diff --git a/python/testData/dotNet/PythonLibs.dll b/python/testData/dotNet/PythonLibs.dll
index cfdfa746d3a8..0736ed47a64b 100644
Binary files a/python/testData/dotNet/PythonLibs.dll and b/python/testData/dotNet/PythonLibs.dll differ
diff --git a/python/testData/dotNet/SingleNameSpace.dll b/python/testData/dotNet/SingleNameSpace.dll
index da6dacb065f6..3a6a71ecba2e 100644
Binary files a/python/testData/dotNet/SingleNameSpace.dll and b/python/testData/dotNet/SingleNameSpace.dll differ
diff --git a/python/testData/dotNet/dllSources/PythonLibs/LikeJavaClass.cs b/python/testData/dotNet/dllSources/PythonLibs/LikeJavaClass.cs
new file mode 100644
index 000000000000..a99b78cc3830
--- /dev/null
+++ b/python/testData/dotNet/dllSources/PythonLibs/LikeJavaClass.cs
@@ -0,0 +1,17 @@
+using System;
+
+namespace com.just.like.java
+{
+    public class LikeJavaClass
+    {
+        public static void likeJavaStaticMethod(int i)
+        {
+            Console.Write(i + 1);
+        }
+
+        public int likeJavaInstanceMethod(int i)
+        {
+            return i - 1;
+        }
+    }
+}
\ No newline at end of file
diff --git a/python/testData/dotNet/dllSources/PythonLibs/Properties/AssemblyInfo.cs b/python/testData/dotNet/dllSources/PythonLibs/Properties/AssemblyInfo.cs
new file mode 100644
index 000000000000..8558471bcc37
--- /dev/null
+++ b/python/testData/dotNet/dllSources/PythonLibs/Properties/AssemblyInfo.cs
@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following 
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle("PythonLibs")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("JetBrains")]
+[assembly: AssemblyProduct("PythonLibs")]
+[assembly: AssemblyCopyright("Copyright ©  2019")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible 
+// to COM components.  If you need to access a type in this assembly from 
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible(false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid("5f3a396c-3de2-48a6-91db-418b6c9e1bbb")]
+
+// Version information for an assembly consists of the following four values:
+//
+//      Major Version
+//      Minor Version 
+//      Build Number
+//      Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers 
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]
diff --git a/python/testData/dotNet/dllSources/PythonLibs/PythonLibs.csproj b/python/testData/dotNet/dllSources/PythonLibs/PythonLibs.csproj
new file mode 100644
index 000000000000..51217632c4c8
--- /dev/null
+++ b/python/testData/dotNet/dllSources/PythonLibs/PythonLibs.csproj
@@ -0,0 +1,59 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{5F3A396C-3DE2-48A6-91DB-418B6C9E1BBB}</ProjectGuid>
+    <OutputType>Library</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>PythonLibs</RootNamespace>
+    <AssemblyName>PythonLibs</AssemblyName>
+    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>..\..\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <PlatformTarget>x64</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>..\..\</OutputPath>
+    <DefineConstants>
+    </DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <PlatformTarget>x64</PlatformTarget>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="LikeJavaClass.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <PropertyGroup>
+    <PostBuildEvent>cmd /C del *.pdb</PostBuildEvent>
+  </PropertyGroup>
+  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
+       Other similar extension points exist, see Microsoft.Common.targets.
+  <Target Name="BeforeBuild">
+  </Target>
+  <Target Name="AfterBuild">
+  </Target>
+  -->
+</Project>
\ No newline at end of file
diff --git a/python/testData/dotNet/dllSources/README.txt b/python/testData/dotNet/dllSources/README.txt
new file mode 100644
index 000000000000..a0869bffc4c3
--- /dev/null
+++ b/python/testData/dotNet/dllSources/README.txt
@@ -0,0 +1,5 @@
+VS sln builds .dll files from .cs files.
+Make sure .net version is the same as one used by IronPython.
+AfterBuild action deletes .pdb files.
