avocado: Simplify setting test default values

Instead of using self.params.set_default() manually for
each default value, allow test writers to set a
default_params attribute with default params, and
set them at test class init time. This way we keep
things even shorter, while allowing avocado tests
to be used stand alone.
Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

avocado/test.py

@@ -39,6 +39,7 @@ class Test(unittest.TestCase):
     You'll inherit from this to write your own tests. Tipically you'll want
     to implement setup(), action() and cleanup() methods on your own tests.
     """
+    default_params = {}
 
     def __init__(self, methodName='runTest', name=None, params=None,
                  base_logdir=None, tag=None, job=None):
@@ -97,13 +98,26 @@ class Test(unittest.TestCase):
 
         self.log.info('START %s', self.tagged_name)
         self.log.debug('')
-        self.log.debug('Test parameters:')
+        self.log.debug('Test instance parameters:')
+
+        # Set the helper set_default to the params object
         setattr(self.params, 'set_default', self._set_default)
+
+        # Apply what comes from the params dict
         for key in sorted(self.params.keys()):
             self.log.debug('    %s = %s', key, self.params.get(key))
             setattr(self.params, key, self.params.get(key))
         self.log.debug('')
 
+        # Apply what comes from the default_params dict
+        self.log.debug('Default parameters:')
+        for key in sorted(self.default_params.keys()):
+            self.log.debug('    %s = %s', key, self.default_params.get(key))
+            self.params.set_default(key, self.default_params[key])
+        self.log.debug('')
+        self.log.debug('Test instance params override defaults whenever available')
+        self.log.debug('')
+
         self.debugdir = None
         self.resultsdir = None
         self.status = None

tests/sleeptest/sleeptest.py

@@ -26,12 +26,7 @@ class sleeptest(test.Test):
     """
     Example test for avocado.
     """
-
-    def setup(self):
-        """
-        If no config was provided, give self.params.sleep_length a default.
-        """
-        self.params.set_default('sleep_length', 1.0)
+    default_params = {'sleep_length': 1.0}
 
     def action(self):
         """

tests/synctest/synctest.py

@@ -14,7 +14,6 @@
 # Copyright: Red Hat Inc. 2013-2014
 # Author: Lucas Meneghel Rodrigues <lmr@redhat.com>
 
-
 import os
 
 from avocado import test
@@ -29,16 +28,14 @@ class synctest(test.Test):
     """
     Execute the synctest test suite.
     """
+    default_params = {'sync_tarball': 'synctest.tar.bz2',
+                      'sync_length': 100,
+                      'sync_loop': 10}
 
     def setup(self):
         """
-        Set default params and build the synctest suite.
+        Build the synctest suite.
         """
-        # Set all params with default values
-        self.params.set_default('sync_tarball', 'synctest.tar.bz2')
-        self.params.set_default('sync_length', 100)
-        self.params.set_default('sync_loop', 10)
-        # Build the synctest suite
         self.cwd = os.getcwd()
         tarball_path = self.get_deps_path(self.params.sync_tarball)
         archive.extract(tarball_path, self.srcdir)