diff --git a/modules/cms-kit/test/Volo.CmsKit.Application.Tests/Tags/TagAppService_Tests.cs b/modules/cms-kit/test/Volo.CmsKit.Application.Tests/Tags/TagAppService_Tests.cs
new file mode 100644
index 0000000000..35b46b5a04
--- /dev/null
+++ b/modules/cms-kit/test/Volo.CmsKit.Application.Tests/Tags/TagAppService_Tests.cs
@@ -0,0 +1,78 @@
+using Microsoft.Extensions.DependencyInjection;
+using NSubstitute;
+using Shouldly;
+using System.Threading.Tasks;
+using Volo.Abp.Clients;
+using Volo.Abp.Users;
+using Volo.Abp.Validation;
+using Volo.CmsKit.Public.Tags;
+using Xunit;
+
+namespace Volo.CmsKit.Tags
+{
+    public class TagAppService_Tests : CmsKitApplicationTestBase
+    {
+        private readonly ITagAppService _tagAppService;
+        private ICurrentUser _currentUser;
+        private readonly CmsKitTestData _cmsKitTestData;
+
+        public TagAppService_Tests()
+        {
+            _tagAppService = GetRequiredService<ITagAppService>();
+            _cmsKitTestData = GetRequiredService<CmsKitTestData>();
+        }
+
+        protected override void AfterAddApplication(IServiceCollection services)
+        {
+            _currentUser = Substitute.For<ICurrentUser>();
+            services.AddSingleton(_currentUser);
+        }
+
+        [Fact]
+        public async Task GetAllRelatedTagsAsync()
+        {
+            var list = await _tagAppService.GetAllRelatedTagsAsync(new GetRelatedTagsInput
+            {
+                EntityType = _cmsKitTestData.Content_1_EntityType,
+                EntityId = _cmsKitTestData.EntityId1
+            });
+
+            list.ShouldNotBeEmpty();
+            list.Count.ShouldBe(2);
+        }
+
+        [Fact]
+        public async Task ShouldntGet_GetAllRelatedTagsAsync()
+        {
+            var list = await _tagAppService.GetAllRelatedTagsAsync(new GetRelatedTagsInput
+            {
+                EntityType = "any_other_type",
+                EntityId = "1"
+            });
+
+            list.ShouldBeEmpty();
+        }
+
+        [Fact]
+        public async Task GetRelatedTagsAsync_ShouldThrowValidationException_WithoutEntityType()
+        {
+            await Assert.ThrowsAsync<AbpValidationException>(async () => 
+                await _tagAppService.GetAllRelatedTagsAsync(new GetRelatedTagsInput
+                {
+                    EntityType = null,
+                    EntityId = _cmsKitTestData.EntityId1
+                }));
+        }
+
+        [Fact]
+        public async Task GetRelatedTagsAsync_ShouldThrowValidationException_WithoutEntityId()
+        {
+            await Assert.ThrowsAsync<AbpValidationException>(async () => 
+                await _tagAppService.GetAllRelatedTagsAsync(new GetRelatedTagsInput
+                {
+                    EntityType = null,
+                    EntityId = _cmsKitTestData.EntityId1
+                }));
+        }
+    }
+}