arbitrary_source_item_ordering should ignore test modules

Author: alex-semenyuk

clippy_lints/src/arbitrary_source_item_ordering.rs

@@ -4,7 +4,7 @@ use clippy_config::types::{
     SourceItemOrderingTraitAssocItemKind, SourceItemOrderingTraitAssocItemKinds,
     SourceItemOrderingWithinModuleItemGroupings,
 };
-use clippy_utils::diagnostics::span_lint_and_note;
+use clippy_utils::{diagnostics::span_lint_and_note, is_cfg_test};
 use rustc_hir::{
     AssocItemKind, FieldDef, HirId, ImplItemRef, IsAuto, Item, ItemKind, Mod, QPath, TraitItemRef, TyKind, Variant,
     VariantData,
@@ -361,6 +361,10 @@ impl<'tcx> LateLintPass<'tcx> for ArbitrarySourceItemOrdering {
         // as no sorting by source map/line of code has to be applied.
         //
         for item in items {
+            if is_cfg_test(cx.tcx, item.hir_id()) {
+                continue;
+            }
+
             if item.span.in_external_macro(cx.sess().source_map()) {
                 continue;
             }

tests/ui-toml/arbitrary_source_item_ordering/ordering_good.rs

@@ -16,6 +16,7 @@
 //@[bad_conf_4] error-in-other-file:
 //@[bad_conf_5] error-in-other-file:
 //@[bad_conf_6] error-in-other-file:
+//@compile-flags: --test
 
 #![allow(dead_code)]
 #![warn(clippy::arbitrary_source_item_ordering)]