[test] do not redefine existing test methods (due some MRI tests cp-d)

Author: kares

src/test/ruby/test_bn.rb

@@ -50,6 +50,11 @@ def test_to_bn
 
     bn = OpenSSL::BN.new('1234567890123456789012345678901234567890')
     assert_equal bn, 1234567890123456789012345678901234567890.to_bn
+
+    e1 = OpenSSL::BN.new(999.to_s(16), 16)
+    e2 = OpenSSL::BN.new((2**107-1).to_s(16), 16)
+    assert_equal(e1, 999.to_bn)
+    assert_equal(e2, (2**107-1).to_bn)
   end
 
   def test_comparison
@@ -103,13 +108,6 @@ def test_new_integer
     assert_equal((-(2 ** 107 - 1)).to_bn, OpenSSL::BN.new(-(2 ** 107 - 1)))
   end
 
-  def test_to_bn
-    e1 = OpenSSL::BN.new(999.to_s(16), 16)
-    e2 = OpenSSL::BN.new((2**107-1).to_s(16), 16)
-    assert_equal(e1, 999.to_bn)
-    assert_equal(e2, (2**107-1).to_bn)
-  end
-
   def test_prime_p
     assert_equal(true, OpenSSL::BN.new((2 ** 107 - 1).to_s(16), 16).prime?)
     assert_equal(true, OpenSSL::BN.new((2 ** 127 - 1).to_s(16), 16).prime?(1))