diff --git a/avocado/core/test.py b/avocado/core/test.py
index 2e490a6f3f1002e918fb62e9f53ff6d79ee2df9b..38c2e78c8c5807d999a44122a7825f139398a7d8 100644
--- a/avocado/core/test.py
+++ b/avocado/core/test.py
@@ -153,7 +153,8 @@ class TestID(object):
         For Test ID "001-mytest;foo", examples of shortened file
         system versions include "001-mytest;f" or "001-myte;foo".
 
-        :raises: AssertionError
+        :raises: RuntimeError if the test ID cannot be converted to a
+                 filesystem representation.
         """
         test_id = str(self)
         test_id_fs = astring.string_to_safe_path(test_id)
@@ -166,9 +167,9 @@ class TestID(object):
         elif len(self.str_uid) <= len(test_id_fs):   # full uid
             return astring.string_to_safe_path(self.str_uid + self.str_variant)
         else:       # not even uid could be stored in fs
-            raise AssertionError('Test uid is too long to be stored on the '
-                                 'filesystem: "%s"\nFull Test ID: "%s"'
-                                 % (self.str_uid, str(self)))
+            raise RuntimeError('Test ID is too long to be stored on the '
+                               'filesystem: "%s"\nFull Test ID: "%s"'
+                               % (self.str_uid, str(self)))
 
 
 class TestData(object):
@@ -570,9 +571,10 @@ class Test(unittest.TestCase, TestData):
         """
         Override the runner_queue
         """
-        self.assertTrue(self.__runner_queue is None, "Overriding of runner_"
-                        "queue multiple times is not allowed -> old=%s new=%s"
-                        % (self.__runner_queue, runner_queue))
+        if self.__runner_queue is not None:
+            raise RuntimeError("Overriding of runner_queue multiple "
+                               "times is not allowed -> old=%s new=%s"
+                               % (self.__runner_queue, runner_queue))
         self.__runner_queue = runner_queue
 
     @property
@@ -1206,7 +1208,8 @@ class ExternalRunnerTest(SimpleTest):
                  external_runner=None, external_runner_argument=None):
         if external_runner_argument is None:
             external_runner_argument = name.name
-        self.assertIsNotNone(external_runner, "External runner test requires "
+        if external_runner is None:
+            raise ValueError("External runner test requires a valid "
                              "external_runner parameter, got None instead.")
         self.external_runner = external_runner
         super(ExternalRunnerTest, self).__init__(name, params, base_logdir,
diff --git a/selftests/unit/test_test.py b/selftests/unit/test_test.py
index b801973d93ec42f67b8bd482a2e68db39119423a..ad6b5492c116a2f200a51fcfd04621b4b56bf260 100644
--- a/selftests/unit/test_test.py
+++ b/selftests/unit/test_test.py
@@ -90,7 +90,7 @@ class TestClassTestUnit(unittest.TestCase):
         tst = check("a" * 255, "whatever", {"variant_id": "whatever-else"},
                     "a" * 255)
         # Impossible to store (uid does not fit
-        self.assertRaises(AssertionError, check, "a" * 256, "whatever",
+        self.assertRaises(RuntimeError, check, "a" * 256, "whatever",
                           {"variant_id": "else"}, None)
 
         self.assertEqual(os.path.basename(tst.workdir),
@@ -347,7 +347,7 @@ class TestID(unittest.TestCase):
         raised.
         """
         test_id = test.TestID(1, 'test', no_digits=256)
-        self.assertRaises(AssertionError, lambda: test_id.str_filesystem)
+        self.assertRaises(RuntimeError, lambda: test_id.str_filesystem)
 
     def test_uid_large_name(self):
         """