### Question:
RecordStructureDocumentation extends AbstractDocumentation { @Override public int hashCode() { final int prime = 31; int result = super.hashCode(); result = prime * result + fields.hashCode(); result = prime * result + ((structureType == null) ? 0 : structureType.hashCode()); return result; } RecordStructureDocumentation(final String description, final InterfaceStructureType structureType,
            final List<Field> fields); @Override boolean equals(final Object obj); List<Field> getFields(); InterfaceStructureType getStructureType(); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void testEqualsNullStructureType() { final RecordStructureDocumentation nullType = new RecordStructureDocumentation(description, null, fields); assertThat(doc).isNotEqualTo(nullType); assertThat(nullType).isNotEqualTo(doc); assertThat(doc.hashCode()).isNotEqualTo(nullType.hashCode()); }