Check behaviour in case of exists key or certificate.

slapos/libnetworkcachetests.py

@@ -776,12 +776,14 @@ class GenerateSignatureScriptTest(unittest.TestCase):
     self.certificate = os.path.join(tempfile.gettempdir(), tempfile.gettempprefix()
       + str(random.random()))
     self.common_name = str(random.random())
+    self.key_exist = tempfile.NamedTemporaryFile(delete=False).name
+    self.certificate_exist = tempfile.NamedTemporaryFile(delete=False).name
 
   def tearDown(self):
-    if os.path.exists(self.key):
-      os.unlink(self.key)
-    if os.path.exists(self.certificate):
-      os.unlink(self.certificate)
+    for f in [self.key, self.certificate, self.key_exist,
+      self.certificate_exist]:
+      if os.path.lexists(f):
+        os.unlink(f)
 
   def test_generate_certificate(self):
     slapos.signature.generateCertificate(self.certificate, self.key,
@@ -789,3 +791,12 @@ class GenerateSignatureScriptTest(unittest.TestCase):
     result = subprocess.check_output(['openssl', 'x509', '-noout', '-subject',
       '-in', self.certificate])
     self.assertEqual('subject= /CN=%s' % self.common_name, result.strip())
+
+  def test_generate_key_exists(self):
+    self.assertRaises(ValueError, slapos.signature.generateCertificate,
+      self.certificate, self.key_exist, self.common_name)
+
+  def test_generate_cert_exists(self):
+    self.assertRaises(ValueError, slapos.signature.generateCertificate,
+      self.certificate_exist, self.key, self.common_name)
+