openssl: clear OpenSSL error queue before return to Rubytopic/openssl-clear-error-queue

* ext/openssl/ossl_x509cert.c (ossl_x509_verify): X509_verify()
  family may put errors on 0 return (0 means verification failure).
  Clear OpenSSL error queue before return to Ruby. Since the queue is
  thread global, remaining errors in the queue can cause an unexpected
  error in the next OpenSSL operation.  [ruby-core:48284] [Bug #7215]

* ext/openssl/ossl_x509crl.c (ossl_x509crl_verify): ditto.

* ext/openssl/ossl_x509req.c (ossl_x509req_verify): ditto.

* ext/openssl/ossl_x509store.c (ossl_x509stctx_verify): ditto.

* ext/openssl/ossl_pkey_dh.c (dh_generate): clear the OpenSSL error
  queue before re-raising exception.

* ext/openssl/ossl_pkey_dsa.c (dsa_generate): ditto.

* ext/openssl/ossl_pkey_rsa.c (rsa_generate): ditto.

* ext/openssl/ossl_ssl.c (ossl_start_ssl): ditto.

* test/openssl: check that OpenSSL.errors is empty every time after
  running a test case.

27 files changed, 43 insertions, 77 deletions

diff --git a/test/openssl/test_asn1.rb b/test/openssl/test_asn1.rb
index fd2118d808..9db9ec510b 100644
--- a/test/openssl/test_asn1.rb
+++ b/test/openssl/test_asn1.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: false
 require_relative 'utils'
 
-class  OpenSSL::TestASN1 < Test::Unit::TestCase
+class  OpenSSL::TestASN1 < OpenSSL::TestCase
   def test_decode
     subj = OpenSSL::X509::Name.parse("/DC=org/DC=ruby-lang/CN=TestCA")
     key = OpenSSL::TestUtils::TEST_KEY_RSA1024
diff --git a/test/openssl/test_bn.rb b/test/openssl/test_bn.rb
index 415bd74c79..37ba5e5595 100644
--- a/test/openssl/test_bn.rb
+++ b/test/openssl/test_bn.rb
@@ -3,7 +3,7 @@ require_relative 'utils'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestBN < Test::Unit::TestCase
+class OpenSSL::TestBN < OpenSSL::TestCase
   def test_new_str
     e1 = OpenSSL::BN.new(999.to_s(16), 16) # OpenSSL::BN.new(str, 16) must be most stable
     e2 = OpenSSL::BN.new((2**107-1).to_s(16), 16)
diff --git a/test/openssl/test_buffering.rb b/test/openssl/test_buffering.rb
index 1f552c935b..1f42cd3c31 100644
--- a/test/openssl/test_buffering.rb
+++ b/test/openssl/test_buffering.rb
@@ -2,7 +2,7 @@
 require_relative 'utils'
 require 'stringio'
 
-class OpenSSL::TestBuffering < Test::Unit::TestCase
+class OpenSSL::TestBuffering < OpenSSL::TestCase
 
   class IO
     include OpenSSL::Buffering
diff --git a/test/openssl/test_cipher.rb b/test/openssl/test_cipher.rb
index 32f0d118f4..dab64aa5a1 100644
--- a/test/openssl/test_cipher.rb
+++ b/test/openssl/test_cipher.rb
@@ -3,7 +3,7 @@ require_relative 'utils'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestCipher < Test::Unit::TestCase
+class OpenSSL::TestCipher < OpenSSL::TestCase
 
   class << self
 
@@ -34,6 +34,7 @@ class OpenSSL::TestCipher < Test::Unit::TestCase
   end
 
   def teardown
+    super
     @c1 = @c2 = nil
   end
 
diff --git a/test/openssl/test_config.rb b/test/openssl/test_config.rb
index 1a5dfe62e8..bedd1d047c 100644
--- a/test/openssl/test_config.rb
+++ b/test/openssl/test_config.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: false
 require_relative 'utils'
 
