@Test
public void setChild() throws Exception {

  TernaryExpr te = makeTernary();
  te.setChild(0, elseVar);
  te.setChild(1, conditionVar);
  te.setChild(2, thenVar);
  assertEquals(elseVar, te.getTest());
  assertEquals(conditionVar, te.getThenExpr());
  assertEquals(thenVar, te.getElseExpr());
}