Preserve insertion order in EolMap

Author: kolovos

plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/types/EolMap.java

@@ -12,6 +12,7 @@
 package org.eclipse.epsilon.eol.types;
 
 import java.util.Collection;
+import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
@@ -33,7 +34,7 @@ protected EolMap(Map<K, V> mapImpl) {
 	}
 
 	public EolMap() {
-		this(new java.util.HashMap<>());
+		this(new LinkedHashMap<K, V>());
 	}
 
 	@Override

tests/org.eclipse.epsilon.eol.engine.test.acceptance/src/org/eclipse/epsilon/eol/engine/test/acceptance/CollectionsTests.eol

@@ -552,3 +552,23 @@ operation emptyMapKeyToString(){
 operation emptyMapValueToString(){
 	assertEquals("Map {1->\"\"}", Map{1=""}.asString());
 }
+
+@test
+operation setPreservesInsertionOrder() {
+	var s : new Set;
+	var items = Sequence{5, 3, 2, 7};
+	for (item in items) {
+		s.add(item);
+	}
+	assertEquals(items, s.asSequence());
+}
+
+@test
+operation mapPreservesInsertionOrder() {
+	var m : new Map;
+	var keys = Sequence{5, 3, 2, 7};
+	for (k in keys) {
+		m.put(k, k+1);
+	}
+	assertEquals(keys, m.keySet().asSequence());
+}