Environment

• Pythonnet version: 2.3.0
• Python version: 3.5 3.4
• Operating System: Ubuntu 14.04.04 64-bit
• Mono 4.6

Details

• Describe what you were trying to get done.
  I am trying to run embed_tests, but they do not run and I get 136 errors like:

18. SetUp Error : Python.EmbeddingTest.TestPyInt
    System.EntryPointNotFoundException : Py_IsInitialized
    at (wrapper managed-to-native) Python.Runtime.Runtime:Py_IsInitialized ()
    at Python.Runtime.Runtime.Initialize () [0x00001] in <6f2b25faa20d4740b2ac949a9317c3ed>:0
    at Python.Runtime.PythonEngine.Initialize (System.Collections.Generic.IEnumerable`1[T] args, System.Boolean setSysArgv) [0x00016] in <6f2b25faa20d4740b2ac949a9317c3ed>:0
    at Python.Runtime.PythonEngine.Initialize (System.Boolean setSysArgv) [0x00006] in <6f2b25faa20d4740b2ac949a9317c3ed>:0
    at Python.Runtime.PythonEngine.Initialize () [0x00001] in <6f2b25faa20d4740b2ac949a9317c3ed>:0
    at Python.EmbeddingTest.TestPyInt.SetUp () [0x00001] in :0
    at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (System.Reflection.MonoMethod,object,object[],System.Exception&)
    at System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00038] in <8f2c484307284b51944a1a13a14c0266>:0

The main point is here: "Py_IsInitialized" entry point is not found. The bug is that pythonnet does load "__Internal" library instead of libpython3.4m.so. This happens because setup.py detects if /usr/bin/python3 does link to ".so" and if not then load "__Internal". But this is wrong logic, because loading "__Internal" doesn't make any sense. Never. On Ubuntu Python Interpreter do not load libpythonXXX.so (is statically linked), but library libpythonXXX.so exists !

There are generally 2 cases on Linux:

1. pythonnet is loaded from Python Interpreter (for example /usr/bin/python3 application)
   How to check: try to resolve entry "Py_IsInitialized" in main application. If resolved then skip (2)
2. pythonnet is loaded from .NET Application
   How to check: if (1) fails then it is the case. Try to load Python library (libpythonXXX.so) in this case.

• What commands did you run to trigger this issue? If you can provide a
  Minimal, Complete, and Verifiable example
  this will help us understand the issue.

nunit3-console.exe --noresult Python.EmbeddingTest.dll