added test for black snapshot and evalutor error

flipt-engine-ffi/src/evaluator/mod.rs

@@ -126,3 +126,38 @@ where
         batch_evaluation(&self.store, &self.namespace, requests)
     }
 }
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use fliptevaluation::models::source;
+    use fliptevaluation::parser;
+    use mockall::predicate::*;
+    use mockall::*;
+
+    mock! {
+        pub Parser{}
+        impl parser::Parser for Parser {
+            fn parse(&self, namespace: &str) -> Result<source::Document, Error>;
+        }
+    }
+
+    #[test]
+    fn test_batch_with_error() {
+        let mut parser = MockParser::new();
+        parser
+            .expect_parse()
+            .returning(|_| Err(Error::Server("can't connect".to_owned())));
+        let evaluator =
+            Evaluator::new_snapshot_evaluator("namespace", parser).expect("expect valid evaluator");
+        let requests = vec![];
+        let response = evaluator.batch(requests);
+        match response {
+            Err(err) => {
+                assert_eq!("server error: can't connect", err.to_string());
+            }
+            Ok(_) => {
+                panic!("expected error but got okay");
+            }
+        }
+    }
+}

flipt-evaluation/src/store/mod.rs

@@ -391,4 +391,15 @@ mod tests {
         }
         assert_eq!(found, 2);
     }
+
+    #[test]
+    fn test_blank_snapshot() {
+        let snapshot = Snapshot::blank("staging");
+        let namespace = snapshot.namespace;
+        assert_eq!("staging", namespace._key);
+        assert_eq!(0, namespace.flags.len());
+        assert_eq!(0, namespace.eval_rules.len());
+        assert_eq!(0, namespace.eval_distributions.len());
+        assert_eq!(0, namespace.eval_rollouts.len());
+    }
 }