adds merge and fixes test for duplicate

src/Piwigo.Client.Tests/Piwigo.Client.Tests.csproj

@@ -56,7 +56,13 @@
       <None Update="TagApiTests.GetListAsync_should_return_all_tags.verified.txt">
         <DependentUpon>TagApiTests.cs</DependentUpon>
       </None>
-      <None Update="TagApiTests.Duplicate_should_pass_correct_parameters.verified.txt">
+      <None Update="TagApi.Merge.json">
+        <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+      </None>
+      <None Update="TagApiTests.MergeAsync_should_pass_correct_parameters.verified.txt">
+        <DependentUpon>TagApiTests.cs</DependentUpon>
+      </None>
+      <None Update="TagApiTests.DuplicateAsync_should_pass_correct_parameters.verified.txt">
         <DependentUpon>TagApiTests.cs</DependentUpon>
       </None>
     </ItemGroup>

src/Piwigo.Client.Tests/TagApi.Merge.json

@@ -0,0 +1,13 @@
+{
+  "stat": "ok",
+  "result": {
+    "destination_tag": 1,
+    "deleted_tag": [
+      3
+    ],
+    "images_in_merged_tag": [
+      "4",
+      "3"
+    ]
+  }
+}

src/Piwigo.Client.Tests/TagApiTests.MergeAsync_should_pass_correct_parameters.verified.txt

@@ -0,0 +1,10 @@
+{
+  destination_tag: 1,
+  deleted_tag: [
+    3
+  ],
+  images_in_merged_tag: [
+    4,
+    3
+  ]
+}

src/Piwigo.Client.Tests/TagApiTests.cs

@@ -78,4 +78,19 @@ public class TagApiTests : ApiTestsBase
 
         await Verify(response);
     }
+
+    [Test]
+    public async Task MergeAsync_should_pass_correct_parameters()
+    {
+        await SetJsonResultFromFileAsync("TagApi.Merge.json");
+
+        var response = await _tagApi.MergeAsync(1, 4, ApiToken);
+
+        CorrectMethodShouldGetCalled("pwg.tags.merge");
+        CorrectParamShouldGetSent("destination_tag_id", "1");
+        CorrectParamShouldGetSent("merge_tag_id", "4");
+        CorrectParamShouldGetSent("pwg_token", ApiToken);
+
+        await Verify(response);
+    }
 }

src/Piwigo.Client/Tags/ITagApi.cs

@@ -53,4 +53,16 @@ public interface ITagApi
     /// </param>
     /// <returns>all tags with at least one image assigned</returns>
     Task<IReadOnlyCollection<AssignedTag>> GetListAsync(bool? sortByCounter = null, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    ///     Merges two existing tags
+    /// </summary>
+    /// <param name="targetTagId">The tag where the images should get merged into</param>
+    /// <param name="sourceTagId">The tag that will get obsolete</param>
+    /// <param name="apiToken">The API token that can be read from <see cref="Piwigo.Client.Session.SessionStatus" /></param>
+    /// <param name="cancellationToken">
+    ///     <see cref="CancellationToken" />
+    /// </param>
+    /// <returns></returns>
+    Task<MergeResult> MergeAsync(int targetTagId, int sourceTagId, string apiToken, CancellationToken cancellationToken = default);
 }

src/Piwigo.Client/Tags/MergeResult.cs

@@ -0,0 +1,15 @@
+using Newtonsoft.Json;
+
+namespace Piwigo.Client.Tags;
+
+public record MergeResult
+{
+    [JsonProperty("destination_tag")]
+    public int DestinationTagId { get; init; }
+
+    [JsonProperty("deleted_tag")]
+    public IReadOnlyCollection<int>? DeletedTags { get; init; }
+
+    [JsonProperty("images_in_merged_tag")]
+    public IReadOnlyCollection<int>? ImagesInMergedTag { get; init; }
+}

src/Piwigo.Client/Tags/TagApi.cs

@@ -62,4 +62,18 @@ public class TagApi : ITagApi
 
         return response.Result;
     }
+
+    public async Task<MergeResult> MergeAsync(int targetTagId, int sourceTagId, string apiToken, CancellationToken cancellationToken = default)
+    {
+        var formParams = new Dictionary<string, string>
+        {
+            { "destination_tag_id", targetTagId.ToString() },
+            { "merge_tag_id", sourceTagId.ToString() },
+            { "pwg_token", apiToken }
+        };
+
+        var response = await _context.PostAsync<PiwigoResponse<MergeResult>>(_logger, "pwg.tags.merge", formParams, cancellationToken);
+
+        return response.Result;
+    }
 }