Fix emitting nested arrays.

Nested arrays would always be flattened: metafacture/metafacture-fix#244 (comment)

Author: blackwinter

metafix/src/main/java/org/metafacture/metafix/Metafix.java

@@ -218,7 +218,7 @@ private void emit(final String field, final Value value) {
                 final String fieldName = isMulti ? String.valueOf(i + 1) : field;
 
                 currentValue.matchType()
-                    .ifArray(a -> emit(fieldName, currentValue))
+                    .ifArray(a -> emit(isMulti ? fieldName + ARRAY_MARKER : fieldName, currentValue))
                     .ifHash(h -> {
                         outputStreamReceiver.startEntity(fieldName);
                         h.forEach(this::emit);

metafix/src/test/java/org/metafacture/metafix/MetafixMethodTest.java

@@ -2255,7 +2255,6 @@ public void shouldCopyToFieldWithTwoReservedFieldNames() {
     }
 
     @Test
-    @MetafixToDo("Existing value has no path ('[[a]]'), resulting in wrong path for new value")
     public void shouldMoveFieldToPathWithIndexAndReservedField() {
         MetafixTestHelpers.assertFix(streamReceiver, Arrays.asList(
                 "move_field('b', 'names[].1.$append')"
@@ -2283,7 +2282,6 @@ public void shouldMoveFieldToPathWithIndexAndReservedField() {
     }
 
     @Test
-    @MetafixToDo("Existing value has no path ('[[a]]'), resulting in wrong path for new value")
     public void shouldMoveFieldToPathWithTwoReservedFields() {
         MetafixTestHelpers.assertFix(streamReceiver, Arrays.asList(
                 "move_field('b', 'names[].$first.$append')"
@@ -2825,7 +2823,6 @@ public void moveToNestedArray() {
     }
 
     @Test
-    @MetafixToDo("Arrays in arrays need to be preserved. See disabled isArray in FixPath#appendIn.")
     public void shouldSplitMarkedArrayFieldIntoArrayOfArrays() {
         MetafixTestHelpers.assertFix(streamReceiver, Arrays.asList(
                 "split_field('date[]', '-')"

metafix/src/test/java/org/metafacture/metafix/MetafixRecordTest.java

@@ -2456,12 +2456,12 @@ public void shouldDeleteEmptyArraysInArrays() {
                 i.endEntity();
                 i.endRecord();
             },
-            o -> {
+            (o, f) -> {
                 o.get().startRecord("1");
                 o.get().startEntity("arrays[]");
-                // TODO: Preserve nested array!? (`1[]`)
+                o.get().startEntity("1[]");
                 o.get().literal("1", ":-P yuck");
-                o.get().endEntity();
+                f.apply(2).endEntity();
                 o.get().endRecord();
             }
         );
@@ -2564,6 +2564,63 @@ public void transformRepeatedField() {
         );
     }
 
+    @Test
+    public void shouldEmitNestedArray() {
+        MetafixTestHelpers.assertFix(streamReceiver, Arrays.asList(
+                "nothing()"
+            ),
+            i -> {
+                i.startRecord("1");
+                i.startEntity("test");
+                i.startEntity("zoo[]");
+                i.startEntity("1");
+                i.startEntity("animals[]");
+                i.startEntity("1[]");
+                i.literal("1", "ant");
+                i.literal("2", "dog");
+                i.endEntity();
+                i.literal("2", "cat");
+                i.startEntity("3[]");
+                i.literal("1", "fish");
+                i.startEntity("2[]");
+                i.literal("1", "zebra");
+                i.literal("2", "horse");
+                i.endEntity();
+                i.literal("3", "hippo");
+                i.endEntity();
+                i.literal("4", "giraffe");
+                i.endEntity();
+                i.endEntity();
+                i.endEntity();
+                i.endEntity();
+                i.endRecord();
+            },
+            (o, f) -> {
+                o.get().startRecord("1");
+                o.get().startEntity("test");
+                o.get().startEntity("zoo[]");
+                o.get().startEntity("1");
+                o.get().startEntity("animals[]");
+                o.get().startEntity("1[]");
+                o.get().literal("1", "ant");
+                o.get().literal("2", "dog");
+                o.get().endEntity();
+                o.get().literal("2", "cat");
+                o.get().startEntity("3[]");
+                o.get().literal("1", "fish");
+                o.get().startEntity("2[]");
+                o.get().literal("1", "zebra");
+                o.get().literal("2", "horse");
+                o.get().endEntity();
+                o.get().literal("3", "hippo");
+                o.get().endEntity();
+                o.get().literal("4", "giraffe");
+                f.apply(4).endEntity();
+                o.get().endRecord();
+            }
+        );
+    }
+
     @Test
     public void emitEntityForRepeatedField() {
         MetafixTestHelpers.assertFix(streamReceiver, Arrays.asList(