From c09087cae19706fffb4c1e1e5fe3830612f7b0fb Mon Sep 17 00:00:00 2001
From: Daniel Hahler <git@thequod.de>
Date: Mon, 21 Oct 2019 02:52:02 +0200
Subject: [PATCH 1/4] SysCapture: allow passing in stdin

---
 src/_pytest/capture.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/_pytest/capture.py b/src/_pytest/capture.py
index e4e58b32cf6..915ae58f162 100644
--- a/src/_pytest/capture.py
+++ b/src/_pytest/capture.py
@@ -633,16 +633,20 @@ def snap(self):
 
 class SysCapture:
 
+    CLOSE_STDIN = object
     EMPTY_BUFFER = str()
     _state = None
 
-    def __init__(self, fd, tmpfile=None):
+    def __init__(self, fd, tmpfile=None, stdin=CLOSE_STDIN):
         name = patchsysdict[fd]
         self._old = getattr(sys, name)
         self.name = name
         if tmpfile is None:
             if name == "stdin":
-                tmpfile = DontReadFromInput()
+                if stdin is self.CLOSE_STDIN:
+                    tmpfile = DontReadFromInput()
+                else:
+                    tmpfile = stdin
             else:
                 tmpfile = CaptureIO()
         self.tmpfile = tmpfile

From 73a998404a8d1234a1fcb0ba9a4e758ece07b45e Mon Sep 17 00:00:00 2001
From: Daniel Hahler <git@thequod.de>
Date: Mon, 21 Oct 2019 02:57:44 +0200
Subject: [PATCH 2/4] runpytest_inprocess: allow to pass in stdin

---
 src/_pytest/pytester.py | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/_pytest/pytester.py b/src/_pytest/pytester.py
index a050dad09e5..83e0910834e 100644
--- a/src/_pytest/pytester.py
+++ b/src/_pytest/pytester.py
@@ -847,7 +847,7 @@ class reprec:
             for finalizer in finalizers:
                 finalizer()
 
-    def runpytest_inprocess(self, *args, **kwargs):
+    def runpytest_inprocess(self, *args, stdin=CLOSE_STDIN, **kwargs):
         """Return result of running pytest in-process, providing a similar
         interface to what self.runpytest() provides.
         """
@@ -856,7 +856,18 @@ def runpytest_inprocess(self, *args, **kwargs):
         if syspathinsert:
             self.syspathinsert()
         now = time.time()
-        capture = MultiCapture(Capture=SysCapture)
+        if stdin is self.CLOSE_STDIN:
+            Capture = SysCapture
+        else:
+            if isinstance(stdin, str):
+                import io
+                import functools
+
+                Capture = functools.partial(SysCapture, stdin=io.StringIO(stdin))
+            else:
+                Capture = stdin
+
+        capture = MultiCapture(Capture=Capture)
         capture.start_capturing()
         try:
             try:

From b8a79bf4dca433bb36eefc2231889baa037643ea Mon Sep 17 00:00:00 2001
From: Daniel Hahler <git@thequod.de>
Date: Mon, 21 Oct 2019 04:07:08 +0200
Subject: [PATCH 3/4] use runpytest/stdin with test_pdb_used_in_generate_tests

---
 testing/test_pdb.py | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/testing/test_pdb.py b/testing/test_pdb.py
index 924c2f4af36..4ebdebcb208 100644
--- a/testing/test_pdb.py
+++ b/testing/test_pdb.py
@@ -724,17 +724,21 @@ def test_pdb_used_in_generate_tests(self, testdir):
             """
             import pytest
             def pytest_generate_tests(metafunc):
-                pytest.set_trace()
                 x = 5
+                pytest.set_trace()
+
             def test_foo(a):
                 pass
         """
         )
-        child = testdir.spawn_pytest(str(p1))
-        child.expect("x = 5")
-        child.expect("Pdb")
-        child.sendeof()
-        self.flush(child)
+        result = testdir.runpytest(str(p1), stdin="p 'x=' + str(x)\nq\n")
+        result.stdout.fnmatch_lines(
+            [
+                "*> PDB set_trace (IO-capturing turned off) >*",
+                "'x=5'",
+                "E   _pytest.outcomes.Exit: Quitting debugger",
+            ]
+        )
 
     def test_pdb_collection_failure_is_shown(self, testdir):
         p1 = testdir.makepyfile("xxx")

From 8c01c10e26ac2d05c07aaf6a5084a32685df4719 Mon Sep 17 00:00:00 2001
From: Daniel Hahler <git@thequod.de>
Date: Mon, 21 Oct 2019 04:08:27 +0200
Subject: [PATCH 4/4] Use EchoingInput wrapper

---
 src/_pytest/pytester.py | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/_pytest/pytester.py b/src/_pytest/pytester.py
index 83e0910834e..897242fb483 100644
--- a/src/_pytest/pytester.py
+++ b/src/_pytest/pytester.py
@@ -859,11 +859,19 @@ def runpytest_inprocess(self, *args, stdin=CLOSE_STDIN, **kwargs):
         if stdin is self.CLOSE_STDIN:
             Capture = SysCapture
         else:
+            old_stdin = sys.stdin
             if isinstance(stdin, str):
                 import io
                 import functools
 
-                Capture = functools.partial(SysCapture, stdin=io.StringIO(stdin))
+                class EchoingInput(io.StringIO):
+                    def readline(self, *args, **kwargs):
+                        ret = super().readline(*args, **kwargs)
+                        if ret is not None:
+                            sys.stdout.write(ret)
+                        return ret
+
+                Capture = functools.partial(SysCapture, stdin=EchoingInput(stdin))
             else:
                 Capture = stdin
 
@@ -889,6 +897,9 @@ class reprec:
             sys.stdout.write(out)
             sys.stderr.write(err)
 
+            if stdin is not self.CLOSE_STDIN:
+                sys.stdin = old_stdin
+
         res = RunResult(reprec.ret, out.split("\n"), err.split("\n"), time.time() - now)
         res.reprec = reprec
         return res