add ParentNotFound error, if parent can't be fetched

lib/diaspora_federation/entities/relayable.rb

@@ -216,6 +216,7 @@ module DiasporaFederation
             # fetch and receive parent from remote, if not available locally
             Federation::Fetcher.fetch_public(data[:author], type, guid)
             data[:parent] = DiasporaFederation.callbacks.trigger(:fetch_related_entity, type, guid)
+            raise ParentNotFound unless data[:parent]
           end
         end
       end
@@ -231,6 +232,10 @@ module DiasporaFederation
       # Raised, if verify_signatures fails to verify signatures (signatures are wrong)
       class SignatureVerificationFailed < RuntimeError
       end
+
+      # Raised, if parent was not found and can't be fetched
+      class ParentNotFound < RuntimeError
+      end
     end
   end
 end

spec/lib/diaspora_federation/entities/relayable_spec.rb

@@ -297,8 +297,6 @@ XML
 
     context "fetch parent" do
       before do
-        expect_callback(:fetch_public_key, author).and_return(author_pkey.public_key)
-        expect_callback(:fetch_public_key, remote_parent.author).and_return(parent_pkey.public_key)
         expect_callback(:fetch_private_key, author).and_return(author_pkey)
         expect_callback(:fetch_private_key, remote_parent.author).and_return(parent_pkey)
       end
@@ -306,6 +304,9 @@ XML
       let(:xml) { SomeRelayable.new(hash).to_xml }
 
       it "fetches the parent from the backend" do
+        expect_callback(:fetch_public_key, author).and_return(author_pkey.public_key)
+        expect_callback(:fetch_public_key, remote_parent.author).and_return(parent_pkey.public_key)
+
         expect_callback(:fetch_related_entity, "Parent", parent_guid).and_return(remote_parent)
         expect(Federation::Fetcher).not_to receive(:fetch_public)
 
@@ -315,6 +316,9 @@ XML
       end
 
       it "fetches the parent from remote if not found on backend" do
+        expect_callback(:fetch_public_key, author).and_return(author_pkey.public_key)
+        expect_callback(:fetch_public_key, remote_parent.author).and_return(parent_pkey.public_key)
+
         expect_callback(:fetch_related_entity, "Parent", parent_guid).and_return(nil, remote_parent)
         expect(Federation::Fetcher).to receive(:fetch_public).with(author, "Parent", parent_guid)
 
@@ -322,6 +326,15 @@ XML
 
         expect(entity.parent).to eq(remote_parent)
       end
+
+      it "raises if the parent can't be fetched from remote" do
+        expect_callback(:fetch_related_entity, "Parent", parent_guid).exactly(2).times.and_return(nil)
+        expect(Federation::Fetcher).to receive(:fetch_public).with(author, "Parent", parent_guid)
+
+        expect {
+          SomeRelayable.from_xml(xml)
+        }.to raise_error DiasporaFederation::Entities::Relayable::ParentNotFound
+      end
     end
 
     describe "#sender_valid?" do