preparing test_user_mode, need to generalize stuff as usual

example_properties.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+
+class ExampleProperties:
+    '''
+    Encodes properties of userland and baremetal examples.
+    For directories, it applies to all files under the directory.
+    Used to determine how to build and test the examples.
+    '''
+    def __init__(
+        exit_status=0,
+        interactive=False,
+        more_than_1s=False,
+    ):
+        self.exit_status = exit_status
+        self.interactive = interactive
+        self.more_than_1s = more_than_1s
+
+    def should_be_tested(self):
+        return \
+            not self.interactive and \
+            not self.more_than_1s
+
+executable_properties = {
+    'userland/arch/x86_64/c/ring0.c': ExecutableProperties(exits_nonzero=True),
+}