avocado.core.exceptions: Update fail_on_error and rename to fail_on

This patch renames the fail_on_error decorator to fail_on and adds
support to supply list of exceptions. This way the decorator can be used
not only to make tests fail on generic exceptions but also to specify
parts of code with expected failures of given type.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

avocado/__init__.py

@@ -13,10 +13,10 @@
 # Author: Lucas Meneghel Rodrigues <lmr@redhat.com>
 
 
-__all__ = ['main', 'Test', 'VERSION', 'fail_on_error']
+__all__ = ['main', 'Test', 'VERSION', 'fail_on']
 
 
 from avocado.core.job import main
 from avocado.core.test import Test
 from avocado.core.version import VERSION
-from avocado.core.exceptions import fail_on_error
+from avocado.core.exceptions import fail_on

avocado/core/exceptions.py

@@ -15,29 +15,45 @@
 """
 Exception classes, useful for tests, and other parts of the framework code.
 """
-
-
-def fail_on_error(fn):
-    """
-    Apply to any test you want to FAIL upon any exception raised.
-
-    Normally only TestFail called explicitly will mark an avocado test with the
-    FAIL state, but this decorator is provided as a convenience for people
-    that need a more relaxed behavior.
-
-    :param fn: Function that will be decorated
-    """
-    def new_fn(*args, **kwargs):
-        try:
-            return fn(*args, **kwargs)
-        except TestBaseException:
-            raise
-        except Exception, e:
-            raise TestFail(str(e))
-    new_fn.__name__ = fn.__name__
-    new_fn.__doc__ = fn.__doc__
-    new_fn.__dict__.update(fn.__dict__)
-    return new_fn
+from functools import wraps
+import types
+
+
+def fail_on(exceptions=None):
+    """
+    Fail the test when decorated function produces exception of the specified
+    type.
+
+    (For example, our method may raise IndexError on tested software failure.
+    We can either try/catch it or use this decorator instead)
+
+    :param exceptions: Tuple or single exception to be assumed as
+                       test fail [Exception]
+    :note: self.error and self.skip behavior remains intact
+    :note: To allow simple usage param "exceptions" must not be callable
+    """
+    func = False
+    if exceptions is None:
+        exceptions = Exception
+    elif isinstance(exceptions, types.FunctionType):     # @fail_on without ()
+        func = exceptions
+        exceptions = Exception
+
+    def decorate(func):
+        """ Decorator """
+        @wraps(func)
+        def wrap(*args, **kwargs):
+            """ Function wrapper """
+            try:
+                return func(*args, **kwargs)
+            except TestBaseException:
+                raise
+            except exceptions, details:
+                raise TestFail(str(details))
+        return wrap
+    if func:
+        return decorate(func)
+    return decorate
 
 
 class JobBaseException(Exception):

examples/tests/fail_on_error.py → examples/tests/fail_on_exception.py

@@ -3,13 +3,14 @@
 import avocado
 
 
-class FailOnError(avocado.Test):
+class FailOnException(avocado.Test):
 
     """
-    Test illustrating the behavior of the fail_on_error decorator.
+    Test illustrating the behavior of the fail_on decorator.
     """
 
-    @avocado.fail_on_error
+    # @avocado.fail_on(ValueError) also possible
+    @avocado.fail_on
     def test(self):
         """
         This should end with FAIL.

selftests/all/functional/avocado/basic_tests.py

@@ -126,10 +126,10 @@ class RunnerOperationTest(unittest.TestCase):
                                                                 result))
         self.assertIn('"status": "ERROR"', result.stdout)
 
-    def test_fail_on_error(self):
+    def test_fail_on_exception(self):
         os.chdir(basedir)
         cmd_line = ("./scripts/avocado run --sysinfo=off --job-results-dir %s "
-                    "--json - fail_on_error" % self.tmpdir)
+                    "--json - fail_on_exception" % self.tmpdir)
         result = process.run(cmd_line, ignore_status=True)
         expected_rc = 1
         self.assertEqual(result.exit_status, expected_rc,