[test] cope over RSA test from MRI's suite

as a guard against regression

Author: kares

src/test/ruby/rsa/test_rsa.rb

@@ -189,6 +189,57 @@ def test_read_private_key_with_password
     assert key.is_a?(OpenSSL::PKey::RSA)
   end
 
+  def test_RSAPrivateKey
+    rsa1024 = Fixtures.pkey("rsa1024")
+    assert_not_equal nil, rsa1024.dmp1
+    assert_not_equal nil, rsa1024.dmq1
+    assert_not_equal nil, rsa1024.iqmp
+
+    asn1 = OpenSSL::ASN1::Sequence([
+                                     OpenSSL::ASN1::Integer(0),
+                                     OpenSSL::ASN1::Integer(rsa1024.n),
+                                     OpenSSL::ASN1::Integer(rsa1024.e),
+                                     OpenSSL::ASN1::Integer(rsa1024.d),
+                                     OpenSSL::ASN1::Integer(rsa1024.p),
+                                     OpenSSL::ASN1::Integer(rsa1024.q),
+                                     OpenSSL::ASN1::Integer(rsa1024.dmp1), # nil???
+                                     OpenSSL::ASN1::Integer(rsa1024.dmq1),
+                                     OpenSSL::ASN1::Integer(rsa1024.iqmp)
+                                   ])
+    key = OpenSSL::PKey::RSA.new(asn1.to_der)
+    assert_predicate key, :private?
+    assert_same_rsa rsa1024, key
+
+    pem = <<~EOF
+    -----BEGIN RSA PRIVATE KEY-----
+    MIICXgIBAAKBgQDLwsSw1ECnPtT+PkOgHhcGA71nwC2/nL85VBGnRqDxOqjVh7Cx
+    aKPERYHsk4BPCkE3brtThPWc9kjHEQQ7uf9Y1rbCz0layNqHyywQEVLFmp1cpIt/
+    Q3geLv8ZD9pihowKJDyMDiN6ArYUmZczvW4976MU3+l54E6lF/JfFEU5hwIDAQAB
+    AoGBAKSl/MQarye1yOysqX6P8fDFQt68VvtXkNmlSiKOGuzyho0M+UVSFcs6k1L0
+    maDE25AMZUiGzuWHyaU55d7RXDgeskDMakD1v6ZejYtxJkSXbETOTLDwUWTn618T
+    gnb17tU1jktUtU67xK/08i/XodlgnQhs6VoHTuCh3Hu77O6RAkEA7+gxqBuZR572
+    74/akiW/SuXm0SXPEviyO1MuSRwtI87B02D0qgV8D1UHRm4AhMnJ8MCs1809kMQE
+    JiQUCrp9mQJBANlt2ngBO14us6NnhuAseFDTBzCHXwUUu1YKHpMMmxpnGqaldGgX
+    sOZB3lgJsT9VlGf3YGYdkLTNVbogQKlKpB8CQQDiSwkb4vyQfDe8/NpU5Not0fII
+    8jsDUCb+opWUTMmfbxWRR3FBNu8wnym/m19N4fFj8LqYzHX4KY0oVPu6qvJxAkEA
+    wa5snNekFcqONLIE4G5cosrIrb74sqL8GbGb+KuTAprzj5z1K8Bm0UW9lTjVDjDi
+    qRYgZfZSL+x1P/54+xTFSwJAY1FxA/N3QPCXCjPh5YqFxAMQs2VVYTfg+t0MEcJD
+    dPMQD5JX6g5HKnHFg2mZtoXQrWmJSn7p8GJK8yNTopEErA==
+    -----END RSA PRIVATE KEY-----
+    EOF
+    key = OpenSSL::PKey::RSA.new(pem)
+    assert_same_rsa rsa1024, key
+
+    assert_equal asn1.to_der, rsa1024.to_der
+    assert_equal pem, rsa1024.export
+
+    # Unknown PEM prepended
+    cert = issue_cert(OpenSSL::X509::Name.new([["CN", "nobody"]]), rsa1024, 1, [], nil, nil)
+    str = cert.to_text + cert.to_pem + rsa1024.to_pem
+    key = OpenSSL::PKey::RSA.new(str)
+    assert_same_rsa rsa1024, key
+  end
+
   def test_RSAPrivateKey_encrypted
     rsa1024 = Fixtures.pkey("rsa1024")
     # key = abcdef