2 files changed, 28 insertions, 0 deletions
diff --git a/activesupport/test/time_zone_test.rb b/activesupport/test/time_zone_test.rb
index 63ca22efb5..120afa61f2 100644
--- a/activesupport/test/time_zone_test.rb
+++ b/activesupport/test/time_zone_test.rb
@@ -725,6 +725,21 @@ class TimeZoneTest < ActiveSupport::TestCase
     assert_not_includes all_zones, galapagos
   end
 
+  def test_all_not_raises_exception_with_mizzing_tzinfo_data
+    mappings = {
+      "Puerto Rico" => "America/Unknown",
+      "Pittsburgh"  => "America/New_York"
+    }
+
+    with_tz_mappings(mappings) do
+      assert_nil ActiveSupport::TimeZone["Puerto Rico"]
+      assert_nil ActiveSupport::TimeZone[-9]
+      assert_nothing_raised do
+        ActiveSupport::TimeZone.all
+      end
+    end
+  end
+
   def test_index
     assert_nil ActiveSupport::TimeZone["bogus"]
     assert_instance_of ActiveSupport::TimeZone, ActiveSupport::TimeZone["Central Time (US & Canada)"]
diff --git a/activesupport/test/time_zone_test_helpers.rb b/activesupport/test/time_zone_test_helpers.rb
index 051703a781..85ed727c9b 100644
--- a/activesupport/test/time_zone_test_helpers.rb
+++ b/activesupport/test/time_zone_test_helpers.rb
@@ -23,4 +23,17 @@ module TimeZoneTestHelpers
   ensure
     ActiveSupport.to_time_preserves_timezone = old_preserve_tz
   end
+
+  def with_tz_mappings(mappings)
+    old_mappings = ActiveSupport::TimeZone::MAPPING.dup
+    ActiveSupport::TimeZone.clear
+    ActiveSupport::TimeZone::MAPPING.clear
+    ActiveSupport::TimeZone::MAPPING.merge!(mappings)
+
+    yield
+  ensure
+    ActiveSupport::TimeZone.clear
+    ActiveSupport::TimeZone::MAPPING.clear
+    ActiveSupport::TimeZone::MAPPING.merge!(old_mappings)
+  end
 end