function assertPopulated(entry, column, expectedValue, isPrefixApplied) {
  assertEquals(expectedValue, entry.getField(column));

  var tableName = column.getTable().getEffectiveName();
  var value = isPrefixApplied ?
      entry.row.payload()[tableName][column.getName()] :
      entry.row.payload()[column.getName()];
  assertEquals(expectedValue, value);
}
Asserts that the given column is populated with the given value.
@param {!lf.proc.RelationEntry} entry The entry to be checked.
@param {!lf.schema.Column} column The column to be checked.
@param {string} expectedValue The expected value for the given column.
@param {boolean} isPrefixApplied Whether the values in the payload have been
    prefixed.