Factor out the discover logic to the test module

This avoids duplication in sugar and sugar-toolkit-gtk3
makefiles.

Makefile.am

@@ -1,9 +1,6 @@
 ACLOCAL_AMFLAGS = -I m4
 DISTCHECK_CONFIGURE_FLAGS = --enable-introspection
 
-TESTS_TMPDIR=$(abs_builddir)/tests-tmp
-TESTS_PYTHONPATH=$(abs_srcdir)/src:$(PYTHONPATH)
-
 DISTCLEANFILES =		\
 	intltool-extract	\
 	intltool-merge		\
@@ -21,10 +18,4 @@ check: test
 	pep8 $(top_srcdir)
 
 test:
-	mkdir -p $(TESTS_TMPDIR)
+	python -m sugar3.test.discover $(top_srcdir)/tests
-	cd $(top_srcdir)/tests; \
-	TMPDIR=$(TESTS_TMPDIR) PYTHONPATH=$(TESTS_PYTHONPATH) \
-	python -m unittest discover; \
-	status=$$?; \
-	rm -rf $(TESTS_TMPDIR); \
-	exit $$status

src/sugar3/test/Makefile.am

@@ -1,5 +1,6 @@
 sugardir = $(pythondir)/sugar3/test
 sugar_PYTHON = \
 	__init__.py \
+    discover.py \
 	uitree.py \
 	unittest.py

src/sugar3/test/discover.py

@@ -0,0 +1,51 @@
+# Copyright (C) 2013, Daniel Narvaez
+#
+# 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 2 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, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+"""
+UNSTABLE.
+"""
+
+from __future__ import absolute_import
+
+import argparse
+import sys
+import os
+import tempfile
+import shutil
+import unittest
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Discover unit tests.")
+    parser.add_argument("tests_dir", help="Base tests directory")
+    args = parser.parse_args()
+
+    temp_dir = tempfile.mkdtemp()
+
+    os.chdir(args.tests_dir)
+    os.environ["TMPDIR"] = temp_dir
+
+    try:
+        test = unittest.defaultTestLoader.discover(".")
+        result = unittest.TextTestRunner().run(test)
+        if not result.wasSuccessful():
+            sys.exit(1)
+    finally:
+        shutil.rmtree(temp_dir)
+
+
+if __name__ == "__main__":
+    main()