### Question:
InsertOrFailImpl extends BaseSqlPart implements Insert { @Nullable @Override public SqlPart previous() { return null; }  @Override void prependTo(@NotNull final RawSqlBuilder builder); @Nullable @Override SqlPart previous(); @NotNull @Override Into into(@NotNull final String tableName); @NotNull @Override Into into(@Nullable final String databaseName, @NotNull final String tableName);  }### Answer:
@Test public void previous_returnsNullValue() { InsertOrFailImpl insertOrFail = new InsertOrFailImpl(); SqlPart result = insertOrFail.previous(); assertThat(result, is(nullValue())); }