selftest: do not hardcode /tmp/sdk

This races if there are several copies of the test running at the same
time.

[YOCTO #14438]

(From OE-Core rev: deab11848036941771f2b3dc5cdaee83395280b5)

(From OE-Core rev: ea707e8726cd7012d101d02e69503b7c98bdaf3e)

Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/selftest/cases/runtime_test.py

@@ -14,11 +14,6 @@ from oeqa.core.decorator.data import skipIfNotQemu
 
 class TestExport(OESelftestTestCase):
 
-    @classmethod
-    def tearDownClass(cls):
-        runCmd("rm -rf /tmp/sdk")
-        super(TestExport, cls).tearDownClass()
-
     def test_testexport_basic(self):
         """
         Summary: Check basic testexport functionality with only ping test enabled.
@@ -95,19 +90,20 @@ class TestExport(OESelftestTestCase):
         msg = "Couldn't find SDK tarball: %s" % tarball_path
         self.assertEqual(os.path.isfile(tarball_path), True, msg)
 
-        # Extract SDK and run tar from SDK
-        result = runCmd("%s -y -d /tmp/sdk" % tarball_path)
-        self.assertEqual(0, result.status, "Couldn't extract SDK")
+        with tempfile.TemporaryDirectory() as tmpdirname:
+            # Extract SDK and run tar from SDK
+            result = runCmd("%s -y -d %s" % (tarball_path, tmpdirname))
+            self.assertEqual(0, result.status, "Couldn't extract SDK")
 
-        env_script = result.output.split()[-1]
-        result = runCmd(". %s; which tar" % env_script, shell=True)
-        self.assertEqual(0, result.status, "Couldn't setup SDK environment")
-        is_sdk_tar = True if "/tmp/sdk" in result.output else False
-        self.assertTrue(is_sdk_tar, "Couldn't setup SDK environment")
+            env_script = result.output.split()[-1]
+            result = runCmd(". %s; which tar" % env_script, shell=True)
+            self.assertEqual(0, result.status, "Couldn't setup SDK environment")
+            is_sdk_tar = True if tmpdirname in result.output else False
+            self.assertTrue(is_sdk_tar, "Couldn't setup SDK environment")
 
-        tar_sdk = result.output
-        result = runCmd("%s --version" % tar_sdk)
-        self.assertEqual(0, result.status, "Couldn't run tar from SDK")
+            tar_sdk = result.output
+            result = runCmd("%s --version" % tar_sdk)
+            self.assertEqual(0, result.status, "Couldn't run tar from SDK")
 
 
 class TestImage(OESelftestTestCase):