# HG changeset patch
# Parent  fa4d8276d0fbeb9fd9527ae0538d396ba5c5d249
Issue #13886: Fix input() tests to explicitly run with and without Readline

Previously, the two non-ASCII tests would fail if the Readline module had
been loaded. Now each test is repeated in a subprocess, with and without the
Readline module loaded.

Also changed the non-ASCII encoding test to use properly-encoded UTF-8
without needing error handling. Do not test error handling of Readline
because it does not seem to be well-defined.

diff -r fa4d8276d0fb Lib/test/test_builtin.py
--- a/Lib/test/test_builtin.py	Tue Dec 06 00:24:19 2016 +0200
+++ b/Lib/test/test_builtin.py	Tue Dec 06 03:23:32 2016 +0000
@@ -12,6 +12,7 @@
 import platform
 import random
 import re
+import subprocess
 import sys
 import traceback
 import types
@@ -1556,31 +1557,49 @@
         os.close(fd)
         return lines
 
-    def check_input_tty(self, prompt, terminal_input, stdio_encoding=None):
-        if not sys.stdin.isatty() or not sys.stdout.isatty():
-            self.skipTest("stdin and stdout must be ttys")
-        def child(wpipe):
-            # Check the error handlers are accounted for
-            if stdio_encoding:
-                sys.stdin = io.TextIOWrapper(sys.stdin.detach(),
-                                             encoding=stdio_encoding,
-                                             errors='surrogateescape')
-                sys.stdout = io.TextIOWrapper(sys.stdout.detach(),
-                                              encoding=stdio_encoding,
-                                              errors='replace')
-            print("tty =", sys.stdin.isatty() and sys.stdout.isatty(), file=wpipe)
-            print(ascii(input(prompt)), file=wpipe)
-        lines = self.run_child(child, terminal_input + b"\r\n")
-        # Check we did exercise the GNU readline path
-        self.assertIn(lines[0], {'tty = True', 'tty = False'})
-        if lines[0] != 'tty = True':
-            self.skipTest("standard IO in should have been a tty")
-        input_result = eval(lines[1])   # ascii() -> eval() roundtrip
+    def check_input_tty(self, prompt, terminal_input, stdio_encoding=None, *,
+            readline=True):
+        template = (
+            'import sys, io\n'
+            'if {readline!a}:\n'
+            '    import readline\n'
+            '# Check the error handlers are accounted for\n'
+            'stdio_encoding = {stdio_encoding!a}\n'
+            'if stdio_encoding:\n'
+            '    sys.stdin = io.TextIOWrapper(sys.stdin.detach(),\n'
+            '                                 encoding=stdio_encoding,\n'
+            "                                 errors='surrogateescape')\n"
+            '    sys.stdout = io.TextIOWrapper(sys.stdout.detach(),\n'
+            '                                  encoding=stdio_encoding,\n'
+            "                                  errors='replace')\n"
+            '# Check we exercise the PyOS_Readline() path\n'
+            'if not sys.stdin.isatty() or not sys.stdout.isatty():\n'
+            '    raise AssertionError("standard IO should be a tty")\n'
+            'result = input({prompt!a})\n'
+            'if result != {expected!a}:\n'
+            '    raise AssertionError("unexpected input " + ascii(result))\n'
+        )
         if stdio_encoding:
             expected = terminal_input.decode(stdio_encoding, 'surrogateescape')
         else:
             expected = terminal_input.decode(sys.stdin.encoding)  # what else?
-        self.assertEqual(input_result, expected)
+        tests = [False]
+        if readline:
+            tests.append(True)
+        for readline in tests:
+            with self.subTest(expected=expected, readline=readline):
+                code = template.format(
+                    readline=readline, stdio_encoding=stdio_encoding,
+                    prompt=prompt, expected=expected)
+                cmd = (sys.executable, '-s', '-c', code)
+                [master, slave] = pty.openpty()
+                with os.fdopen(master, 'wb') as writer, \
+                        subprocess.Popen(cmd, stdin=slave, stdout=slave,
+                            stderr=subprocess.DEVNULL) as proc:
+                    os.close(slave)
+                    writer.write(terminal_input + b"\r\n")
+                    writer.flush()
+                self.assertEqual(proc.returncode, 0)
 
     def test_input_tty(self):
         # Test input() functionality when wired to a tty (the code path
@@ -1588,12 +1607,13 @@
         self.check_input_tty("prompt", b"quux")
 
     def test_input_tty_non_ascii(self):
-        # Check stdin/stdout encoding is used when invoking GNU readline
-        self.check_input_tty("prompté", b"quux\xe9", "utf-8")
+        # Check stdin/stdout encoding is used when invoking PyOS_Readline()
+        self.check_input_tty("prompté", "quuxé".encode("utf-8"), "utf-8")
 
     def test_input_tty_non_ascii_unicode_errors(self):
-        # Check stdin/stdout error handler is used when invoking GNU readline
-        self.check_input_tty("prompté", b"quux\xe9", "ascii")
+        # Check stdin/stdout error handler used when invoking PyOS_Readline()
+        # GNU Readline does not seem to handle encoding errors consistently
+        self.check_input_tty("prompté", b"quux\xe9", "ascii", readline=False)
 
     def test_input_no_stdout_fileno(self):
         # Issue #24402: If stdin is the original terminal but stdout.fileno()