test: verify empty collection rule ids

Author: carstenartur

sandbox_common_core/src/test/java/org/sandbox/jdt/triggerpattern/test/BundledHintRuleBehaviorTest.java

@@ -13,6 +13,7 @@
  *******************************************************************************/
 package org.sandbox.jdt.triggerpattern.test;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.BeforeEach;
@@ -77,6 +78,21 @@ void collectionsKeepsSafeEmptyCollectionFactoryReplacements() throws Exception {
 				"class Test { Object m() { return java.util.Set.of(); } }"); //$NON-NLS-1$
 	}
 
+	@Test
+	void collectionsUsesStableRuleIdsForEmptyCollectionFactories() throws Exception {
+		HintFile hintFile = loadBundledHint("collections.sandbox-hint"); //$NON-NLS-1$
+
+		assertEquals("collections.empty-list.to-list-of", //$NON-NLS-1$
+				process(hintFile, "class Test { Object m() { return java.util.Collections.emptyList(); } }") //$NON-NLS-1$
+						.get(0).rule().getRuleId());
+		assertEquals("collections.empty-map.to-map-of", //$NON-NLS-1$
+				process(hintFile, "class Test { Object m() { return java.util.Collections.emptyMap(); } }") //$NON-NLS-1$
+						.get(0).rule().getRuleId());
+		assertEquals("collections.empty-set.to-set-of", //$NON-NLS-1$
+				process(hintFile, "class Test { Object m() { return java.util.Collections.emptySet(); } }") //$NON-NLS-1$
+						.get(0).rule().getRuleId());
+	}
+
 	@Test
 	void collectionsRespectsJava9SourceVersionGuard() throws Exception {
 		HintFile hintFile = loadBundledHint("collections.sandbox-hint"); //$NON-NLS-1$