-class OpenSSL::TestConfig < Test::Unit::TestCase
+class OpenSSL::TestConfig < OpenSSL::TestCase
   def setup
     file = Tempfile.open("openssl.cnf")
     file << <<__EOD__
@@ -18,6 +18,7 @@ __EOD__
   end
 
   def teardown
+    super
     @tmpfile.close!
   end
 
diff --git a/test/openssl/test_digest.rb b/test/openssl/test_digest.rb
index 8b724a03a9..ba3e974bc6 100644
--- a/test/openssl/test_digest.rb
+++ b/test/openssl/test_digest.rb
@@ -3,7 +3,7 @@ require_relative 'utils'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestDigest < Test::Unit::TestCase
+class OpenSSL::TestDigest < OpenSSL::TestCase
   def setup
     @d1 = OpenSSL::Digest.new("MD5")
     @d2 = OpenSSL::Digest::MD5.new
@@ -12,6 +12,7 @@ class OpenSSL::TestDigest < Test::Unit::TestCase
   end
 
   def teardown
+    super
     @d1 = @d2 = @md = nil
   end
 
diff --git a/test/openssl/test_engine.rb b/test/openssl/test_engine.rb
index 3521de6396..9a0da34070 100644
--- a/test/openssl/test_engine.rb
+++ b/test/openssl/test_engine.rb
@@ -1,9 +1,10 @@
 # frozen_string_literal: false
 require_relative 'utils'
 
-class OpenSSL::TestEngine < Test::Unit::TestCase
+class OpenSSL::TestEngine < OpenSSL::TestCase
 
   def teardown
+    super
     OpenSSL::Engine.cleanup # [ruby-core:40669]
     assert_equal(0, OpenSSL::Engine.engines.size)
   end
diff --git a/test/openssl/test_fips.rb b/test/openssl/test_fips.rb
index 33769c9388..534dade02b 100644
--- a/test/openssl/test_fips.rb
+++ b/test/openssl/test_fips.rb
@@ -3,7 +3,7 @@ require_relative 'utils'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestFIPS < Test::Unit::TestCase
+class OpenSSL::TestFIPS < OpenSSL::TestCase
 
   def test_fips_mode_is_reentrant
     OpenSSL.fips_mode = false
diff --git a/test/openssl/test_hmac.rb b/test/openssl/test_hmac.rb
index 135d26f02c..3c90a5de02 100644
--- a/test/openssl/test_hmac.rb
+++ b/test/openssl/test_hmac.rb
@@ -3,7 +3,7 @@
 
 require_relative 'utils'
 
-class OpenSSL::TestHMAC < Test::Unit::TestCase
+class OpenSSL::TestHMAC < OpenSSL::TestCase
   def setup
     @digest = OpenSSL::Digest::MD5
     @key = "KEY"
@@ -12,9 +12,6 @@ class OpenSSL::TestHMAC < Test::Unit::TestCase
     @h2 = OpenSSL::HMAC.new(@key, "MD5")
   end
 
-  def teardown
-  end
-
   def test_hmac
     @h1.update(@data)
     @h2.update(@data)
diff --git a/test/openssl/test_ns_spki.rb b/test/openssl/test_ns_spki.rb
index 4f6e6f59e7..4740c0b29e 100644
--- a/test/openssl/test_ns_spki.rb
+++ b/test/openssl/test_ns_spki.rb
@@ -3,7 +3,7 @@ require_relative 'utils'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestNSSPI < Test::Unit::TestCase
+class OpenSSL::TestNSSPI < OpenSSL::TestCase
   def setup
     # This request data is adopt from the specification of
     # "Netscape Extensions for User Key Generation".
diff --git a/test/openssl/test_ocsp.rb b/test/openssl/test_ocsp.rb
index 1a969fd767..d04b421615 100644
--- a/test/openssl/test_ocsp.rb
+++ b/test/openssl/test_ocsp.rb
@@ -3,7 +3,7 @@ require_relative "utils"
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestOCSP < Test::Unit::TestCase
+class OpenSSL::TestOCSP < OpenSSL::TestCase
   def setup
     ca_subj = OpenSSL::X509::Name.parse("/DC=org/DC=ruby-lang/CN=TestCA")
     ca_key = OpenSSL::TestUtils::TEST_KEY_RSA1024
diff --git a/test/openssl/test_pair.rb b/test/openssl/test_pair.rb
index 06c34442b7..38b33a4622 100644
--- a/test/openssl/test_pair.rb
+++ b/test/openssl/test_pair.rb
@@ -517,36 +517,36 @@ module OpenSSL::TestPairM
   end
 end
 
