testing: add a 'continuous' profile

testing: add a 'continuous' profile

This gives a good way of letting Hypothesis run until it
finds an error, save that error, and be restarted without it
picking up on the old bug. This lets you run long-running
Hypothesis processes and then perform a manual deduplication
task on the bugs found at the end.

It's not an entirely satisfying way of using this, but anything
much better would require extensive changes to Hypothesis itself.

--- a/tests/test-verify-repo-operations.py	Wed Feb 24 13:11:30 2016 +0000
+++ b/tests/test-verify-repo-operations.py	Wed Feb 24 13:20:06 2016 +0000
@@ -41,6 +41,7 @@
     rule, RuleBasedStateMachine, Bundle, precondition)
 from hypothesis import settings, note, strategies as st
 from hypothesis.configuration import set_hypothesis_home_dir
+from hypothesis.database import ExampleDatabase
 
 testdir = os.path.abspath(os.environ["TESTDIR"])
 
@@ -530,6 +531,23 @@
         with acceptableerrors("no shelved changes to apply"):
             self.hg("unshelve")
 
+class writeonlydatabase(ExampleDatabase):
+    def __init__(self, underlying):
+        super(ExampleDatabase, self).__init__()
+        self.underlying = underlying
+
+    def fetch(self, key):
+        return ()
+
+    def save(self, key, value):
+        self.underlying.save(key, value)
+
+    def delete(self, key, value):
+        self.underlying.delete(key, value)
+
+    def close(self):
+        self.underlying.close()
+
 settings.register_profile(
     'default',  settings(
         timeout=300,
@@ -548,6 +566,16 @@
     )
 )
 
+settings.register_profile(
+    'continuous', settings(
+        timeout=-1,
+        stateful_step_count=1000,
+        max_examples=10 ** 8,
+        max_iterations=10 ** 8,
+        database=writeonlydatabase(settings.default.database)
+    )
+)
+
 settings.load_profile(os.getenv('HYPOTHESIS_PROFILE', 'default'))
 
 verifyingtest = verifyingstatemachine.TestCase