diff --git a/src/crypto/x509/x509_test.cc b/src/crypto/x509/x509_test.cc
index 9ed1b52..bf0b29a 100644
--- a/src/crypto/x509/x509_test.cc
+++ b/src/crypto/x509/x509_test.cc
@@ -1549,3 +1549,125 @@
   EXPECT_EQ(ERR_LIB_X509, ERR_GET_LIB(err));
   EXPECT_EQ(X509_R_SIGNATURE_ALGORITHM_MISMATCH, ERR_GET_REASON(err));
 }
+
+TEST(X509Test, PEMX509Info) {
+  std::string cert = kRootCAPEM;
+  auto cert_obj = CertFromPEM(kRootCAPEM);
+  ASSERT_TRUE(cert_obj);
+
+  std::string rsa = kRSAKey;
+  auto rsa_obj = PrivateKeyFromPEM(kRSAKey);
+  ASSERT_TRUE(rsa_obj);
+
+  std::string crl = kBasicCRL;
+  auto crl_obj = CRLFromPEM(kBasicCRL);
+  ASSERT_TRUE(crl_obj);
+
+  std::string unknown =
+      "-----BEGIN UNKNOWN-----\n"
+      "AAAA\n"
+      "-----END UNKNOWN-----\n";
+
+  std::string invalid =
+      "-----BEGIN CERTIFICATE-----\n"
+      "AAAA\n"
+      "-----END CERTIFICATE-----\n";
+
+  // Each X509_INFO contains at most one certificate, CRL, etc. The format
+  // creates a new X509_INFO when a repeated type is seen.
+  std::string pem =
+      // The first few entries have one of everything in different orders.
+      cert + rsa + crl +
+      rsa + crl + cert +
+      // Unknown types are ignored.
+      crl + unknown + cert + rsa +
+      // Seeing a new certificate starts a new entry, so now we have a bunch of
+      // certificate-only entries.
+      cert + cert + cert +
+      // The key folds into the certificate's entry.
+      cert + rsa +
+      // Doubled keys also start new entries.
+      rsa + rsa + rsa + rsa + crl +
+      // As do CRLs.
+      crl + crl;
+
+  const struct ExpectedInfo {
+    const X509 *cert;
+    const EVP_PKEY *key;
+    const X509_CRL *crl;
+  } kExpected[] = {
+    {cert_obj.get(), rsa_obj.get(), crl_obj.get()},
+    {cert_obj.get(), rsa_obj.get(), crl_obj.get()},
+    {cert_obj.get(), rsa_obj.get(), crl_obj.get()},
+    {cert_obj.get(), nullptr, nullptr},
+    {cert_obj.get(), nullptr, nullptr},
+    {cert_obj.get(), nullptr, nullptr},
+    {cert_obj.get(), rsa_obj.get(), nullptr},
+    {nullptr, rsa_obj.get(), nullptr},
+    {nullptr, rsa_obj.get(), nullptr},
+    {nullptr, rsa_obj.get(), nullptr},
+    {nullptr, rsa_obj.get(), crl_obj.get()},
+    {nullptr, nullptr, crl_obj.get()},
+    {nullptr, nullptr, crl_obj.get()},
+  };
+
+  auto check_info = [](const ExpectedInfo *expected, const X509_INFO *info) {
+    if (expected->cert != nullptr) {
+      EXPECT_EQ(0, X509_cmp(expected->cert, info->x509));
+    } else {
+      EXPECT_EQ(nullptr, info->x509);
+    }
+    if (expected->crl != nullptr) {
+      EXPECT_EQ(0, X509_CRL_cmp(expected->crl, info->crl));
+    } else {
+      EXPECT_EQ(nullptr, info->crl);
+    }
+    if (expected->key != nullptr) {
+      ASSERT_NE(nullptr, info->x_pkey);
+      // EVP_PKEY_cmp returns one if the keys are equal.
+      EXPECT_EQ(1, EVP_PKEY_cmp(expected->key, info->x_pkey->dec_pkey));
+    } else {
+      EXPECT_EQ(nullptr, info->x_pkey);
+    }
+  };
+
+  bssl::UniquePtr<BIO> bio(BIO_new_mem_buf(pem.data(), pem.size()));
+  ASSERT_TRUE(bio);
+  bssl::UniquePtr<STACK_OF(X509_INFO)> infos(
+      PEM_X509_INFO_read_bio(bio.get(), nullptr, nullptr, nullptr));
+  ASSERT_TRUE(infos);
+  ASSERT_EQ(OPENSSL_ARRAY_SIZE(kExpected), sk_X509_INFO_num(infos.get()));
+  for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kExpected); i++) {
+    SCOPED_TRACE(i);
+    check_info(&kExpected[i], sk_X509_INFO_value(infos.get(), i));
+  }
+
+  // Passing an existing stack appends to it.
+  bio.reset(BIO_new_mem_buf(pem.data(), pem.size()));
+  ASSERT_TRUE(bio);
+  ASSERT_EQ(infos.get(),
+            PEM_X509_INFO_read_bio(bio.get(), infos.get(), nullptr, nullptr));
+  ASSERT_EQ(2 * OPENSSL_ARRAY_SIZE(kExpected), sk_X509_INFO_num(infos.get()));
+  for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kExpected); i++) {
+    SCOPED_TRACE(i);
+    check_info(&kExpected[i], sk_X509_INFO_value(infos.get(), i));
+    check_info(
+        &kExpected[i],
+        sk_X509_INFO_value(infos.get(), i + OPENSSL_ARRAY_SIZE(kExpected)));
+  }
+
+  // Gracefully handle errors in both the append and fresh cases.
+  std::string bad_pem = cert + cert + invalid;
+
+  bio.reset(BIO_new_mem_buf(bad_pem.data(), bad_pem.size()));
+  ASSERT_TRUE(bio);
+  bssl::UniquePtr<STACK_OF(X509_INFO)> infos2(
+      PEM_X509_INFO_read_bio(bio.get(), nullptr, nullptr, nullptr));
+  EXPECT_FALSE(infos2);
+
+  bio.reset(BIO_new_mem_buf(bad_pem.data(), bad_pem.size()));
+  ASSERT_TRUE(bio);
+  EXPECT_FALSE(
+      PEM_X509_INFO_read_bio(bio.get(), infos.get(), nullptr, nullptr));
+  EXPECT_EQ(2 * OPENSSL_ARRAY_SIZE(kExpected), sk_X509_INFO_num(infos.get()));
+}