-class OpenSSL::TestEOF1 < Test::Unit::TestCase
+class OpenSSL::TestEOF1 < OpenSSL::TestCase
   include TestEOF
   include OpenSSL::SSLPair
   include OpenSSL::TestEOF1M
 end
 
-class OpenSSL::TestEOF1LowlevelSocket < Test::Unit::TestCase
+class OpenSSL::TestEOF1LowlevelSocket < OpenSSL::TestCase
   include TestEOF
   include OpenSSL::SSLPairLowlevelSocket
   include OpenSSL::TestEOF1M
 end
 
-class OpenSSL::TestEOF2 < Test::Unit::TestCase
+class OpenSSL::TestEOF2 < OpenSSL::TestCase
   include TestEOF
   include OpenSSL::SSLPair
   include OpenSSL::TestEOF2M
 end
 
-class OpenSSL::TestEOF2LowlevelSocket < Test::Unit::TestCase
+class OpenSSL::TestEOF2LowlevelSocket < OpenSSL::TestCase
   include TestEOF
   include OpenSSL::SSLPairLowlevelSocket
   include OpenSSL::TestEOF2M
 end
 
-class OpenSSL::TestPair < Test::Unit::TestCase
+class OpenSSL::TestPair < OpenSSL::TestCase
   include OpenSSL::SSLPair
   include OpenSSL::TestPairM
 end
 
-class OpenSSL::TestPairLowlevelSocket < Test::Unit::TestCase
+class OpenSSL::TestPairLowlevelSocket < OpenSSL::TestCase
   include OpenSSL::SSLPairLowlevelSocket
   include OpenSSL::TestPairM
 end
diff --git a/test/openssl/test_pkcs12.rb b/test/openssl/test_pkcs12.rb
index ba07d76789..61fb447473 100644
--- a/test/openssl/test_pkcs12.rb
+++ b/test/openssl/test_pkcs12.rb
@@ -4,7 +4,7 @@ require_relative "utils"
 if defined?(OpenSSL::TestUtils)
 
 module OpenSSL
-  class TestPKCS12 < Test::Unit::TestCase
+  class TestPKCS12 < OpenSSL::TestCase
     include OpenSSL::TestUtils
 
     def setup
diff --git a/test/openssl/test_pkcs5.rb b/test/openssl/test_pkcs5.rb
index f38fd716b7..ad8132c263 100644
--- a/test/openssl/test_pkcs5.rb
+++ b/test/openssl/test_pkcs5.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: false
 require_relative 'utils'
 
-class OpenSSL::TestPKCS5 < Test::Unit::TestCase
+class OpenSSL::TestPKCS5 < OpenSSL::TestCase
 
   def test_pbkdf2_hmac_sha1_rfc6070_c_1_len_20
     p ="password"
diff --git a/test/openssl/test_pkcs7.rb b/test/openssl/test_pkcs7.rb
index ce99db50b1..dfe4c6ca82 100644
--- a/test/openssl/test_pkcs7.rb
+++ b/test/openssl/test_pkcs7.rb
@@ -3,7 +3,7 @@ require_relative 'utils'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestPKCS7 < Test::Unit::TestCase
+class OpenSSL::TestPKCS7 < OpenSSL::TestCase
   def setup
     @rsa1024 = OpenSSL::TestUtils::TEST_KEY_RSA1024
     @rsa2048 = OpenSSL::TestUtils::TEST_KEY_RSA2048
diff --git a/test/openssl/test_pkey_dh.rb b/test/openssl/test_pkey_dh.rb
index a0eca53c48..afd7a3187c 100644
--- a/test/openssl/test_pkey_dh.rb
+++ b/test/openssl/test_pkey_dh.rb
@@ -3,7 +3,7 @@ require_relative 'utils'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestPKeyDH < Test::Unit::TestCase
+class OpenSSL::TestPKeyDH < OpenSSL::TestCase
 
