diff --git a/PWManager.UnitTests/Services/GroupServiceTest.cs b/PWManager.UnitTests/Services/GroupServiceTest.cs
new file mode 100644
index 0000000..8c7c2d0
--- /dev/null
+++ b/PWManager.UnitTests/Services/GroupServiceTest.cs
@@ -0,0 +1,94 @@
+using NSubstitute;
+using NSubstitute.ReceivedExtensions;
+using PWManager.Application.Context;
+using PWManager.Application.Exceptions;
+using PWManager.Application.Services;
+using PWManager.Domain.Entities;
+using PWManager.Domain.Repositories;
+
+namespace PWManager.UnitTests.Services; 
+
+public class GroupServiceTest {
+
+    private GroupService _sut;
+
+    [Fact]
+    public void GroupService_Should_AddGroup() {
+        var groupRepo = MockGroupRepo();
+        
+        _sut = new GroupService(null, groupRepo);
+        
+        _sut.AddGroup("userIdlel", "NewIdentifier");
+
+        groupRepo.Received().AddGroup(Arg.Is<Group>(e => e.Identifier == "NewIdentifier" && e.UserId == "userIdlel"));
+    }
+
+    [Fact]
+    public void GroupService_ShouldNot_AddExistingGroup() {
+        var groupRepo = MockGroupRepo();
+        groupRepo.GetGroup(Arg.Any<string>()).Returns(new Group("", ""));
+
+        _sut = new GroupService(null, groupRepo);
+
+        var ex = Assert.Throws<UserFeedbackException>(() => _sut.AddGroup("yes", "yes"));
+        
+        Assert.Equal(MessageStrings.GroupAlreadyExist("yes"), ex.Message);
+    }
+
+    [Fact]
+    public void GroupService_Should_DeleteGroup() {
+        var repo = MockGroupRepo();
+        
+        _sut = new GroupService(null, repo);
+        
+        _sut.DeleteGroup("identifier");
+
+        repo.Received().RemoveGroup(Arg.Is<string>(e => e == "identifier"));
+    }
+
+    [Fact]
+    public void GroupService_ShouldNot_DeleteGroupFailed() {
+        var repo = MockGroupRepo();
+        repo.RemoveGroup(Arg.Any<string>()).Returns(false);
+
+        _sut = new GroupService(null, repo);
+        
+        var ex = Assert.Throws<UserFeedbackException>(() => _sut.DeleteGroup("identifier"));
+        
+        Assert.Equal(MessageStrings.FailedDeletingGroup("identifier"), ex.Message);
+    }
+
+    [Fact]
+    public void GroupService_Should_GetAllNames() {
+        var repo = MockGroupRepo();
+
+        _sut = new GroupService(null, repo);
+
+        var names = _sut.GetAllGroupNames();
+        
+        Assert.Equal(2, names.Count);
+        Assert.Equal("Name1", names[0]);
+        Assert.Equal("Name2", names[1]);
+    }
+
+    [Fact]
+    public void GroupService_Should_SwitchGroup() {
+        var env = Substitute.For<IUserEnvironment>();
+        var repo = MockGroupRepo();
+        var group = new Group("a", "asd");
+        repo.GetGroup(Arg.Any<string>()).Returns(group);
+
+        _sut = new GroupService(env, repo);
+
+        _sut.SwitchGroup("a");
+        
+        env.Received().CurrentGroup = group;
+    }
+
+    private IGroupRepository MockGroupRepo() {
+        var groupRepo = Substitute.For<IGroupRepository>();
+        groupRepo.RemoveGroup(Arg.Any<string>()).Returns(true);
+        groupRepo.GetAllGroupNames().Returns(new List<string> { "Name1", "Name2" });
+        return groupRepo;
+    }
+}
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