Get group chat summary.

src/LineBot/GroupSummary/GroupSummary.cs

@@ -0,0 +1,20 @@
+// Copyright Dirk Lemstra (https://github.com/dlemstra/line-bot-sdk-dotnet).
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using Newtonsoft.Json;
+
+namespace Line
+{
+  internal sealed class GroupSummary : IGroupSummary
+  {
+    [JsonProperty("groupId")]
+    public string GroupId { get; set; } = default!;
+
+    [JsonProperty("groupName")]
+    public string GroupName { get; set; } = default!;
+
+    [JsonProperty("pictureUrl")]
+    public Uri PictureUrl { get; set; } = default!;
+  }
+}

src/LineBot/GroupSummary/IGroupSummary.cs

@@ -0,0 +1,28 @@
+// Copyright Dirk Lemstra (https://github.com/dlemstra/line-bot-sdk-dotnet).
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+
+namespace Line
+{
+    /// <summary>
+    /// Encapsulates the interface for the summary of a group.
+    /// </summary>
+    public interface IGroupSummary
+  {
+    /// <summary>
+    /// Gets the Group ID.
+    /// </summary>
+    string GroupId { get; }
+
+    /// <summary>
+    /// Gets the Group name.
+    /// </summary>
+    string GroupName { get; }
+
+        /// <summary>
+        /// Gets the Group icon URL.
+        /// </summary>
+    Uri PictureUrl { get; }
+  }
+}

src/LineBot/ILineBot.cs

@@ -80,6 +80,20 @@ public interface ILineBot
         /// <returns>The events from the specified request.</returns>
         Task<ILineEvents> GetEvents(HttpRequest request);
 
+        /// <summary>
+        /// Returns the summary of the specified group.
+        /// </summary>
+        /// <param name="group">The group.</param>
+        /// <returns>The summary of the specified group.</returns>
+        Task<IGroupSummary?> GetGroupSummmary(IGroup group);
+
+        /// <summary>
+        /// Returns the summary of the specified group.
+        /// </summary>
+        /// <param name="groupId">The id of the group.</param>
+        /// <returns>The summary of the specified group.</returns>
+        Task<IGroupSummary?> GetGroupSummmary(string groupId);
+
         /// <summary>
         /// Returns the profile of the specified user.
         /// </summary>

src/LineBot/LineBot.cs

@@ -219,6 +219,33 @@ public async Task<ILineEvents> GetEvents(HttpRequest request)
             return eventCollection;
         }
 
+        /// <summary>
+        /// Returns the summary of the specified group.
+        /// </summary>
+        /// <param name="groupId">The id of the group.</param>
+        /// <returns>The summary of the specified group.</returns>
+        public async Task<IGroupSummary?> GetGroupSummmary(string groupId)
+        {
+            Guard.NotNullOrEmpty(nameof(groupId), groupId);
+
+            var response = await _client.GetAsync($"group/{groupId}/summary").ConfigureAwait(false);
+            await response.CheckResult().ConfigureAwait(false);
+
+            return await response.Content.DeserializeObject<GroupSummary>().ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Returns the summary of the specified group.
+        /// </summary>
+        /// <param name="group">The group.</param>
+        /// <returns>The summary of the specified group.</returns>
+        public async Task<IGroupSummary?> GetGroupSummmary(IGroup group)
+        {
+            Guard.NotNull(nameof(group), group);
+
+            return await GetGroupSummmary(group.Id);
+        }
+
         /// <summary>
         /// Returns the profile of the specified user.
         /// </summary>

