add a basic test for subfields

Author: ianardee

src/test/java/com/mindee/parsing/v2/InferenceTest.java

@@ -285,6 +285,11 @@ void standardFieldTypes_mustExposeSimpleListFieldValues() throws IOException {
       assertThrows(IllegalStateException.class, listField::getObjectItems);
     }
 
+    private void testObjectSubFieldSimpleString(String fieldName, SimpleField subField) {
+      assertTrue(fieldName.startsWith("subfield_"));
+      assertEquals(subField.getValue(), subField.getStringValue());
+    }
+
     @Test
     @DisplayName("object list fields must be recognised")
     void standardFieldTypes_mustExposeObjectListFieldValues() throws IOException {
@@ -326,8 +331,9 @@ void standardFieldTypes_mustExposeObjectListFieldValues() throws IOException {
         SimpleField itemSubfield1 = itemSubFields.getSimpleField("subfield_1");
         assertInstanceOf(String.class, itemSubfield1.getValue());
         for (Map.Entry<String, SimpleField> entry : itemFields.entrySet()) {
+            String fieldName = entry.getKey();
             SimpleField subfield = entry.getValue();
-            assertEquals(subfield.getValue(), subfield.getStringValue());
+            testObjectSubFieldSimpleString(fieldName, subfield);
         }
       }
 
@@ -354,6 +360,7 @@ void standardFieldTypes_mustExposeObjectFieldValues() throws IOException {
       for (Map.Entry<String, DynamicField> entry : subFieldsDynamic.entrySet()) {
         String fieldName = entry.getKey();
         SimpleField subField = entry.getValue().getSimpleField();
+        testObjectSubFieldSimpleString(fieldName, subField);
       }
 
       LinkedHashMap<String, SimpleField> subFieldsSimple = fieldObject.getSimpleFields();
@@ -363,6 +370,7 @@ void standardFieldTypes_mustExposeObjectFieldValues() throws IOException {
       for (Map.Entry<String, SimpleField> entry : subFieldsSimple.entrySet()) {
         String fieldName = entry.getKey();
         SimpleField subField = entry.getValue();
+        testObjectSubFieldSimpleString(fieldName, subField);
       }
     }
   }