+
+Build with Studio or with cmd: "msbuild dllSources.sln  /t:Rebuild /p:Configuration=Release"
\ No newline at end of file
diff --git a/python/testData/dotNet/dllSources/SingleNameSpace/Deep.cs b/python/testData/dotNet/dllSources/SingleNameSpace/Deep.cs
new file mode 100644
index 000000000000..25f16a086ca1
--- /dev/null
+++ b/python/testData/dotNet/dllSources/SingleNameSpace/Deep.cs
@@ -0,0 +1,9 @@
+namespace SingleNameSpace.Some.Deep
+{
+    public class WeHaveClass
+    {
+        public class MyClass
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/python/testData/dotNet/dllSources/SingleNameSpace/SingleNameSpace.cs b/python/testData/dotNet/dllSources/SingleNameSpace/SingleNameSpace.cs
new file mode 100644
index 000000000000..e5c161a52957
--- /dev/null
+++ b/python/testData/dotNet/dllSources/SingleNameSpace/SingleNameSpace.cs
@@ -0,0 +1,11 @@
+
+namespace SingleNameSpace
+{
+    public class MyClass
+    {
+    }
+
+    public class AnotherClass
+    {
+    }
+}
\ No newline at end of file
diff --git a/python/testData/dotNet/dllSources/SingleNameSpace/SingleNameSpace.csproj b/python/testData/dotNet/dllSources/SingleNameSpace/SingleNameSpace.csproj
new file mode 100644
index 000000000000..d6164d46f9cb
--- /dev/null
+++ b/python/testData/dotNet/dllSources/SingleNameSpace/SingleNameSpace.csproj
@@ -0,0 +1,59 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{9B61AF9B-D0C6-4BC9-A200-CA79FCA4D4FF}</ProjectGuid>
+    <OutputType>Library</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>SingleNameSpace</RootNamespace>
+    <AssemblyName>SingleNameSpace</AssemblyName>
+    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>..\..\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <PlatformTarget>x64</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>..\..\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <PlatformTarget>x64</PlatformTarget>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Deep.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="SingleNameSpace.cs" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <PropertyGroup>
+    <PostBuildEvent>cmd /C del *.pdb</PostBuildEvent>
+  </PropertyGroup>
+  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
+       Other similar extension points exist, see Microsoft.Common.targets.
+  <Target Name="BeforeBuild">
+  </Target>
+  <Target Name="AfterBuild">
+  </Target>
+  -->
+</Project>
\ No newline at end of file
diff --git a/python/testData/dotNet/dllSources/dllSources.sln b/python/testData/dotNet/dllSources/dllSources.sln
new file mode 100644
index 000000000000..58977f74182a
--- /dev/null
+++ b/python/testData/dotNet/dllSources/dllSources.sln
@@ -0,0 +1,28 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 14
+VisualStudioVersion = 14.0.25420.1
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SingleNameSpace", "SingleNameSpace\SingleNameSpace.csproj", "{9B61AF9B-D0C6-4BC9-A200-CA79FCA4D4FF}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "PythonLibs", "PythonLibs\PythonLibs.csproj", "{5F3A396C-3DE2-48A6-91DB-418B6C9E1BBB}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{9B61AF9B-D0C6-4BC9-A200-CA79FCA4D4FF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9B61AF9B-D0C6-4BC9-A200-CA79FCA4D4FF}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9B61AF9B-D0C6-4BC9-A200-CA79FCA4D4FF}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9B61AF9B-D0C6-4BC9-A200-CA79FCA4D4FF}.Release|Any CPU.Build.0 = Release|Any CPU
+		{5F3A396C-3DE2-48A6-91DB-418B6C9E1BBB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{5F3A396C-3DE2-48A6-91DB-418B6C9E1BBB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{5F3A396C-3DE2-48A6-91DB-418B6C9E1BBB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{5F3A396C-3DE2-48A6-91DB-418B6C9E1BBB}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+EndGlobal