tests/LineBot.Tests/GroupProfile/GroupSummaryTests.cs

@@ -0,0 +1,88 @@
+// Copyright Dirk Lemstra (https://github.com/dlemstra/line-bot-sdk-dotnet).
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Line.Tests
+{
+    [TestClass]
+    public class GroupSummaryTests
+    {
+        [TestMethod]
+        public async Task GetGroupSummmary_GroupIsNulll_ThrowsException()
+        {
+            ILineBot bot = TestConfiguration.CreateBot();
+            await ExceptionAssert.ThrowsArgumentNullExceptionAsync("group", async () =>
+            {
+                IGroupSummary summary = await bot.GetGroupSummmary((IGroup)null);
+            });
+        }
+
+        [TestMethod]
+        public async Task GetGroupSummmary_GroupIdIsNull_ThrowsException()
+        {
+            ILineBot bot = TestConfiguration.CreateBot();
+            await ExceptionAssert.ThrowsArgumentNullExceptionAsync("groupId", async () =>
+            {
+                IGroupSummary summary = await bot.GetGroupSummmary((string)null);
+            });
+        }
+
+        [TestMethod]
+        public async Task GetGroupSummmary_GroupIdIsEmpty_ThrowsException()
+        {
+            ILineBot bot = TestConfiguration.CreateBot();
+            await ExceptionAssert.ThrowsArgumentEmptyExceptionAsync("groupId", async () =>
+            {
+                IGroupSummary summary = await bot.GetGroupSummmary(string.Empty);
+            });
+        }
+
+        [TestMethod]
+        public async Task GetGroupSummmary_ErrorResponse_ThrowsException()
+        {
+            TestHttpClient httpClient = TestHttpClient.ThatReturnsAnError();
+
+            ILineBot bot = TestConfiguration.CreateBot(httpClient);
+
+            await ExceptionAssert.ThrowsUnknownError(async () =>
+            {
+                await bot.GetGroupSummmary("test");
+            });
+        }
+
+        [TestMethod]
+        [DeploymentItem(JsonDocuments.GroupSummary)]
+        public async Task GetGroupSummary_CorrectResponse_ReturnsGroupSummary()
+        {
+            TestHttpClient httpClient = TestHttpClient.Create(JsonDocuments.GroupSummary);
+
+            ILineBot bot = TestConfiguration.CreateBot(httpClient);
+            IGroupSummary summary = await bot.GetGroupSummmary("test");
+
+            Assert.AreEqual(HttpMethod.Get, httpClient.RequestMethod);
+            Assert.AreEqual("/group/test/summary", httpClient.RequestPath);
+
+            Assert.IsNotNull(summary);
+            Assert.AreEqual("Ca56f94637c...", summary.GroupId);
+            Assert.AreEqual("Group name", summary.GroupName);
+            Assert.AreEqual(new Uri("https://profile.line-scdn.net/abcdefghijklmn"), summary.PictureUrl);
+        }
+
+        [TestMethod]
+        [DeploymentItem(JsonDocuments.GroupSummary)]
+        public async Task GetGroupSummary_WithGroup_ReturnsGroupSummary()
+        {
+            TestHttpClient httpClient = TestHttpClient.Create(JsonDocuments.GroupSummary);
+
+            ILineBot bot = TestConfiguration.CreateBot(httpClient);
+            IGroupSummary summary = await bot.GetGroupSummmary(new TestGroup());
+
+            Assert.AreEqual("/group/testGroup/summary", httpClient.RequestPath);
+            Assert.IsNotNull(summary);
+        }
+    }
+}

tests/LineBot.Tests/JsonDocuments/GroupSummary.json

@@ -0,0 +1,5 @@
+{
+  "groupId": "Ca56f94637c...",
+  "groupName": "Group name",
+  "pictureUrl": "https://profile.line-scdn.net/abcdefghijklmn"
+}

tests/LineBot.Tests/JsonDocuments/JsonDocuments.cs

@@ -9,5 +9,6 @@ public static partial class JsonDocuments
         public const string Error = "JsonDocuments/Error.json";
         public const string UserProfile = "JsonDocuments/UserProfile.json";
         public const string Whitespace = "JsonDocuments/Whitespace.json";
+        public const string GroupSummary = "JsonDocuments/GroupSummary.json";
     }
 }