diff --git a/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp b/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp
index 356a8745..52aa92d1 100644
--- a/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp
+++ b/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp
@@ -2624,6 +2624,42 @@ TEST_P(OEMCryptoSessionTestsDecryptTests, SingleLargeSubsample) {
   TestDecryptCENC(key, encryptionIv, encryptedData, unencryptedData);
 }
 
+TEST_P(OEMCryptoSessionTestsDecryptTests, PatternPlusOneBlock) {
+  // When the pattern length is 10 blocks, there is a discrepancy between the
+  // HLS and the CENC standards for samples of size 160*N+16, for N = 1, 2, 3 ...
+  // We require the CENC standard for OEMCrypto, and let a layer above us break
+  // samples into pieces if they wish to use the HLS standard.
+  subsample_size_.push_back(SampleSize(0, 160+16));
+  FindTotalSize();
+  vector<uint8_t> unencryptedData(total_size_);
+  vector<uint8_t> encryptedData(total_size_);
+  vector<uint8_t> encryptionIv(AES_BLOCK_SIZE);
+  vector<uint8_t> key(AES_BLOCK_SIZE);
+  EXPECT_EQ(OEMCrypto_SUCCESS,
+            OEMCrypto_GetRandom(&encryptionIv[0], AES_BLOCK_SIZE));
+  EXPECT_EQ(OEMCrypto_SUCCESS,
+            OEMCrypto_GetRandom(&key[0], AES_BLOCK_SIZE));
+  for (size_t i = 0; i < total_size_; i++) unencryptedData[i] = i % 256;
+  EncryptData(key, encryptionIv, unencryptedData, &encryptedData);
+  TestDecryptCENC(key, encryptionIv, encryptedData, unencryptedData);
+}
+
+TEST_P(OEMCryptoSessionTestsDecryptTests, OneBlock) {
+  subsample_size_.push_back(SampleSize(0, 16));
+  FindTotalSize();
+  vector<uint8_t> unencryptedData(total_size_);
+  vector<uint8_t> encryptedData(total_size_);
+  vector<uint8_t> encryptionIv(AES_BLOCK_SIZE);
+  vector<uint8_t> key(AES_BLOCK_SIZE);
+  EXPECT_EQ(OEMCrypto_SUCCESS,
+            OEMCrypto_GetRandom(&encryptionIv[0], AES_BLOCK_SIZE));
+  EXPECT_EQ(OEMCrypto_SUCCESS,
+            OEMCrypto_GetRandom(&key[0], AES_BLOCK_SIZE));
+  for (size_t i = 0; i < total_size_; i++) unencryptedData[i] = i % 256;
+  EncryptData(key, encryptionIv, unencryptedData, &encryptedData);
+  TestDecryptCENC(key, encryptionIv, encryptedData, unencryptedData);
+}
+
 // This tests the ability to decrypt multiple subsamples with no offset.
 // There is no offset within the block, used by CTR mode.  However, there might
 // be an offset in the encrypt/skip pattern.
@@ -2873,6 +2909,9 @@ INSTANTIATE_TEST_CASE_P(
            PatternTestVariant(3, 7, 0, OEMCrypto_CipherMode_CBC),
            PatternTestVariant(3, 7, 2, OEMCrypto_CipherMode_CBC),
            PatternTestVariant(7, 3, 2, OEMCrypto_CipherMode_CBC),
+           // HLS Edge case.  We should follow the CENC spec, not HLS spec.
+           PatternTestVariant(9, 1, 0, OEMCrypto_CipherMode_CBC),
+           PatternTestVariant(1, 9, 0, OEMCrypto_CipherMode_CBC),
            // Pattern length should be 10, but that is not guaranteed.
            PatternTestVariant(5, 3, 2, OEMCrypto_CipherMode_CTR),
            PatternTestVariant(1, 3, 0, OEMCrypto_CipherMode_CTR),