keg.name}"
     puts "\nIf you need to have this software first in your PATH instead consider running:"
-    puts "  #{Utils::Shell.prepend_path_in_shell_profile(opt)}/bin"  if bin.directory?
-    puts "  #{Utils::Shell.prepend_path_in_shell_profile(opt)}/sbin" if sbin.directory?
+    puts "  #{Utils::Shell.prepend_path_in_shell_profile(opt/"bin")}"  if bin.directory?
+    puts "  #{Utils::Shell.prepend_path_in_shell_profile(opt/"sbin")}" if sbin.directory?
   end
 
   def keg_only?(rack)
diff --git a/Library/Homebrew/test/cmd/link_spec.rb b/Library/Homebrew/test/cmd/link_spec.rb
index 7b85c96dc..59ab86cc4 100644
--- a/Library/Homebrew/test/cmd/link_spec.rb
+++ b/Library/Homebrew/test/cmd/link_spec.rb
@@ -48,9 +48,11 @@ describe "brew link", :integration_test do
       expect { brew "install", "testball1" }.to be_a_success
     end
 
-    expect { brew "link", "testball1" }
+    expect { brew "link", "testball1", "SHELL" => "/bin/zsh" }
       .to output(/testball1 is keg-only/).to_stderr
-      .and output(/Note that doing so can interfere with building software\./).to_stdout
+      .and output(a_string_matching(/Note that doing so can interfere with building software\./)
+        .and(matching("If you need to have this software first in your PATH instead consider running:")
+        .and(including("echo 'export PATH=\"#{HOMEBREW_PREFIX}/opt/testball1/bin:$PATH\"' >> ~/.zshrc")))).to_stdout
       .and be_a_success
   end
 end