[gdb/testsuite] Reimplement gdb.gdb/python-selftest.exp as unittest

The test-case gdb.gdb/python-selftest.exp:
- patches the gdb_python_initialized variable in gdb to 0
- checks that the output of a python command is "Python not initialized"

Reimplement gdb.gdb/python-selftest.exp as unittest, using:
- execute_command_to_string to capture the output
- try/catch to catch the "Python not initialized" exception.

Tested on x86_64-linux.

2 files changed, 46 insertions, 30 deletions

diff --git a/gdb/python/python.c b/gdb/python/python.c
index 6af9c72..5918bb4 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -35,6 +35,7 @@
 #include <ctype.h>
 #include "location.h"
 #include "run-on-main-thread.h"
+#include "gdbsupport/selftest.h"
 
 /* Declared constants and enum for python stack printing.  */
 static const char python_excp_none[] = "none";
@@ -1879,6 +1880,47 @@ do_start_initialization ()
 
 #endif /* HAVE_PYTHON */
 
+#if GDB_SELF_TEST
+namespace selftests {
+
+/* Entry point for python unit tests.  */
+
+static void
+test_python ()
+{
+#define CMD execute_command_to_string ("python print(5)", 0, true);
+
+  std::string output;
+
+  output = CMD;
+  SELF_CHECK (output == "5\n");
+  output.clear ();
+
+  bool saw_exception = false;
+  scoped_restore reset_gdb_python_initialized
+    = make_scoped_restore (&gdb_python_initialized, 0);
+  try
+    {
+      output = CMD;
+    }
+  catch (const gdb_exception &e)
+    {
+      saw_exception = true;
+      SELF_CHECK (e.reason == RETURN_ERROR);
+      SELF_CHECK (e.error == GENERIC_ERROR);
+      SELF_CHECK (*e.message == "Python not initialized");
+    }
+  SELF_CHECK (saw_exception);
+  SELF_CHECK (output.empty ());
+
+#undef CMD
+}
+
+#undef CHECK_OUTPUT
+
+} // namespace selftests
+#endif /* GDB_SELF_TEST */
+
 /* See python.h.  */
 cmd_list_element *python_cmd_element = nullptr;
 
@@ -1977,6 +2019,10 @@ python executable."),
 				show_python_dont_write_bytecode,
 				&user_set_python_list,
 				&user_show_python_list);
+
+#if GDB_SELF_TEST
+  selftests::register_test ("python", selftests::test_python);
+#endif /* GDB_SELF_TEST */
 }
 
 #ifdef HAVE_PYTHON
diff --git a/gdb/testsuite/gdb.gdb/python-selftest.exp b/gdb/testsuite/gdb.gdb/python-selftest.exp
deleted file mode 100644
index 74b2c52..0000000
--- a/gdb/testsuite/gdb.gdb/python-selftest.exp
+++ /dev/null
@@ -1,30 +0,0 @@
-# Copyright 2013-2021 Free Software Foundation, Inc.
-
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-load_lib selftest-support.exp
-load_lib gdb-python.exp
-
-proc selftest_python {} {
-    if {[skip_python_tests]} {
-	return -1
-    }
-
-    gdb_test_no_output "set variable gdb_python_initialized = 0"
-    gdb_test "call catch_command_errors(execute_command, \"python print(5)\", 0, true)" \
-	"Python not initialized.* = 0"
-    return 0
-}
-
-do_self_tests captured_command_loop selftest_python