### Question:
LineApiClientImpl implements LineApiClient { @Override @NonNull public LineApiResponse<LineAccessToken> getCurrentAccessToken() { InternalAccessToken internalAccessToken; try { internalAccessToken = accessTokenCache.getAccessToken(); } catch (Exception exception) { return LineApiResponse.createAsError( LineApiResponseCode.INTERNAL_ERROR, new LineApiError("get access token fail:" + exception.getMessage()) ); } if (internalAccessToken == null) { return LineApiResponse.createAsError( LineApiResponseCode.INTERNAL_ERROR, new LineApiError("The cached access token does not exist.")); } return LineApiResponse.createAsSuccess(new LineAccessToken( internalAccessToken.getAccessToken(), internalAccessToken.getExpiresInMillis(), internalAccessToken.getIssuedClientTimeMillis())); } LineApiClientImpl(
            @NonNull String channelId,
            @NonNull LineAuthenticationApiClient oauthApiClient,
            @NonNull TalkApiClient talkApiClient,
            @NonNull AccessTokenCache accessTokenCache); @Override @NonNull LineApiResponse<?> logout(); @Override @NonNull LineApiResponse<LineAccessToken> refreshAccessToken(); @Override @NonNull LineApiResponse<LineCredential> verifyToken(); @Override @NonNull LineApiResponse<LineAccessToken> getCurrentAccessToken(); @Override @TokenAutoRefresh @NonNull LineApiResponse<LineProfile> getProfile(); @Override @TokenAutoRefresh @NonNull LineApiResponse<LineFriendshipStatus> getFriendshipStatus(); @Override @TokenAutoRefresh @NonNull LineApiResponse<GetFriendsResponse> getFriends(
            @NonNull FriendSortField sort,
            @Nullable String nextPageRequestToken); @Override @TokenAutoRefresh @NonNull LineApiResponse<GetFriendsResponse> getFriends(
            @NonNull FriendSortField sort,
            @Nullable String nextPageRequestToken,
            boolean isForOttShareMessage); @Override @TokenAutoRefresh @NonNull LineApiResponse<GetFriendsResponse> getFriendsApprovers(
            FriendSortField sort,
            @Nullable String nextPageRequestToken); @Override @TokenAutoRefresh @NonNull LineApiResponse<GetGroupsResponse> getGroups(@Nullable String nextPageRequestToken); @Override @TokenAutoRefresh @NonNull LineApiResponse<GetGroupsResponse> getGroups(
            @Nullable String nextPageRequestToken,
            boolean isForOttShareMessage); @Override @TokenAutoRefresh @NonNull LineApiResponse<GetFriendsResponse> getGroupApprovers(
            @NonNull String groupId,
            @Nullable String nextPageRequestToken); @Override @TokenAutoRefresh @NonNull LineApiResponse<String> sendMessage(
            @NonNull String targetUserId,
            @NonNull List<MessageData> messages); @Override @TokenAutoRefresh @NonNull LineApiResponse<List<SendMessageResponse>> sendMessageToMultipleUsers(
            @NonNull List<String> targetUserIds,
            @NonNull List<MessageData> messages); @Override @TokenAutoRefresh @NonNull LineApiResponse<List<SendMessageResponse>> sendMessageToMultipleUsers(
            @NonNull List<String> targetUserIds,
            @NonNull List<MessageData> messages,
            boolean isOttUsed); @NonNull LineApiResponse<Boolean> getOpenChatAgreementStatus(); @NonNull LineApiResponse<OpenChatRoomInfo> createOpenChatRoom(@NonNull OpenChatParameters openChatParameters); @NonNull LineApiResponse<Boolean> joinOpenChatRoom(@NonNull String roomId, @NonNull String displayName); @NonNull LineApiResponse<OpenChatRoomStatus> getOpenChatRoomStatus(@NonNull String roomId); @NonNull LineApiResponse<MembershipStatus> getOpenChatMembershipStatus(@NonNull String roomId); @NonNull LineApiResponse<OpenChatRoomJoinType> getOpenChatRoomJoinType(@NonNull String roomId);  }### Answer:
@Test public void testGetCurrentAccessToken() { LineApiResponse<LineAccessToken> response; LineAccessToken actualAccessToken; response = target.getCurrentAccessToken(); assertFalse(response.isSuccess()); accessTokenCache.saveAccessToken(ACCESS_TOKEN); response = target.getCurrentAccessToken(); assertTrue(response.isSuccess()); actualAccessToken = response.getResponseData(); assertNotNull(actualAccessToken); assertEquals(ACCESS_TOKEN.getAccessToken(), actualAccessToken.getTokenString()); assertEquals(ACCESS_TOKEN.getExpiresInMillis(), actualAccessToken.getExpiresInMillis()); assertEquals(ACCESS_TOKEN.getIssuedClientTimeMillis(), actualAccessToken.getIssuedClientTimeMillis()); }