Android 单元测试断言校验方法 org.junit.Assert

判断布尔值

assertTrue

assertFalse

判断对象非空

assertNull(object);

 案例：

PersistableBundle result = Util.getCarrierConfig(mockContext, subId);assertNull(result);

 

判断是否相等

assertEquals("mocked_string", result.toString());

package org.junit;public class Assert {/*** Asserts that two objects are equal. If they are not, an* {@link AssertionError} without a message is thrown. If* <code>expected</code> and <code>actual</code> are <code>null</code>,* they are considered equal.** @param expected expected value* @param actual the value to check against <code>expected</code>*/public static void assertEquals(Object expected, Object actual) {assertEquals(null, expected, actual);}
}

可以用于字符串比较，比如下面的查询条件拼接

//测试类
public class ApnSettingsTest {@Testpublic void testGetFillListQuery_initialWhereEmpty() {StringBuilder where = new StringBuilder();int subId = 1;// Mock the behavior of getSelection methodwhen(mFragment.getSelection("", subId)).thenReturn("mocked_selection");StringBuilder result = mFragment.getFillListQuery(where, subId);// Verify the `where` has the expected selectionassertEquals("mocked_selection", result.toString());// Check log output (Could use a library or a custom handler to intercept logs)// For simplicity, assuming log validation is part of the manual test validation process.}//TODO: 存在问题的测试接口，为什么其他两个getSelection可以返回预期？？@Testpublic void testGetFillListQuery_initialWhereNonEmpty() {StringBuilder where = new StringBuilder("existing_condition");int subId = 1;// Mock the behavior of getSelection method，没生效？when(mFragment.getSelection("existing_condition", subId)).thenReturn(" AND mocked_selection");StringBuilder result = mFragment.getFillListQuery(where, subId);// Verify the `where` has the expected selection// 校验存在问题assertEquals("existing_condition AND mocked_selection", result.toString());// Check log output similarly as mentioned in previous test}@Testpublic void testGetFillListQuery_differentSubId() {StringBuilder where = new StringBuilder();int subId = 2;// Mock the behavior of getSelection methodwhen(mFragment.getSelection("", subId)).thenReturn("different_selection");StringBuilder result = mFragment.getFillListQuery(where, subId);// Verify the `where` has the expected selectionassertEquals("different_selection", result.toString());// Check log output similarly as mentioned in previous tests}}//被测试类
public class DemoSettings {@VisibleForTestingStringBuilder getFillListQuery(StringBuilder where, int subId) {String selection = "";selection = getSelection(selection, subId);where.append(selection);    // 拼接新增的过滤条件return where;}/*** Customize the cursor select conditions with subId releated to SIM.*/String getSelection(String selection, int subId) {boolean isCustomized = true;Context context = getContext();if (context != null) {isCustomized = SubscriptionManager.getResourcesForSubId(getContext().getApplicationContext(), subId).getBoolean(R.bool.config_is_customize_selection);}if(!isCustomized) return selection;// 注意有两个双引号的地方：第一个转义"，第二个是字符串匹配// 拼接的查询语句等效于：// (type = 0 or sub_id = $传入值)// SQL 查询语句：// SELECT *// FROM your_table// WHERE status = 'active' AND (type = "0" OR sub_id = "subId");String where = "(" + " type =\"" + "0" + "\"";where += " or sub_id =\"" + subId + "\"";where += " or type =\"" + "2" + "\"" + ")";selection = selection + " and " + where;return where;}// Additional tests could be written to consider edge cases, such as:// - Negative subId values// - Null or invalid StringBuilder where value// In real scenario, depending on codebase other relevant checks can also be added.}

上述代码校验存在问题，报错如下：

Expected :existing_condition AND mocked_selection
Actual   :existing_condition and (type ="0" or sub_id ="1" or type ="2")
<Click to see difference>

org.junit.ComparisonFailure: expected:<existing_condition [AND mocked_selection]> but was:<existing_condition [and (type ="0" or sub_id ="1" or type ="2")]>

修改后pass的逻辑，因为内部会自己创建where值，不知道为什么不按 when.thenReturn 的返回 mocked_selection。

    @Testpublic void testGetFillListQuery_initialWhereNonEmpty() {StringBuilder where = new StringBuilder("existing_condition");int subId = 1;// Mock the behavior of getSelection methodwhen(mFragment.getSelection("", subId)).thenReturn(" and (type ='0' or sub_id ='1' or type ='2')");StringBuilder result = mFragment.getFillListQuery(where, subId);// Verify the `where` has the expected selectionassertEquals("existing_condition and (type ='0' or sub_id ='1' or type  ='2')",result.toString());}