junit.framework包下的Assert提供了多个断言方法. 主用于比较测试传递进去的两个参数.
Assert.assertEquals();及其重载方法: 1. 如果两者一致, 程序继续往下运行. 2. 如果两者不一致, 中断测试方法, 抛出异常信息 AssertionFailedError .
查看源码, 以Assert.assertEquals(int expected, int actual)为例:
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/** * Asserts that two ints are equal. 断言两个int是相等的 */ static public void assertEquals( int expected, int actual) { assertEquals( null , expected, actual); } |
可以看到里面调用了assertEquals(String message, int expected, int actual)方法:
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/** * Asserts that two ints are equal. If they are not * an AssertionFailedError is thrown with the given message. * 如果不抛出带有 message 的异常(AssertionFailedError)信息, 则表明两者相等 */ static public void assertEquals(String message, int expected, int actual) { assertEquals(message, Integer.valueOf(expected), Integer.valueOf(actual)); } |
可以看到, 这里把int类型封箱成为Integer类型. 注释说, 会抛异常, 但这里没有. 没关系, 我们接着看里面调用: assertEquals(String message, Object expected, Object actual)方法:
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/** * Asserts that two objects are equal. If they are not * an AssertionFailedError is thrown with the given message. * 如果不抛出带有 message 的异常(AssertionFailedError)信息, 则表明两者相等(这里比较的是Object对象) */ static public void assertEquals(String message, Object expected, Object actual) { if (expected == null && actual == null ) { return ; } if (expected != null && expected.equals(actual)) { return ; } failNotEquals(message, expected, actual); } |
两个if语句, 判断了两者相等的情况: 引用(地址)相等或者内容相等. 如果这两种if情况都不命中, 那么表明1参和2参实际是不相等, 所以代码会往下执行failNotEquals(String message, Object expected, Object actual)方法，并在此方法中抛出异常, 接下来就比较简单了:
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static public void failNotEquals(String message, Object expected, Object actual) { fail(format(message, expected, actual)); }
public static String format(String message, Object expected, Object actual) { String formatted = "" ; if (message != null && message.length() > 0 ) { formatted = message + " " ; } return formatted + "expected:<" + expected + "> but was:<" + actual + ">" ; } /** * Fails a test with the given message. */ static public void fail(String message) { if (message == null ) { throw new AssertionFailedError(); } throw new AssertionFailedError(message); } |
以上可以看出, 最终是由fail(String message)这个方法抛出异常信息!!
Assert.assertEquals()使用方法:
使用, 示例代码:
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Assert.assertEquals( true , arry.contains( "hello" )); Assert.assertEquals(39991L, aa.getLong( "key3" , 0L)); Assert.assertEquals( true , bb.getBoolean( "key4" , false )); Assert.assertEquals( 5 .3f, cc.getFloat( "key5" , 0 .f)); Assert.assertEquals( 99 , dd.getInt( "key6" , 1 )); Assert.assertEquals( "如果打印本信息, 证明参数不相等" , 10L, 10 ); |
按照源码分析, 我们可以把一个预期结果作为1参传递进去. 2参传递我们需要测试的方法. 然后执行. 相等, 代码继续往下执行, 不相等, 中断执行, 抛出异常信息!!!
略作一提:
Assert.assertSame(Object expected, Object actual)方法:
查看源码, 其比较的是引用地址是否相等, 并没有对内容进行比较:
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/** * Asserts that two objects refer to the same object. If they are not * the same an AssertionFailedError is thrown. */ static public void assertSame(Object expected, Object actual) { assertSame( null , expected, actual); } /** * Asserts that two objects refer to the same object. If they are not * an AssertionFailedError is thrown with the given message. */ static public void assertSame(String message, Object expected, Object actual) { if (expected == actual) { return ; } failNotSame(message, expected, actual); } |
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原文链接：https://blog.csdn.net/tgvincent/article/details/81296349
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