   NEW_KEYLEN = 256
 
diff --git a/test/openssl/test_pkey_dsa.rb b/test/openssl/test_pkey_dsa.rb
index eb3e4f1c65..2c0e1fc24f 100644
--- a/test/openssl/test_pkey_dsa.rb
+++ b/test/openssl/test_pkey_dsa.rb
@@ -4,7 +4,7 @@ require 'base64'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestPKeyDSA < Test::Unit::TestCase
+class OpenSSL::TestPKeyDSA < OpenSSL::TestCase
   def test_private
     key = OpenSSL::PKey::DSA.new(256)
     assert(key.private?)
@@ -20,7 +20,6 @@ class OpenSSL::TestPKeyDSA < Test::Unit::TestCase
     key = OpenSSL::PKey::DSA.new 256
     pem  = key.public_key.to_pem
     OpenSSL::PKey::DSA.new pem
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_new_break
@@ -84,7 +83,6 @@ end
     assert_equal(g, key.g)
     assert_equal(y, key.pub_key)
     assert_equal(nil, key.priv_key)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_DSAPublicKey_pem
@@ -109,7 +107,6 @@ fWLOqqkzFeRrYMDzUpl36XktY6Yq8EJYlW9pCMmBVNy/dQ==
     assert_equal(g, key.g)
     assert_equal(y, key.pub_key)
     assert_equal(nil, key.priv_key)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_DSA_PUBKEY_pem
@@ -135,7 +132,6 @@ YNMbNw==
     assert_equal(g, key.g)
     assert_equal(y, key.pub_key)
     assert_equal(nil, key.priv_key)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_export_format_is_DSA_PUBKEY_pem
@@ -165,7 +161,6 @@ YNMbNw==
     pub_key = OpenSSL::ASN1.decode(seq[1].value)
     assert_equal(OpenSSL::ASN1::INTEGER, pub_key.tag)
     assert_equal(key.pub_key, pub_key.value)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_private_key_der
@@ -174,7 +169,6 @@ YNMbNw==
     key2 = OpenSSL::PKey.read(der)
     assert(key2.private?)
     assert_equal(der, key2.to_der)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_private_key_pem
@@ -183,7 +177,6 @@ YNMbNw==
     key2 = OpenSSL::PKey.read(pem)
     assert(key2.private?)
     assert_equal(pem, key2.to_pem)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_public_key_der
@@ -192,7 +185,6 @@ YNMbNw==
     key2 = OpenSSL::PKey.read(der)
     assert(!key2.private?)
     assert_equal(der, key2.to_der)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_public_key_pem
@@ -201,7 +193,6 @@ YNMbNw==
     key2 = OpenSSL::PKey.read(pem)
     assert(!key2.private?)
     assert_equal(pem, key2.to_pem)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_private_key_pem_pw
@@ -216,7 +207,6 @@ YNMbNw==
     key2 = OpenSSL::PKey.read(pem, 'secret')
     assert(key2.private?)
     #omit pem equality check, will be different due to cipher iv
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_export_password_length
diff --git a/test/openssl/test_pkey_ec.rb b/test/openssl/test_pkey_ec.rb
index d3edcc47b4..c530ee06b0 100644
--- a/test/openssl/test_pkey_ec.rb
+++ b/test/openssl/test_pkey_ec.rb
@@ -3,7 +3,7 @@ require_relative 'utils'
 
 if defined?(OpenSSL::TestUtils) && defined?(OpenSSL::PKey::EC)
 
