add red-herring tests which modify distinct inputs

salsa-2022-tests/tests/hello_world.rs

@@ -83,3 +83,28 @@ fn execute() {
             "final_result(MyInput(Id { value: 1 }))",
         ]"#]]);
 }
+
+/// Create and mutate a distinct input. No re-execution required.
+#[test]
+fn red_herring() {
+    let mut db = Database::default();
+
+    let input = MyInput::new(&mut db, 22);
+    assert_eq!(final_result(&db, input), 22);
+    db.assert_logs(expect![[r#"
+        [
+            "final_result(MyInput(Id { value: 1 }))",
+            "intermediate_result(MyInput(Id { value: 1 }))",
+        ]"#]]);
+
+    // Create a distinct input and mutate it.
+    // This will trigger a new revision in the database
+    // but shouldn't actually invalidate our existing ones.
+    let input2 = MyInput::new(&mut db, 44);
+    input2.set_field(&mut db, 66);
+
+    // Re-run the query on the original input. Nothing re-executes!
+    assert_eq!(final_result(&db, input), 22);
+    db.assert_logs(expect![[r#"
+        []"#]]);
+}

salsa-2022-tests/tests/tracked_fn_read_own_entity.rs

@@ -57,7 +57,7 @@ impl HasLogger for Database {
 }
 
 #[test]
-fn execute() {
+fn one_entity() {
     let mut db = Database::default();
 
     let input = MyInput::new(&mut db, 22);
@@ -85,3 +85,29 @@ fn execute() {
             "final_result(MyInput(Id { value: 1 }))",
         ]"#]]);
 }
+
+/// Create and mutate a distinct input. No re-execution required.
+#[test]
+fn red_herring() {
+    let mut db = Database::default();
+
+    let input = MyInput::new(&mut db, 22);
+    assert_eq!(final_result(&db, input), 22);
+    db.assert_logs(expect![[r#"
+        [
+            "final_result(MyInput(Id { value: 1 }))",
+            "intermediate_result(MyInput(Id { value: 1 }))",
+        ]"#]]);
+
+    // Create a distinct input and mutate it.
+    // This will trigger a new revision in the database
+    // but shouldn't actually invalidate our existing ones.
+    let input2 = MyInput::new(&mut db, 44);
+    input2.set_field(&mut db, 66);
+
+    // Re-run the query on the original input. Nothing re-executes!
+    assert_eq!(final_result(&db, input), 22);
+    db.assert_logs(expect![[r#"
+        [
+        ]"#]]);
+}