Manage Requirements using ComparableSet

ComparableSet only allows a single object of a given class,
choosing the object with the greatest value. This was mainly created
for Requirements, so that, e.g., two X11Dependencies of differing
strictness don't both end up in the same requirement set.

Fixes #15240.

1 files changed, 40 insertions, 0 deletions

diff --git a/Library/Homebrew/test/test_comparableset.rb b/Library/Homebrew/test/test_comparableset.rb
new file mode 100644
index 000000000..d39ad51d6
--- /dev/null
+++ b/Library/Homebrew/test/test_comparableset.rb
@@ -0,0 +1,40 @@
+require 'testing_env'
+require 'extend/set'
+
+class ComparableSetTests < Test::Unit::TestCase
+  def setup
+    @set = ComparableSet.new
+  end
+
+  def test_merging_multiple_dependencies
+    @set << X11Dependency.new
+    @set << X11Dependency.new
+    assert_equal @set.count, 1
+    @set << Requirement.new
+    assert_equal @set.count, 2
+  end
+
+  def test_comparison_prefers_larger
+    @set << X11Dependency.new
+    @set << X11Dependency.new('2.6')
+    assert_equal @set.count, 1
+    assert_equal @set.to_a, [X11Dependency.new('2.6')]
+  end
+
+  def test_comparison_does_not_merge_smaller
+    @set << X11Dependency.new('2.6')
+    @set << X11Dependency.new
+    assert_equal @set.count, 1
+    assert_equal @set.to_a, [X11Dependency.new('2.6')]
+  end
+
+  def test_merging_sets
+    @set << X11Dependency.new
+    @set << Requirement.new
+    reqs = Set.new [X11Dependency.new('2.6'), Requirement.new]
+    @set.merge reqs
+
+    assert_equal @set.count, 2
+    assert_equal @set.find {|r| r.is_a? X11Dependency}, X11Dependency.new('2.6')
+  end
+end