Refactor candidates test in paras_inherent (#2004)

Splits the test in multiple cases.

Author: tdimitrov

polkadot/runtime/parachains/src/paras_inherent/tests.rs

@@ -1205,9 +1205,17 @@ mod sanitizers {
 		}
 	}
 
-	#[test]
-	fn candidates() {
-		new_test_ext(MockGenesisConfig::default()).execute_with(|| {
+	mod candidates {
+		use super::*;
+
+		// Backed candidates and scheduled parachains used for `sanitize_backed_candidates` testing
+		struct TestData {
+			backed_candidates: Vec<BackedCandidate>,
+			scheduled_paras: BTreeMap<primitives::Id, CoreIndex>,
+		}
+
+		// Generate test data for the candidates test
+		fn get_test_data() -> TestData {
 			const RELAY_PARENT_NUM: u32 = 3;
 
 			let header = default_header();
@@ -1233,9 +1241,6 @@ mod sanitizers {
 				.unwrap();
 			}
 
-			let has_concluded_invalid =
-				|_idx: usize, _backed_candidate: &BackedCandidate| -> bool { false };
-
 			let scheduled = (0_usize..2)
 				.into_iter()
 				.map(|idx| (ParaId::from(1_u32 + idx as u32), CoreIndex::from(idx as u32)))
@@ -1278,29 +1283,54 @@ mod sanitizers {
 				})
 				.collect::<Vec<_>>();
 
-			// happy path
-			assert_eq!(
-				sanitize_backed_candidates::<Test, _>(
-					backed_candidates.clone(),
-					has_concluded_invalid,
-					&scheduled
-				),
-				backed_candidates
-			);
+			TestData { backed_candidates, scheduled_paras: scheduled }
+		}
 
-			// nothing is scheduled, so no paraids match, thus all backed candidates are skipped
-			{
+		#[test]
+		fn happy_path() {
+			new_test_ext(MockGenesisConfig::default()).execute_with(|| {
+				let TestData { backed_candidates, scheduled_paras: scheduled } = get_test_data();
+
+				let has_concluded_invalid =
+					|_idx: usize, _backed_candidate: &BackedCandidate| -> bool { false };
+
+				assert_eq!(
+					sanitize_backed_candidates::<Test, _>(
+						backed_candidates.clone(),
+						has_concluded_invalid,
+						&scheduled
+					),
+					backed_candidates
+				);
+
+				{}
+			});
+		}
+
+		// nothing is scheduled, so no paraids match, thus all backed candidates are skipped
+		#[test]
+		fn nothing_scheduled() {
+			new_test_ext(MockGenesisConfig::default()).execute_with(|| {
+				let TestData { backed_candidates, scheduled_paras: _ } = get_test_data();
 				let scheduled = &BTreeMap::new();
+				let has_concluded_invalid =
+					|_idx: usize, _backed_candidate: &BackedCandidate| -> bool { false };
+
 				assert!(sanitize_backed_candidates::<Test, _>(
 					backed_candidates.clone(),
 					has_concluded_invalid,
 					&scheduled
 				)
 				.is_empty());
-			}
+			});
+		}
+
+		// candidates that have concluded as invalid are filtered out
+		#[test]
+		fn invalid_are_filtered_out() {
+			new_test_ext(MockGenesisConfig::default()).execute_with(|| {
+				let TestData { backed_candidates, scheduled_paras: scheduled } = get_test_data();
 
-			// candidates that have concluded as invalid are filtered out
-			{
 				// mark every second one as concluded invalid
 				let set = {
 					let mut set = std::collections::HashSet::new();
@@ -1322,7 +1352,7 @@ mod sanitizers {
 					.len(),
 					backed_candidates.len() / 2
 				);
-			}
-		});
+			});
+		}
 	}
 }