tests/avocado: Extract QemuBaseTest from Test

The Avocado Test::fetch_asset() is handy to download artifacts
before running tests. The current class is named Test but only
tests system emulation. As we want to test user emulation,
refactor the common code as QemuBaseTest.

Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20211105143416.148332-2-f4bug@amsat.org>

tests/avocado/avocado_qemu/__init__.py

@@ -169,7 +169,7 @@ def exec_command_and_wait_for_pattern(test, command,
     """
     _console_interaction(test, success_message, failure_message, command + '\r')
 
-class Test(avocado.Test):
+class QemuBaseTest(avocado.Test):
     def _get_unique_tag_val(self, tag_name):
         """
         Gets a tag value, if unique for a key
@@ -179,6 +179,46 @@ class Test(avocado.Test):
             return vals.pop()
         return None
 
+    def setUp(self):
+        self.arch = self.params.get('arch',
+                                    default=self._get_unique_tag_val('arch'))
+
+        self.cpu = self.params.get('cpu',
+                                   default=self._get_unique_tag_val('cpu'))
+
+        default_qemu_bin = pick_default_qemu_bin(arch=self.arch)
+        self.qemu_bin = self.params.get('qemu_bin',
+                                        default=default_qemu_bin)
+        if self.qemu_bin is None:
+            self.cancel("No QEMU binary defined or found in the build tree")
+
+    def fetch_asset(self, name,
+                    asset_hash=None, algorithm=None,
+                    locations=None, expire=None,
+                    find_only=False, cancel_on_missing=True):
+        return super().fetch_asset(name,
+                        asset_hash=asset_hash,
+                        algorithm=algorithm,
+                        locations=locations,
+                        expire=expire,
+                        find_only=find_only,
+                        cancel_on_missing=cancel_on_missing)
+
+
+class Test(QemuBaseTest):
+    """Facilitates system emulation tests.
+
+    TODO: Rename this class as `QemuSystemTest`.
+    """
+
+    def setUp(self):
+        self._vms = {}
+
+        super().setUp()
+
+        self.machine = self.params.get('machine',
+                                       default=self._get_unique_tag_val('machine'))
+
     def require_accelerator(self, accelerator):
         """
         Requires an accelerator to be available for the test to continue
@@ -201,24 +241,6 @@ class Test(avocado.Test):
             self.cancel("%s accelerator does not seem to be "
                         "available" % accelerator)
 
-    def setUp(self):
-        self._vms = {}
-
-        self.arch = self.params.get('arch',
-                                    default=self._get_unique_tag_val('arch'))
-
-        self.cpu = self.params.get('cpu',
-                                   default=self._get_unique_tag_val('cpu'))
-
-        self.machine = self.params.get('machine',
-                                       default=self._get_unique_tag_val('machine'))
-
-        default_qemu_bin = pick_default_qemu_bin(arch=self.arch)
-        self.qemu_bin = self.params.get('qemu_bin',
-                                        default=default_qemu_bin)
-        if self.qemu_bin is None:
-            self.cancel("No QEMU binary defined or found in the build tree")
-
     def _new_vm(self, name, *args):
         self._sd = tempfile.TemporaryDirectory(prefix="avo_qemu_sock_")
         vm = QEMUMachine(self.qemu_bin, base_temp_dir=self.workdir,
@@ -272,18 +294,6 @@ class Test(avocado.Test):
         self._sd = None
         super().tearDown()
 
-    def fetch_asset(self, name,
-                    asset_hash=None, algorithm=None,
-                    locations=None, expire=None,
-                    find_only=False, cancel_on_missing=True):
-        return super().fetch_asset(name,
-                        asset_hash=asset_hash,
-                        algorithm=algorithm,
-                        locations=locations,
-                        expire=expire,
-                        find_only=find_only,
-                        cancel_on_missing=cancel_on_missing)
-
 
 class LinuxSSHMixIn:
     """Contains utility methods for interacting with a guest via SSH."""