[pushed] Add selftest for substitute_path_component

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index a62255fb03..4510a28cd8 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@ 
+2018-03-15  Simon Marchi  <simon.marchi@polymtl.ca>
+
+	* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
+	unittests/utils-selftests.c.
+	* unittests/utils-selftests.c: New file.
+
 2018-03-14  Tom Tromey  <tom@tromey.com>
 
 	PR cli/14977:
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 690653ac04..8121fb025f 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -428,6 +428,7 @@  SUBDIR_UNITTESTS_SRCS = \
 	unittests/scoped_mmap-selftests.c \
 	unittests/scoped_restore-selftests.c \
 	unittests/unpack-selftests.c \
+	unittests/utils-selftests.c \
 	unittests/xml-utils-selftests.c
 
 SUBDIR_UNITTESTS_OBS = $(patsubst %.c,%.o,$(SUBDIR_UNITTESTS_SRCS))
diff --git a/gdb/unittests/utils-selftests.c b/gdb/unittests/utils-selftests.c
new file mode 100644
index 0000000000..b8ce65246e
--- /dev/null
+++ b/gdb/unittests/utils-selftests.c
@@ -0,0 +1,59 @@ 
+/* Unit tests for the utils.c file.
+
+   Copyright (C) 2018 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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/>.  */
+
+#include "defs.h"
+#include "utils.h"
+#include "selftest.h"
+
+namespace selftests {
+namespace utils {
+
+static void
+test_substitute_path_component ()
+{
+  auto test = [] (std::string s, const char *from, const char *to,
+		  const char *expected)
+    {
+      char *temp = xstrdup (s.c_str ());
+      substitute_path_component (&temp, from, to);
+      SELF_CHECK (strcmp (temp, expected) == 0);
+      xfree (temp);
+    };
+
+  test ("/abc/$def/g", "abc", "xyz", "/xyz/$def/g");
+  test ("abc/$def/g", "abc", "xyz", "xyz/$def/g");
+  test ("/abc/$def/g", "$def", "xyz", "/abc/xyz/g");
+  test ("/abc/$def/g", "g", "xyz", "/abc/$def/xyz");
+  test ("/abc/$def/g", "ab", "xyz", "/abc/$def/g");
+  test ("/abc/$def/g", "def", "xyz", "/abc/$def/g");
+  test ("/abc/$def/g", "abc", "abc", "/abc/$def/g");
+  test ("/abc/$def/g", "abc", "", "//$def/g");
+  test ("/abc/$def/g", "abc/$def", "xyz", "/xyz/g");
+  test ("/abc/$def/abc", "abc", "xyz", "/xyz/$def/xyz");
+}
+
+}
+}
+
+void
+_initialize_utils_selftests ()
+{
+  selftests::register_test ("substitute_path_component",
+			    selftests::utils::test_substitute_path_component);
+}