[fix] do not skip empty string values

Author: line-o

exist-core/src/main/java/org/exist/xquery/functions/fn/FunSerialize.java

@@ -163,9 +163,6 @@ public static Sequence normalize(final Expression callingExpr, final XQueryConte
                 // casting it to an xs:string and copy the string representation to the new sequence;"
                 final StringValue stringRepresentation = new StringValue(callingExpr, next.getStringValue());
                 // skip values that evaluate to an empty string
-                if (stringRepresentation.getStringValue().isEmpty()) {
-                    continue;
-                }
                 temp.add(stringRepresentation);
             }
         }

exist-core/src/test/xquery/xquery3/serialize.xql

@@ -958,31 +958,38 @@ function ser:sequence-of-nodes() {
 declare
     %test:assertEquals("[|]")
 function ser:sequence-skip-empty-text-node() {
-    fn:serialize((<a>[</a>, <a>
-    </a>, <a>]</a>)/text(), map {"item-separator": "|"})
+    (<a>[</a>, <a>
+        </a>, <a>]</a>)/text()
+    => serialize(map {"item-separator": "|"})
 };
 
+declare
+    %test:assertEquals("||")
+function ser:sequence-dont-skip-empty-string() {
+    serialize(("", "", ""), map {"item-separator": "|"})
+};
 
 declare
     %test:assertEquals("foo")
 function ser:skip-empty-no-separator() {
-    (<a>foo</a>, <b></b>)/text() => serialize(map{"item-separator": "!"})
+    (<a>foo</a>, <b></b>)/text()
+    => serialize(map{"item-separator": "!"})
 };
 
 declare
     %test:assertEquals("")
 function ser:empty-array-serializes-to-empty-string() {
-    [] => serialize()
+    serialize([])
 };
 
 declare
     %test:assertEquals("")
 function ser:array-with-members-serializes-to-empty-string() {
-    ["", ()] => serialize()
+    serialize(["", ()])
 };
 
 declare
-    %test:assertEquals("")
+    %test:assertEquals("|")
 function ser:sequence-of-empty-arrays-serializes-to-empty-string() {
-    ([],[]) => serialize()
+    serialize(([],[]), map{"item-separator": "|"})
 };