-class OpenSSL::TestEC < Test::Unit::TestCase
+class OpenSSL::TestEC < OpenSSL::TestCase
   def setup
     @data1 = 'foo'
     @data2 = 'bar' * 1000 # data too long for DSA sig
@@ -131,7 +131,6 @@ class OpenSSL::TestEC < Test::Unit::TestCase
     ec2 = OpenSSL::PKey.read(der)
     assert(ec2.private_key?)
     assert_equal(der, ec2.to_der)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_private_key_pem
@@ -140,7 +139,6 @@ class OpenSSL::TestEC < Test::Unit::TestCase
     ec2 = OpenSSL::PKey.read(pem)
     assert(ec2.private_key?)
     assert_equal(pem, ec2.to_pem)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_public_key_der
@@ -151,7 +149,6 @@ class OpenSSL::TestEC < Test::Unit::TestCase
     ec3 = OpenSSL::PKey.read(der)
     assert(!ec3.private_key?)
     assert_equal(der, ec3.to_der)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_public_key_pem
@@ -162,7 +159,6 @@ class OpenSSL::TestEC < Test::Unit::TestCase
     ec3 = OpenSSL::PKey.read(pem)
     assert(!ec3.private_key?)
     assert_equal(pem, ec3.to_pem)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_private_key_pem_pw
@@ -177,7 +173,6 @@ class OpenSSL::TestEC < Test::Unit::TestCase
     ec2 = OpenSSL::PKey.read(pem, 'secret')
     assert(ec2.private_key?)
     #omit pem equality check, will be different due to cipher iv
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_export_password_length
diff --git a/test/openssl/test_pkey_rsa.rb b/test/openssl/test_pkey_rsa.rb
index 165b1ec98e..54fce2f59e 100644
--- a/test/openssl/test_pkey_rsa.rb
+++ b/test/openssl/test_pkey_rsa.rb
@@ -4,7 +4,7 @@ require 'base64'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestPKeyRSA < Test::Unit::TestCase
+class OpenSSL::TestPKeyRSA < OpenSSL::TestCase
   def test_padding
     key = OpenSSL::PKey::RSA.new(512, 3)
 
@@ -180,7 +180,6 @@ AudJR1JobbIbDJrQu6AXnWh5k/YtAgMBAAE=
     assert_equal(nil, key.d)
     assert_equal(nil, key.p)
     assert_equal(nil, key.q)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_RSA_PUBKEY_pem
@@ -201,7 +200,6 @@ AwEAAQ==
     assert_equal(nil, key.d)
     assert_equal(nil, key.p)
     assert_equal(nil, key.q)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_export_format_is_RSA_PUBKEY
@@ -223,7 +221,6 @@ AwEAAQ==
     key = OpenSSL::PKey.read(der)
     assert(key.private?)
     assert_equal(der, key.to_der)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_private_key_pem
@@ -231,7 +228,6 @@ AwEAAQ==
     key = OpenSSL::PKey.read(pem)
     assert(key.private?)
     assert_equal(pem, key.to_pem)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_public_key_der
@@ -239,7 +235,6 @@ AwEAAQ==
     key = OpenSSL::PKey.read(der)
     assert(!key.private?)
     assert_equal(der, key.to_der)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_public_key_pem
@@ -247,7 +242,6 @@ AwEAAQ==
     key = OpenSSL::PKey.read(pem)
     assert(!key.private?)
     assert_equal(pem, key.to_pem)
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_private_key_pem_pw
@@ -261,7 +255,6 @@ AwEAAQ==
     key = OpenSSL::PKey.read(pem, 'secret')
     assert(key.private?)
     #omit pem equality check, will be different due to cipher iv
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_read_private_key_pem_pw_exception
@@ -272,7 +265,6 @@ AwEAAQ==
         raise RuntimeError
       end
     end
-    assert_equal([], OpenSSL.errors)
   end
 
