Warn developers when uninstalling a dependency

Suggested in #1084.

Made the existing warning output entirely to STDERR, because
previously the first line went to STDERR and subsequent ones went
to STDOUT.

2 files changed, 42 insertions, 3 deletions

diff --git a/Library/Homebrew/test/test_uninstall.rb b/Library/Homebrew/test/test_uninstall.rb
index a7859b7ad..c9b3e0be3 100644
--- a/Library/Homebrew/test/test_uninstall.rb
+++ b/Library/Homebrew/test/test_uninstall.rb
@@ -2,20 +2,55 @@ require "helper/integration_command_test_case"
 require "cmd/uninstall"
 
 class UninstallTests < Homebrew::TestCase
+  def setup
+    @dependency = formula("dependency") { url "f-1" }
+    @dependent = formula("dependent") do
+      url "f-1"
+      depends_on "dependency"
+    end
+
+    [@dependency, @dependent].each { |f| f.installed_prefix.mkpath }
+
+    tab = Tab.empty
+    tab.tabfile = @dependent.installed_prefix/Tab::FILENAME
+    tab.runtime_dependencies = [
+      { "full_name" => "dependency", "version" => "1" },
+    ]
+    tab.write
+
+    stub_formula_loader @dependency
+    stub_formula_loader @dependent
+  end
+
+  def teardown
+    Homebrew.failed = false
+    [@dependency, @dependent].each { |f| f.rack.rmtree }
+  end
+
+  def handle_unsatisfied_dependents
+    capture_stderr do
+      opts = { @dependency.rack => [Keg.new(@dependency.installed_prefix)] }
+      Homebrew.handle_unsatisfied_dependents(opts)
+    end
+  end
+
   def test_check_for_testball_f2s_when_developer
-    refute_predicate Homebrew, :should_check_for_dependents?
+    assert_match "Warning", handle_unsatisfied_dependents
+    refute_predicate Homebrew, :failed?
   end
 
   def test_check_for_dependents_when_not_developer
     run_as_not_developer do
-      assert_predicate Homebrew, :should_check_for_dependents?
+      assert_match "Error", handle_unsatisfied_dependents
+      assert_predicate Homebrew, :failed?
     end
   end
 
   def test_check_for_dependents_when_ignore_dependencies
     ARGV << "--ignore-dependencies"
     run_as_not_developer do
-      refute_predicate Homebrew, :should_check_for_dependents?
+      assert_empty handle_unsatisfied_dependents
+      refute_predicate Homebrew, :failed?
     end
   ensure
     ARGV.delete("--ignore-dependencies")
diff --git a/Library/Homebrew/test/test_utils.rb b/Library/Homebrew/test/test_utils.rb
index 11332e450..7c0b6f78a 100644
--- a/Library/Homebrew/test/test_utils.rb
+++ b/Library/Homebrew/test/test_utils.rb
@@ -174,6 +174,10 @@ class UtilTests < Homebrew::TestCase
     end
   end
 
+  def test_capture_stderr
+    assert_equal "test\n", capture_stderr { $stderr.puts "test" }
+  end
+
   def test_shell_profile
     ENV["SHELL"] = "/bin/sh"
     assert_equal "~/.bash_profile", Utils::Shell.shell_profile