diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6354607..d260836 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## v2.0.0-beta.6 - 2024-02-27
+
+- Fix prefix modification algorithm and add tests.
+
 ## v2.0.0-beta.5 - 2024-02-27
 
 - Fix prefix modification algorithm.
diff --git a/src/Nexus.Sources.Federation/Federation.cs b/src/Nexus.Sources.Federation/Federation.cs
index 6681d07..fe0ff86 100644
--- a/src/Nexus.Sources.Federation/Federation.cs
+++ b/src/Nexus.Sources.Federation/Federation.cs
@@ -15,7 +15,7 @@ namespace Nexus.Sources
     public class Federation : IDataSource
     {
         private DataSourceContext _context = default!;
-        private Api.NexusClient _nexusClient = default!;
+        private Api.INexusClient _nexusClient = default!;
         private string _sourcePath = "/";
         private string _mountPoint = default!;
         private string _includePattern = default!;
@@ -28,6 +28,9 @@ static Federation()
             _jsonSerializerOptions.Converters.Add(new JsonStringEnumConverter());
         }
 
+        public Func<HttpClient, Api.INexusClient> CreateNexusClient { get; set; } 
+            = httpClient => new Api.NexusClient(httpClient);
+
         public Task SetContextAsync(DataSourceContext context, ILogger logger, CancellationToken cancellationToken)
         {
             _context = context;
@@ -49,13 +52,13 @@ public Task SetContextAsync(DataSourceContext context, ILogger logger, Cancellat
 
             httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("bearer", token);
 
-            _nexusClient = new Api.NexusClient(httpClient);
+            _nexusClient = CreateNexusClient(httpClient);
 
             // source-path
             var sourcePath = _context.SourceConfiguration?.GetStringValue($"source-path");
 
             if (sourcePath is not null)
-                _sourcePath = sourcePath;
+                _sourcePath = '/' + sourcePath.Trim('/');
 
             // mount-point
             var mountPoint = _context.SourceConfiguration?.GetStringValue($"mount-point");
@@ -63,9 +66,9 @@ public Task SetContextAsync(DataSourceContext context, ILogger logger, Cancellat
             if (mountPoint is null)
                 throw new Exception("The mount-point property is not set.");
 
-            _mountPoint = mountPoint;
+            _mountPoint = '/' + mountPoint.Trim('/');
 
-            // source-path
+            // include-pattern
             var includePattern = _context.SourceConfiguration?.GetStringValue($"include-pattern");
             _includePattern = includePattern ?? "";
 
@@ -132,12 +135,14 @@ public async Task ReadAsync(DateTime begin, DateTime end, ReadRequest[] requests
 
         private string ToMountPointPrefixedCatalogId(string catalogId)
         {
-            return _mountPoint + catalogId.Substring(_sourcePath.Length);
+            //                     absolute, relative
+            return Path.Combine(_mountPoint, catalogId.Substring(_sourcePath.Length).TrimStart('/'));
         }
 
