Add failing tests for deshaw#318

This adds a failing test.

lib/python/pyflyby/_parse.py

@@ -937,7 +937,7 @@ def __new__(cls, arg, filename=None, startpos=None, flags=None,
             return cls.from_text(
                 arg, filename=filename, startpos=startpos,
                 flags=flags, auto_flags=auto_flags)
-        raise TypeError("%s: unexpected %s"
+        raise TypeError("%r: unexpected %r"
                         % (cls.__name__, type(arg).__name__,))
 
     @classmethod

tests/test_imports2s.py

@@ -697,6 +697,29 @@ def selfref():
     assert output == expected
 
 
+def test_fix_missing_imports_other_class():
+    """
+    This insert import for type annotations, only if a class is present before.
+
+    See https://github.com/deshaw/pyflyby/issues/318
+    """
+    data = dedent("""
+    from __future__ import annotations
+
+    class _TestCls():
+        class WrappedFunction():
+            pass
+
+    class Popen():
+        def test(self) -> Popen:
+            return None""")
+    b = PythonBlock(data)
+    db = ImportDB("from subprocess import Popen")
+    output = fix_unused_and_missing_imports(b, db=db)
+    expected = PythonBlock(data)
+    assert output == expected
+
+
 def test_fix_unused_and_missing_continutation_1():
     input = PythonBlock(dedent(r'''
         a#\