@Test
    public void testMatchCannotAssignToMap() {
        // Unsupported value type for map value assign.
        assertEquals("Field type Map<string,string> not supported.",
                     assertThrows(UnsupportedOperationException.class,
                                  () -> parseUpdate("""
                                                    {
                                                      "update": "id:unittest:testmap::whee",
                                                      "fields": {
                                                        "actualmap": {
                                                          "match": {
                                                            "element": "bamse",
                                                            "assign": "bar"
                                                          }
                                                        }
                                                      }
                                                    }
                                                    """)).getMessage());
    }
Basic test of JSON streams to Vespa document instances.

@author Steinar Knutsen
@author bratseth
document/src/test/java/com/yahoo/document/json/JsonReaderTestCase.java