diff options
Diffstat (limited to 'lib/testresources/__init__.py')
| -rw-r--r-- | lib/testresources/__init__.py | 76 |
1 files changed, 64 insertions, 12 deletions
diff --git a/lib/testresources/__init__.py b/lib/testresources/__init__.py index 217280f..bda974a 100644 --- a/lib/testresources/__init__.py +++ b/lib/testresources/__init__.py @@ -546,6 +546,7 @@ class TestResourceManager(object): :param dependency_resources: A dict mapping name -> resource instance for the resources specified as dependencies. + :return: The made resource. """ raise NotImplementedError( "Override make to construct resources.") @@ -568,24 +569,71 @@ class TestResourceManager(object): return result def reset(self, old_resource, result=None): - """Overridable method to return a clean version of old_resource. + """Return a clean version of old_resource. By default, the resource will be cleaned then remade if it had - previously been `dirtied`. - - This function needs to take the dependent resource stack into - consideration as _make_all and _clean_all do. - - :return: The new resource. + previously been `dirtied` by the helper self._reset() - which is the + extension point folk should override to customise reset behaviour. + + This function takes the dependent resource stack into consideration as + _make_all and _clean_all do. The inconsistent naming is because reset + is part of the public interface, but _make_all and _clean_all is not. + + Note that if a resource A holds a lock or other blocking thing on + a dependency D, reset will result in this call sequence over a + getResource(), dirty(), getResource(), finishedWith(), finishedWith() + sequence: + B.make(), A.make(), B.reset(), A.reset(), A.clean(), B.clean() + Thus it is important that B.reset not assume that A has been cleaned or + reset before B is reset: it should arrange to reference count, lazy + cleanup or forcibly reset resource in some fashion. + + As an example, consider that B is a database with sample data, and + A is an application server serving content from it. B._reset() should + disconnect all database clients, reset the state of the database, and + A._reset() should tell the application server to dump any internal + caches it might have. + + In principle we might make a richer API to allow before-and-after + reset actions, but so far that hasn't been needed. + + :return: The possibly new resource. :param result: An optional TestResult to report resource changes to. """ - if self.isDirty(): - self._clean_all(old_resource, result) - resource = self._make_all(result) - else: - resource = old_resource + # Core logic: + # - if neither we nor any parent is dirty, do nothing. + # otherwise + # - emit a signal to the test result + # - reset all dependencies all, getting new attributes. + # - call self._reset(old_resource, dependency_attributes) + # [the default implementation does a clean + make] + if not self.isDirty(): + return old_resource + self._call_result_method_if_exists(result, "startResetResource", self) + dependency_resources = {} + for name, mgr in self.resources: + dependency_resources[name] = mgr.reset( + getattr(old_resource, name), result) + resource = self._reset(old_resource, dependency_resources) + for name, value in dependency_resources.items(): + setattr(resource, name, value) + self._call_result_method_if_exists(result, "stopResetResource", self) return resource + def _reset(self, resource, dependency_resources): + """Override this to reset resources other than via clean+make. + + This method should reset the self._dirty flag (assuming the manager can + ever be clean) and return either the old resource cleaned or a fresh + one. + + :param resource: The resource to reset. + :param dependency_resources: A dict mapping name -> resource instance + for the resources specified as dependencies. + """ + self.clean(resource) + return self.make(dependency_resources) + def _setResource(self, new_resource): """Set the current resource to a new value.""" self._currentResource = new_resource @@ -671,6 +719,10 @@ class FixtureResource(TestResourceManager): self.fixture.setUp() return self.fixture + def _reset(self, resource, dependency_resources): + self.fixture.reset() + return self.fixture + def isDirty(self): return True |