         private string ToSourcePathPrefixedCatalogId(string catalogId)
         {
-            return _sourcePath + catalogId.Substring(_mountPoint.Length);
+            //                     absolute, relative
+            return Path.Combine(_sourcePath, catalogId.Substring(_mountPoint.Length).TrimStart('/'));
         }
     }
 }
diff --git a/tests/Nexus.Sources.Federation.Tests/FederationTests.cs b/tests/Nexus.Sources.Federation.Tests/FederationTests.cs
index 6cf21d2..f74d9fb 100644
--- a/tests/Nexus.Sources.Federation.Tests/FederationTests.cs
+++ b/tests/Nexus.Sources.Federation.Tests/FederationTests.cs
@@ -1,7 +1,75 @@
-namespace Nexus.Sources.Tests
+using System.Text.Json;
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+using Nexus.Api;
+using Nexus.Extensibility;
+using Xunit;
+
+namespace Nexus.Sources.Tests;
+
+public class FederationTests
 {
-    public class FederationTests
+    [Theory]
+    [InlineData("/", "/", "/TEST_CATALOG")]
+    [InlineData("/src", "/", "/TEST_CATALOG")]
+    [InlineData("src", "/", "/TEST_CATALOG")]
+    [InlineData("/src/", "/", "/TEST_CATALOG")]
+    [InlineData("/src", "/mnt", "/mnt/TEST_CATALOG")]
+    [InlineData("/src/", "/mnt", "/mnt/TEST_CATALOG")]
+    [InlineData("/src", "/mnt/", "/mnt/TEST_CATALOG")]
+    [InlineData("/", "/mnt", "/mnt/TEST_CATALOG")]
+    [InlineData("/", "/mnt/", "/mnt/TEST_CATALOG")]
+    [InlineData("/", "mnt/", "/mnt/TEST_CATALOG")]
+    [InlineData(default, "mnt", "/mnt/TEST_CATALOG")]
+    [InlineData("src", "", "/TEST_CATALOG")]
+    public async Task ProvidesCatalogRegistrations(string? sourcePath, string mountPoint, string expectedCatalogId)
     {
-        
+        // arrange
+        var catalogsClient = Mock.Of<ICatalogsClient>();
+
+        Mock.Get(catalogsClient)
+            .Setup(catalog => catalog.GetChildCatalogInfosAsync(
+                It.IsAny<string>(),
+                It.IsAny<CancellationToken>()
+            ))
+            .ReturnsAsync((string catalogId, CancellationToken cancellationToken) => 
+            {
+                Assert.True(catalogId.StartsWith('/'));
+
+                var childCatalogId = catalogId == "/"
+                    ? catalogId + "TEST_CATALOG"
+                    : catalogId + "/" + "TEST_CATALOG";
+
+                var catalog = new CatalogInfo(childCatalogId, default, default, default, default, default, default, default, default, default, default, default!, default, default);
+
+                return new List<CatalogInfo>() { catalog };
+            });
+
+        var nexusClient = Mock.Of<INexusClient>();
+
+        Mock.Get(nexusClient)
+            .SetupGet(client => client.Catalogs)
+            .Returns(catalogsClient);
+
+        var dataSource = new Federation() { CreateNexusClient = _ => nexusClient } as IDataSource;
+
+        var context = new DataSourceContext(
+            ResourceLocator: new Uri("https://example.com"),
+            SystemConfiguration: default!,
+            SourceConfiguration: new Dictionary<string, JsonElement>()
+            {
+                ["access-token"] = JsonSerializer.SerializeToElement(""),
+                ["source-path"] = JsonSerializer.SerializeToElement(sourcePath),
+                ["mount-point"] = JsonSerializer.SerializeToElement(mountPoint),
+            },
+            RequestConfiguration: default!);
+
+        await dataSource.SetContextAsync(context, NullLogger.Instance, CancellationToken.None);
+
+        // act
+        var catalogRegistrations = await dataSource.GetCatalogRegistrationsAsync("/", CancellationToken.None);
+
+        // assert
+        Assert.Equal(expectedCatalogId, catalogRegistrations.First().Path);
     }
 }
\ No newline at end of file
diff --git a/tests/Nexus.Sources.Federation.Tests/Nexus.Sources.Federation.Tests.csproj b/tests/Nexus.Sources.Federation.Tests/Nexus.Sources.Federation.Tests.csproj
index 71d4230..f89d76e 100644
--- a/tests/Nexus.Sources.Federation.Tests/Nexus.Sources.Federation.Tests.csproj
+++ b/tests/Nexus.Sources.Federation.Tests/Nexus.Sources.Federation.Tests.csproj
@@ -7,6 +7,8 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
+    <PackageReference Include="Moq" Version="4.20.70" />
+    <PackageReference Include="Nexus.Extensibility" Version="2.0.0-beta.21" />
     <PackageReference Include="xunit" Version="2.7.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.5.7">
       <PrivateAssets>all</PrivateAssets>
@@ -15,13 +17,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <ProjectReference Include="..\..\src\Nexus.Sources.Federation\Nexus.Sources.Federation.csproj" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <None Update="*Database/**/*">
-      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
-    </None>
+    <ProjectReference Include="../../src/Nexus.Sources.Federation/Nexus.Sources.Federation.csproj" />
   </ItemGroup>
 
 </Project>
diff --git a/version.json b/version.json
index c8d3709..91c6cff 100644
--- a/version.json
+++ b/version.json
@@ -1,4 +1,4 @@
 {
     "version": "2.0.0",
-    "suffix": "beta.5"
+    "suffix": "beta.6"
 }
\ No newline at end of file