'Sets an environment used for nested quotas tests.
Create a project hierarchy such as follows:
|     A    G   E  |
|   B   C       F |
| D               |'

def _create_project_hierarchy(self):

    super(QuotaSetControllerValidateNestedQuotaSetup, self)._create_project_hierarchy()
    self.E = self.FakeProject(id=uuid.uuid4().hex, parent_id=None)
    self.F = self.FakeProject(id=uuid.uuid4().hex, parent_id=self.E.id)
    self.G = self.FakeProject(id=uuid.uuid4().hex, parent_id=None)
    self.E.subtree = {self.F.id: self.F.subtree}
    self.project_by_id.update({self.E.id: self.E, self.F.id: self.F, self.G.id: self.G})
