@Test
    void requireThatAddingCollectionTypeIsNotOK() throws Exception {
        Fixture f = new Fixture("field f1 type string { indexing: summary }",
                "field f1 type array<string> { indexing: summary }");
        Instant.now();
        f.assertValidation(newRefeedAction(ClusterSpec.Id.from("test"), ValidationId.fieldTypeChange, "Field 'f1' changed: data type: 'string' -> 'Array<string>'"));
    }
Test validation of changes between a current and next document type used in a document database.

@author toregge
config-model/src/test/java/com/yahoo/vespa/model/application/validation/change/search/DocumentTypeChangeValidatorTest.java