test for #5380

test_5380.patch

diff --git a/test/ruby/envutil.rb b/test/ruby/envutil.rb
index de9055f..4a8451a 100644
--- a/test/ruby/envutil.rb
+++ b/test/ruby/envutil.rb
@@ -122,7 +122,13 @@ module Test
     module Assertions
       public
       def assert_normal_exit(testsrc, message = '', opt = {})
-        out, _, status = EnvUtil.invoke_ruby(%W'-W0', testsrc, true, :merge_to_stdout, opt)
+        if opt.include?(:child_env)
+          opt = opt.dup
+          child_env = [opt.delete(:child_env)] || []
+        else
+          child_env = []
+        end
+        out, _, status = EnvUtil.invoke_ruby(child_env + %W'-W0', testsrc, true, :merge_to_stdout, opt)
         pid = status.pid
         faildesc = proc do
           signo = status.termsig
diff --git a/test/ruby/test_gc.rb b/test/ruby/test_gc.rb
index 32b6e9f..b294c54 100644
--- a/test/ruby/test_gc.rb
+++ b/test/ruby/test_gc.rb
@@ -1,5 +1,7 @@
 require 'test/unit'
 
+require_relative "envutil"
+
 class TestGc < Test::Unit::TestCase
   class S
     def initialize(a)
@@ -78,4 +80,12 @@ class TestGc < Test::Unit::TestCase
   ensure
     GC.stress = prev_stress
   end
+
+  def test_gc_parameter
+    env = {
+      "RUBY_GC_MALLOC_LIMIT" => "60000000",
+      "RUBY_HEAP_MIN_SLOTS" => "100000"
+    }
+    assert_normal_exit("1", "[ruby-core:39777]", :child_env => env)
+  end
 end