The import resolution for namespace packages was wrong

With this change we can now include all parents of the script, which will make
relative imports always work.

Now the whole meta_path is scanned and not just importlib's PathFinder.

Fixes #1183.

test/test_evaluate/test_namespace_package.py

@@ -1,6 +1,9 @@
 from os.path import dirname, join
 
 import pytest
+import py
+
+from ..helpers import get_example_dir
 
 
 SYS_PATH = [join(dirname(__file__), d)
@@ -72,3 +75,19 @@ def test_nested_namespace_package(Script):
     result = script.goto_definitions()
 
     assert len(result) == 1
+
+
+def test_relative_import(Script, tmpdir):
+    """
+    Attempt a relative import in a very simple namespace package.
+    """
+    directory = get_example_dir('namespace_package_relative_import')
+    # Need to copy the content in a directory where there's no __init__.py.
+    py.path.local(directory).copy(tmpdir)
+    file_path = join(tmpdir.strpath, "rel1.py")
+    script = Script(path=file_path, line=1)
+    d, = script.goto_definitions()
+    assert d.name == 'int'
+    d, = script.goto_assignments()
+    assert d.name == 'name'
+    assert d.module_name == 'rel2'