gh-108303: Move all doctest related files and tests to Lib/test/test_doctest/

Doc/library/doctest.rst

@@ -134,7 +134,7 @@ That's all you need to know to start making productive use of :mod:`doctest`!
 Jump in.  The following sections provide full details.  Note that there are many
 examples of doctests in the standard Python test suite and libraries.
 Especially useful examples can be found in the standard test file
-:file:`Lib/test/test_doctest.py`.
+:file:`Lib/test/test_doctest/test_doctest.py`.
 
 
 .. _doctest-simple-testmod:

Lib/test/libregrtest/findtests.py

@@ -19,6 +19,7 @@
 SPLITTESTDIRS: set[TestName] = {
     "test_asyncio",
     "test_concurrent_futures",
+    "test_doctests",
     "test_future_stmt",
     "test_gdb",
     "test_inspect",

Lib/test/support/pty_helper.py

@@ -58,3 +58,23 @@ def terminate(proc):
                         input = b""  # Stop writing
                     if not input:
                         sel.modify(master, selectors.EVENT_READ)
+
+
+######################################################################
+## Fake stdin (for testing interactive debugging)
+######################################################################
+
+class FakeInput:
+    """
+    A fake input stream for pdb'sx interactive debugger.  Whenever a
+    line is read, print it (to simulate the user typing it), and then
+    return it.  The set of lines to return is specified in the
+    constructor; they should not have trailing newlines.
+    """
+    def __init__(self, lines):
+        self.lines = lines
+
+    def readline(self):
+        line = self.lines.pop(0)
+        print(line)
+        return line+'\n'

Lib/test/test_doctest/__init__.py

@@ -0,0 +1,5 @@
+import os
+from test.support import load_package_tests
+
+def load_tests(*args):
+    return load_package_tests(os.path.dirname(__file__), *args)

Lib/test/sample_doctest.py → Lib/test/test_doctest/sample_doctest.py

@@ -32,8 +32,8 @@ def bar():
 def test_silly_setup():
     """
 
-    >>> import test.test_doctest
-    >>> test.test_doctest.sillySetup
+    >>> import test.test_doctest.test_doctest
+    >>> test.test_doctest.test_doctest.sillySetup
     True
     """