Unit test for OEMCrypto_LoadUsageEntry in multiple sessions

Merge from Widevine repo of http://go/wvgerrit/95283

If an entry is loaded in a second session, the error should be
OEMCrypto_ERROR_INVALID_SESSION.

Bug: 150647218
Test: ran unit tests
  Change-Id: I4e666ce6626303a36b16997f0a012d57a7039697
Change-Id: Id0e73dec5879ec9ec4e8ab8ebe1590c568e7f0af

libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp

@@ -5178,6 +5178,32 @@ TEST_P(OEMCryptoUsageTableTest, CreateAndLoadMultipleEntriesAPI16) {
       OEMCrypto_CreateNewUsageEntry(s2.session_id(), &usage_entry_number));
 }
 
+// An entry can be loaded in only one session at a time.
+TEST_P(OEMCryptoUsageTableTest, LoadEntryInMultipleSessions) {
+  // Entry Count: we start each test with an empty header.
+  LicenseWithUsageEntry entry;
+  entry.license_messages().set_api_version(license_api_version_);
+  Session& s = entry.session();
+  // Make first entry 0.
+  ASSERT_NO_FATAL_FAILURE(entry.MakeOfflineAndClose(this));
+  const uint32_t usage_entry_number = s.usage_entry_number();
+  EXPECT_EQ(usage_entry_number, 0u);  // Should be only entry in this test.
+
+  // Load an entry, then try to create a second.
+  ASSERT_NO_FATAL_FAILURE(s.open());
+  // Reload entry 0.
+  ASSERT_NO_FATAL_FAILURE(s.ReloadUsageEntry());
+
+  // Create an entry, then try to load a second.
+  Session s2;
+  ASSERT_NO_FATAL_FAILURE(s2.open());
+  // Try to load entry 0 into session 2.
+  ASSERT_EQ(OEMCrypto_ERROR_INVALID_SESSION,
+            OEMCrypto_LoadUsageEntry(s2.session_id(), usage_entry_number,
+                                     s.encrypted_usage_entry().data(),
+                                     s.encrypted_usage_entry().size()));
+}
+
 // Test generic encrypt when the license uses a PST.
 TEST_P(OEMCryptoUsageTableTest, GenericCryptoEncrypt) {
   LicenseWithUsageEntry entry;