Fix missing json property name to deserialize issue channel token response correctly (#337)

Author: imasahiro

line-bot-api-client/src/test/java/com/linecorp/bot/client/LineOAuthClientTest.java

@@ -44,6 +44,13 @@ public class LineOAuthClientTest {
     }
 
     private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
+    private static final String ISSUE_TOKEN_RESPONSE_JSON =
+            "{\"access_token\":\"accessToken\",\"expires_in\":30,\"token_type\":\"Bearer\"}";
+    private static final IssueChannelAccessTokenResponse ISSUE_TOKEN_RESPONSE =
+            IssueChannelAccessTokenResponse.builder()
+                                           .expiresInSecs(30)
+                                           .accessToken("accessToken")
+                                           .build();
 
     private MockWebServer mockWebServer;
     private LineOAuthClient target;
@@ -64,15 +71,10 @@ public void tearDown() throws Exception {
 
     @Test
     public void issueToken() throws Exception {
-        final IssueChannelAccessTokenResponse mockResponse =
-                IssueChannelAccessTokenResponse.builder()
-                                               .expiresInSecs(30)
-                                               .accessToken("accessToken")
-                                               .build();
 
         mockWebServer.enqueue(new MockResponse()
                                       .setResponseCode(200)
-                                      .setBody(OBJECT_MAPPER.writeValueAsString(mockResponse)));
+                                      .setBody(ISSUE_TOKEN_RESPONSE_JSON));
 
         // Do
         final IssueChannelAccessTokenResponse actualResponse =
@@ -88,7 +90,7 @@ public void issueToken() throws Exception {
                 .isEqualTo("/v2/oauth/accessToken");
         assertThat(recordedRequest.getBody().readUtf8())
                 .isEqualTo("grant_type=client_credentials&client_id=clientId&client_secret=clientSecret");
-        assertThat(actualResponse).isEqualTo(mockResponse);
+        assertThat(actualResponse).isEqualTo(ISSUE_TOKEN_RESPONSE);
     }
 
     @Test

line-bot-model/src/main/java/com/linecorp/bot/model/oauth/IssueChannelAccessTokenResponse.java

@@ -16,6 +16,7 @@
 
 package com.linecorp.bot.model.oauth;
 
+import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 import com.fasterxml.jackson.databind.annotation.JsonPOJOBuilder;
 
@@ -31,17 +32,20 @@ public class IssueChannelAccessTokenResponse {
     /**
      * A short-lived channel access token. Valid for 30 days. Note: Channel access tokens cannot be refreshed.
      */
+    @JsonProperty("access_token")
     String accessToken;
 
     /**
      * Time until channel access token expires in seconds from time the token is issued.
      */
+    @JsonProperty("expires_in")
     int expiresInSecs;
 
     /**
      * A token type.
      */
     @Builder.Default
+    @JsonProperty("token_type")
     String tokenType = "Bearer";
 
     @JsonPOJOBuilder(withPrefix = "")