FilterExpression implements Expression, Configurable { @Override public String[] getUsage() { if (expression != null) { return expression.getUsage(); } return null; } protected  FilterExpression(Expression expression); @Override void setOptions(FindOptions options); @Override void prepare(); @Override Result apply(PathData item, int depth); @Override void finish(); @Override String[] getUsage(); @Override String[] getHelp(); @Override boolean isAction(); @Override boolean isOperator(); @Override int getPrecedence(); @Override void addChildren(Deque<Expression> expressions); @Override void addArguments(Deque<String> args); @Override void setConf(Configuration conf); @Override Configuration getConf(); @Override String toString();  }
@Test public void getUsage() { String[] usage = new String[] { "Usage 1", "Usage 2", "Usage 3" }; when(expr.getUsage()).thenReturn(usage); assertArrayEquals(usage, test.getUsage()); verify(expr).getUsage(); verifyNoMoreInteractions(expr); }