[oauth] Fix access token serialization/deserialization

bundles/org.openhab.core.auth.oauth2client/pom.xml

@@ -25,6 +25,12 @@
       <artifactId>org.openhab.core.io.net</artifactId>
       <version>${project.version}</version>
     </dependency>
+    <dependency>
+      <groupId>org.openhab.core.bundles</groupId>
+      <artifactId>org.openhab.core.test</artifactId>
+      <version>${project.version}</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
 </project>

bundles/org.openhab.core.auth.oauth2client/src/main/java/org/openhab/core/auth/oauth2client/internal/OAuthStoreHandlerImpl.java

@@ -15,7 +15,10 @@
 import static org.openhab.core.auth.oauth2client.internal.StorageRecordType.*;
 
 import java.security.GeneralSecurityException;
+import java.time.Instant;
 import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.format.DateTimeParseException;
 import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.Map;
@@ -236,13 +239,17 @@ private class StorageFacade implements AutoCloseable {
 
         public StorageFacade(Storage<String> storage) {
             this.storage = storage;
-            // Add adapters for LocalDateTime
+            // Add adapters for Instant
             gson = new GsonBuilder()
-                    .registerTypeAdapter(LocalDateTime.class,
-                            (JsonDeserializer<LocalDateTime>) (json, typeOfT, context) -> LocalDateTime
-                                    .parse(json.getAsString()))
-                    .registerTypeAdapter(LocalDateTime.class,
-                            (JsonSerializer<LocalDateTime>) (date, type,
+                    .registerTypeAdapter(Instant.class, (JsonDeserializer<Instant>) (json, typeOfT, context) -> {
+                        try {
+                            return Instant.parse(json.getAsString());
+                        } catch (DateTimeParseException e) {
+                            return LocalDateTime.parse(json.getAsString()).atZone(ZoneId.systemDefault()).toInstant();
+                        }
+                    })
+                    .registerTypeAdapter(Instant.class,
+                            (JsonSerializer<Instant>) (date, type,
                                     jsonSerializationContext) -> new JsonPrimitive(date.toString()))
                     .setPrettyPrinting().create();
         }

bundles/org.openhab.core.auth.oauth2client/src/test/java/org/openhab/core/auth/oauth2client/OAuthStoreHandlerTest.java

@@ -0,0 +1,98 @@
+/**
+ * Copyright (c) 2010-2022 Contributors to the openHAB project
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.openhab.core.auth.oauth2client;
+
+import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+
+import java.io.IOException;
+import java.security.GeneralSecurityException;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.mockito.junit.jupiter.MockitoSettings;
+import org.mockito.quality.Strictness;
+import org.openhab.core.auth.client.oauth2.AccessTokenResponse;
+import org.openhab.core.auth.oauth2client.internal.OAuthStoreHandlerImpl;
+import org.openhab.core.auth.oauth2client.internal.StorageRecordType;
+import org.openhab.core.storage.Storage;
+import org.openhab.core.storage.StorageService;
+import org.openhab.core.test.storage.VolatileStorage;
+
+/**
+ * The {@link OAuthStoreHandlerTest} contains tests for
+ * {@link org.openhab.core.auth.oauth2client.OAuthStoreHandlerImpl}
+ *
+ * @author Jacob Laursen - Initial contribution
+ */
+@ExtendWith(MockitoExtension.class)
+@MockitoSettings(strictness = Strictness.LENIENT)
+@NonNullByDefault
+public class OAuthStoreHandlerTest {
+    private @Mock @NonNullByDefault({}) StorageService storageService;
+
+    private static final String STORE_NAME = "StorageHandler.For.OAuthClientService";
+    private @NonNullByDefault({}) Storage<String> storage;
+    private @NonNullByDefault({}) OAuthStoreHandlerImpl storeHandler;
+
+    @BeforeEach
+    public void initialize() throws IOException {
+        storage = new VolatileStorage<>();
+        Mockito.doReturn(storage).when(storageService).getStorage(STORE_NAME);
+        storeHandler = new OAuthStoreHandlerImpl(storageService);
+    }
+
+    @Test
+    public void loadAccessTokenResponseWhenCreatedOnIsLocalDateTime() throws GeneralSecurityException {
+        final String handle = "test";
+        final String createdOn = "2022-08-14T21:21:05.568991";
+        final Instant expected = LocalDateTime.parse(createdOn).atZone(ZoneId.systemDefault()).toInstant();
+
+        storage.put(StorageRecordType.ACCESS_TOKEN_RESPONSE.getKey(handle), getJsonforCreatedOn(createdOn));
+        AccessTokenResponse response = storeHandler.loadAccessTokenResponse(handle);
+
+        assertThat(response, is(notNullValue()));
+        if (response != null) {
+            assertThat(response.getCreatedOn(), is(expected));
+        }
+    }
+
+    @Test
+    public void loadAccessTokenResponseWhenCreatedOnIsInstant() throws GeneralSecurityException {
+        final String handle = "test";
+        final String createdOn = "2022-08-14T19:21:05.568991Z";
+        final Instant expected = Instant.parse(createdOn);
+
+        storage.put(StorageRecordType.ACCESS_TOKEN_RESPONSE.getKey(handle), getJsonforCreatedOn(createdOn));
+        AccessTokenResponse response = storeHandler.loadAccessTokenResponse(handle);
+
+        assertThat(response, is(notNullValue()));
+        if (response != null) {
+            assertThat(response.getCreatedOn(), is(expected));
+        }
+    }
+
+    private String getJsonforCreatedOn(String createdOn) {
+        return "{\"accessToken\": \"x\", \"tokenType\": \"Bearer\", \"expiresIn\": 2592000, \"refreshToken\": \"x\", \"createdOn\": \""
+                + createdOn + "\"}";
+    }
+}