   def test_export_password_length
@@ -306,7 +298,6 @@ AwEAAQ==
     assert_equal(key.n, pub_key.value[0].value)
     assert_equal(OpenSSL::ASN1::INTEGER, pub_key.value[1].tag)
     assert_equal(key.e, pub_key.value[1].value)
-    assert_equal([], OpenSSL.errors)
   end
 
 end
diff --git a/test/openssl/test_random.rb b/test/openssl/test_random.rb
index 8c69d5431c..defa09dd75 100644
--- a/test/openssl/test_random.rb
+++ b/test/openssl/test_random.rb
@@ -4,7 +4,7 @@ begin
 rescue LoadError
 end
 
-class OpenSSL::TestRandom < Test::Unit::TestCase
+class OpenSSL::TestRandom < OpenSSL::TestCase
   def test_random_bytes
     assert_equal("", OpenSSL::Random.random_bytes(0))
     assert_equal(12, OpenSSL::Random.random_bytes(12).bytesize)
diff --git a/test/openssl/test_x509cert.rb b/test/openssl/test_x509cert.rb
index 72cb9e6095..ae7a0f0855 100644
--- a/test/openssl/test_x509cert.rb
+++ b/test/openssl/test_x509cert.rb
@@ -3,7 +3,7 @@ require_relative "utils"
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestX509Certificate < Test::Unit::TestCase
+class OpenSSL::TestX509Certificate < OpenSSL::TestCase
   def setup
     @rsa1024 = OpenSSL::TestUtils::TEST_KEY_RSA1024
     @rsa2048 = OpenSSL::TestUtils::TEST_KEY_RSA2048
@@ -14,9 +14,6 @@ class OpenSSL::TestX509Certificate < Test::Unit::TestCase
     @ee2 = OpenSSL::X509::Name.parse("/DC=org/DC=ruby-lang/CN=EE2")
   end
 
-  def teardown
-  end
-
   def issue_cert(*args)
     OpenSSL::TestUtils.issue_cert(*args)
   end
diff --git a/test/openssl/test_x509crl.rb b/test/openssl/test_x509crl.rb
index 7994ddeaf9..fd66c97588 100644
--- a/test/openssl/test_x509crl.rb
+++ b/test/openssl/test_x509crl.rb
@@ -3,7 +3,7 @@ require_relative "utils"
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestX509CRL < Test::Unit::TestCase
+class OpenSSL::TestX509CRL < OpenSSL::TestCase
   def setup
     @rsa1024 = OpenSSL::TestUtils::TEST_KEY_RSA1024
     @rsa2048 = OpenSSL::TestUtils::TEST_KEY_RSA2048
@@ -14,9 +14,6 @@ class OpenSSL::TestX509CRL < Test::Unit::TestCase
     @ee2 = OpenSSL::X509::Name.parse("/DC=org/DC=ruby-lang/CN=EE2")
   end
 
-  def teardown
-  end
-
   def issue_crl(*args)
     OpenSSL::TestUtils.issue_crl(*args)
   end
diff --git a/test/openssl/test_x509ext.rb b/test/openssl/test_x509ext.rb
index e6d49bb679..99e2eda5b3 100644
--- a/test/openssl/test_x509ext.rb
+++ b/test/openssl/test_x509ext.rb
@@ -3,7 +3,7 @@ require_relative 'utils'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestX509Extension < Test::Unit::TestCase
+class OpenSSL::TestX509Extension < OpenSSL::TestCase
   def setup
     @basic_constraints_value = OpenSSL::ASN1::Sequence([
       OpenSSL::ASN1::Boolean(true),   # CA
@@ -16,9 +16,6 @@ class OpenSSL::TestX509Extension < Test::Unit::TestCase
     ])
   end
 
