Add a more realistic Batch test (#10511)

* Remove unrealistic tests

* Add test that more closely resembles real usage

ethcore/light/src/types/request/batch.rs

@@ -275,8 +275,7 @@ mod tests {
 	}
 
 	#[test]
-	#[should_panic]
-	fn batch_tx_index_backreference_wrong_output() {
+	fn batch_tx_index_backreference_public_api() {
 		let mut builder = Builder::default();
 		builder.push(Request::HeaderProof(IncompleteHeaderProofRequest {
 			num: 100.into(), // header proof puts hash at output 0.
@@ -286,11 +285,16 @@ mod tests {
 		})).unwrap();
 
 		let mut batch = builder.build();
-		batch.requests[1].fill(|_req_idx, _out_idx| Ok(Output::Number(42)));
 
-		batch.next_complete();
-		batch.answered += 1;
-		batch.next_complete();
+		assert!(batch.next_complete().is_some());
+		let hdr_proof_res = header_proof::Response {
+			proof: vec![],
+			hash: 12.into(),
+			td: 21.into(),
+		};
+		batch.supply_response_unchecked(&hdr_proof_res);
+
+		assert!(batch.next_complete().is_some());
 	}
 
 	#[test]
@@ -310,23 +314,4 @@ mod tests {
 		batch.answered += 1;
 		assert!(batch.next_complete().is_some());
 	}
-
-	#[test]
-	#[should_panic]
-	fn batch_receipts_backreference_wrong_output() {
-		let mut builder = Builder::default();
-		builder.push(Request::HeaderProof(IncompleteHeaderProofRequest {
-			num: 100.into(), // header proof puts hash at output 0.
-		})).unwrap();
-		builder.push(Request::Receipts(IncompleteReceiptsRequest {
-			hash: Field::BackReference(0, 0),
-		})).unwrap();
-
-		let mut batch = builder.build();
-		batch.requests[1].fill(|_req_idx, _out_idx| Ok(Output::Number(42)));
-
-		batch.next_complete();
-		batch.answered += 1;
-		batch.next_complete();
-	}
 }