tests: Improve tests and comments to address review

graph/src/components/store/mod.rs

@@ -129,6 +129,11 @@ pub struct EntityKey {
     /// ID of the individual entity.
     pub entity_id: Word,
 
+    /// This is the causality region of the data source that created the entity.
+    ///
+    /// In the case of an entity lookup, this is the causality region of the data source that is
+    /// doing the lookup. So if the entity exists but was created on a different causality region,
+    /// the lookup will return empty.
     pub causality_region: CausalityRegion,
 }
 

graph/src/data_source/causality_region.rs

@@ -51,12 +51,11 @@ impl CausalityRegion {
     }
 
     pub fn from_entity(entity: &Entity) -> Self {
-        CausalityRegion(
-            entity
-                .get("causality_region")
-                .and_then(|v| v.as_int())
-                .unwrap_or(0),
-        )
+        entity
+            .get("causality_region")
+            .and_then(|v| v.as_int())
+            .map(CausalityRegion)
+            .unwrap_or(CausalityRegion::ONCHAIN)
     }
 }
 

graph/src/data_source/tests.rs

@@ -1,6 +1,11 @@
 use cid::Cid;
 
-use crate::{components::subgraph::Entity, ipfs_client::CidFile, prelude::Link};
+use crate::{
+    blockchain::mock::{MockBlockchain, MockDataSource},
+    components::subgraph::Entity,
+    ipfs_client::CidFile,
+    prelude::Link,
+};
 
 use super::{
     offchain::{Mapping, Source},
@@ -45,6 +50,21 @@ fn offchain_mark_processed_error() {
     x.mark_processed_at(-1)
 }
 
+#[test]
+fn data_source_helpers() {
+    let offchain = new_datasource();
+    let offchain_ds = DataSource::<MockBlockchain>::Offchain(offchain.clone());
+    assert!(offchain_ds.causality_region() == offchain.causality_region);
+    assert!(offchain_ds
+        .as_offchain()
+        .unwrap()
+        .is_duplicate_of(&offchain));
+
+    let onchain = DataSource::<MockBlockchain>::Onchain(MockDataSource);
+    assert!(onchain.causality_region() == CausalityRegion::ONCHAIN);
+    assert!(onchain.as_offchain().is_none());
+}
+
 fn new_datasource() -> offchain::DataSource {
     offchain::DataSource::new(
         "theKind".into(),

store/postgres/src/deployment_store.rs

@@ -1053,8 +1053,8 @@ impl DeploymentStore {
         layout.find(&conn, &key, block)
     }
 
-    /// Retrieve all the entities matching `ids_for_type` from the
-    /// deployment `site`. Only consider entities as of the given `block`
+    /// Retrieve all the entities matching `ids_for_type`, both the type and causality region, from
+    /// the deployment `site`. Only consider entities as of the given `block`
     pub(crate) fn get_many(
         &self,
         site: Arc<Site>,

store/postgres/src/relational.rs

@@ -502,6 +502,7 @@ impl Layout {
             .transpose()
     }
 
+    // An optimization when looking up multiple entities, it will generate a single sql query using `UNION ALL`.
     pub fn find_many(
         &self,
         conn: &PgConnection,
@@ -1229,7 +1230,7 @@ pub struct Table {
     pub(crate) immutable: bool,
 
     /// Whether this table has an explicit `causality_region` column. If `false`, then the column is
-    /// not present and the causality region for all rows is implicitly `0`.
+    /// not present and the causality region for all rows is implicitly `0` (equivalent to CasualityRegion::ONCHAIN).
     pub(crate) has_causality_region: bool,
 }
 

store/postgres/tests/relational_bytes.rs

@@ -253,6 +253,7 @@ fn find() {
             .expect("Failed to read Thing[deadbeef]")
             .unwrap();
         assert_entity_eq!(scrub(&*BEEF_ENTITY), entity);
+        assert!(CausalityRegion::from_entity(&entity) == CausalityRegion::ONCHAIN);
 
         // Find non-existing entity
         let entity = layout

tests/integration-tests/file-data-sources/src/mapping.ts

@@ -17,6 +17,9 @@ export function handleBlock(block: ethereum.Block): void {
   }
 
   if (block.number == BigInt.fromI32(1)) {
+    let entity = IpfsFile.load("onchain")!
+    assert(entity.content == "onchain")
+
     // The test assumes file data sources are processed in the block in which they are created.
     // So the ds created at block 0 will have been processed.
     //
@@ -71,6 +74,10 @@ export function handleFile(data: Bytes): void {
   let entity = new IpfsFile(dataSource.stringParam())
   entity.content = data.toString()
   entity.save()
+
+  // Test that an offchain data source can load its own entities
+  let loaded_entity = IpfsFile.load(dataSource.stringParam())!
+  assert(loaded_entity.content == entity.content)
 }
 
 export function handleFile1(data: Bytes): void {

tests/tests/runner.rs

@@ -213,7 +213,7 @@ async fn file_data_sources() {
     let stop_block = test_ptr(5);
     let err = ctx.start_and_sync_to_error(stop_block.clone()).await;
     let message = "entity type `IpfsFile1` is not on the 'entities' list for data source `File2`. \
-                   Hint: Add `IpfsFile1` to the 'entities' list, which currently is: `IpfsFile`.\twasm backtrace:\t    0: 0x35a8 - <unknown>!src/mapping/handleFile1\t in handler `handleFile1` at block #5 ()".to_string();
+                   Hint: Add `IpfsFile1` to the 'entities' list, which currently is: `IpfsFile`.\twasm backtrace:\t    0: 0x365d - <unknown>!src/mapping/handleFile1\t in handler `handleFile1` at block #5 ()".to_string();
     let expected_err = SubgraphError {
         subgraph_id: ctx.deployment.hash.clone(),
         message,