-  def teardown
-  end
-
   def test_new
     ext = OpenSSL::X509::Extension.new(@basic_constraints.to_der)
     assert_equal("basicConstraints", ext.oid)
diff --git a/test/openssl/test_x509name.rb b/test/openssl/test_x509name.rb
index 56e79879cf..d26174efdf 100644
--- a/test/openssl/test_x509name.rb
+++ b/test/openssl/test_x509name.rb
@@ -4,7 +4,7 @@ require_relative 'utils'
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestX509Name < Test::Unit::TestCase
+class OpenSSL::TestX509Name < OpenSSL::TestCase
   OpenSSL::ASN1::ObjectId.register(
     "1.2.840.113549.1.9.1", "emailAddress", "emailAddress")
   OpenSSL::ASN1::ObjectId.register(
@@ -15,9 +15,6 @@ class OpenSSL::TestX509Name < Test::Unit::TestCase
     @obj_type_tmpl.update(OpenSSL::X509::Name::OBJECT_TYPE_TEMPLATE)
   end
 
-  def teardown
-  end
-
   def test_s_new
     dn = [ ["C", "JP"], ["O", "example"], ["CN", "www.example.jp"] ]
     name = OpenSSL::X509::Name.new(dn)
diff --git a/test/openssl/test_x509req.rb b/test/openssl/test_x509req.rb
index f1bf18465f..7ceff5839b 100644
--- a/test/openssl/test_x509req.rb
+++ b/test/openssl/test_x509req.rb
@@ -3,7 +3,7 @@ require_relative "utils"
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestX509Request < Test::Unit::TestCase
+class OpenSSL::TestX509Request < OpenSSL::TestCase
   def setup
     @rsa1024 = OpenSSL::TestUtils::TEST_KEY_RSA1024
     @rsa2048 = OpenSSL::TestUtils::TEST_KEY_RSA2048
diff --git a/test/openssl/test_x509store.rb b/test/openssl/test_x509store.rb
index 9964cc8fc4..6a443a7cf1 100644
--- a/test/openssl/test_x509store.rb
+++ b/test/openssl/test_x509store.rb
@@ -3,7 +3,7 @@ require_relative "utils"
 
 if defined?(OpenSSL::TestUtils)
 
-class OpenSSL::TestX509Store < Test::Unit::TestCase
+class OpenSSL::TestX509Store < OpenSSL::TestCase
   def setup
     @rsa1024 = OpenSSL::TestUtils::TEST_KEY_RSA1024
     @rsa2048 = OpenSSL::TestUtils::TEST_KEY_RSA2048
@@ -15,9 +15,6 @@ class OpenSSL::TestX509Store < Test::Unit::TestCase
     @ee2 = OpenSSL::X509::Name.parse("/DC=org/DC=ruby-lang/CN=EE2")
   end
 
-  def teardown
-  end
-
   def test_nosegv_on_cleanup
     cert  = OpenSSL::X509::Certificate.new
     store = OpenSSL::X509::Store.new
diff --git a/test/openssl/utils.rb b/test/openssl/utils.rb
index 6909854cad..450250169b 100644
--- a/test/openssl/utils.rb
+++ b/test/openssl/utils.rb
@@ -181,7 +181,14 @@ AQjjxMXhwULlmuR/K+WwlaZPiLIBYalLAZQ7ZbOPeVkJ8ePao0eLAgEC
     end
   end
 
-  class OpenSSL::SSLTestCase < Test::Unit::TestCase
+  class OpenSSL::TestCase < Test::Unit::TestCase
+    def teardown
+      # OpenSSL error stack must be empty
+      assert_equal([], OpenSSL.errors)
+    end
+  end
+
+  class OpenSSL::SSLTestCase < OpenSSL::TestCase
     RUBY = EnvUtil.rubybin
     ITERATIONS = ($0 == __FILE__) ? 100 : 10
 
@@ -206,9 +213,6 @@ AQjjxMXhwULlmuR/K+WwlaZPiLIBYalLAZQ7ZbOPeVkJ8ePao0eLAgEC
       @server = nil
     end
 
-    def teardown
-    end
-
     def issue_cert(*arg)
       OpenSSL::TestUtils.issue_cert(*arg)
     end