這篇文章主要介紹Angular中如何進行單元測試的方法，文中介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們一定要看完！
前言
之前對單元測試的認知就是復雜，難搞，思路有，就是不知道怎樣去實現，最近一次開會解決問題的過程中，發現原來單元測試可以十分簡單，簡單到幾行代碼就能實現。
示例
下面代碼實現的功能是，判斷課程所在的學院<College> college是否在用戶所有的學院Array<College> colleges中，如果存在，變量show賦值為true，不存在，則賦值為false，如果college為undefined或者null，也賦值為true。
/**
* 觀察課程學院是否與用戶所在學院相同
* @param college 課程學院
* @param colleges 用戶學院
*/
public whetherShow(college: { id: number }, colleges: Array<{ id: number }>) {
Assert.notNull(college, 'college未定義');
const collegeId = college.id;
let show = colleges != null && colleges && colleges.length > 0 ? false : true;
if (colleges != null) {
colleges.forEach(selectCollege => {
if (collegeId === selectCollege.id) {
show = true;
}
});
}
return show;
}要對該方法進行單元測試，思路就是傳值進去進行對比，重點在于傳值，用之前的思路就是，定義college和colleges,然后進行對比：
it('is show', () => {
const course = new Course({id: 1})
const collegeOne = new College({id: 1});
const collegeTwo = new College({id: 2});
component.colleges = [];
expect(component.whetherShow(course,component.colleges)).toBe(true);
component.colleges = undefined;
expect(component.whetherShow(course,component.colleges)).toBe(true);
component.colleges = [collegeOne];
expect(component.whetherShow(course,component.colleges)).toBe(true);
component.colleges = [collegeTwo];
expect(component.whetherShow(course,component.colleges)).toBe(false);
component.colleges = [collegeOne, collegeTwo];
expect(component.whetherShow(course,component.colleges)).toBe(true);
});
通過控制臺的信息可以發現，無論是null還是undefined，都是可以通過的，后來老師提供了新的思路，既然要測試的是功能，就不要管怎么傳的，可以不用傳對象，然后就有了下面的寫法：
it('is show', () => {
expect(component.whetherShow({id: 1}, null)).toBe(true);
expect(component.whetherShow({id: 1}, undefined)).toBe(true);
expect(component.whetherShow({id: 1}, [])).toBe(true);
expect(component.whetherShow({id: 1}, [{id: 2}, {id: 3}])).toBe(false);
expect(component.whetherShow({id: 1}, [{id: 1}, {id: 2}, {id: 3}])).toBe(true);
expect(component.whetherShow({id: 1}, [{id: 2}, {id: 3}, {id: 1}])).toBe(true);
});值傳進去了，方法也能判斷了，比起之前的寫法簡直要好太多，而且對于一些方法來說，這種方法省力不少，尤其是對多種情況進行測試，要進行多個變量的定義：
/**
* 判斷查詢的關鍵字是否課程代碼或名稱中
* @param course 課程
* @param searchKey 查詢關鍵字
*/
public isCodeOrNameContainsSearchKey(course: { code: string, name: string }, searchKey: string) {
return searchKey === null
|| course.code.toLowerCase().indexOf(searchKey.toLowerCase()) !== -1
|| course.name.toLowerCase().indexOf(searchKey.toLowerCase()) !== -1;
}該方法實現的是通過課程名稱或代碼進行查詢操作，通過對查詢關鍵字和課程名稱或代碼進行對比實現該功能，要考慮以下幾種情況：查詢關鍵字為null、查詢關鍵字與課程名稱或代碼部分完全不相同、查詢關鍵字與課程名稱或代碼部分相同、查詢關鍵字與課程名稱或代碼完全相同、查詢關鍵字包含課程名稱或代碼。
如果用舊思想進行測試：
it('isCodeOrNameContainsSearchKey', () => {
const courseOne = new Course({code: '', name: ''});
const courseTwo = new Course({code: '222', name: ''});
const courseThree = new Course({code: '', name: '222'});
const courseFour = new Course({code: '222', name: '222'});
expect(component.isCodeOrNameContainsSearchKey(courseOne, null));
expect(component.isCodeOrNameContainsSearchKey(courseOne, ''));
expect(component.isCodeOrNameContainsSearchKey(courseTwo, ''));
expect(component.isCodeOrNameContainsSearchKey(courseTwo, '1111'));
expect(component.isCodeOrNameContainsSearchKey(courseTwo, '22'));
expect(component.isCodeOrNameContainsSearchKey(courseTwo, '222'));
expect(component.isCodeOrNameContainsSearchKey(courseTwo, '2222'));
expect(component.isCodeOrNameContainsSearchKey(courseThree, ''));
expect(component.isCodeOrNameContainsSearchKey(courseThree, '1111'));
expect(component.isCodeOrNameContainsSearchKey(courseThree, '22'));
expect(component.isCodeOrNameContainsSearchKey(courseThree, '222'));
expect(component.isCodeOrNameContainsSearchKey(courseThree, '2222'));
expect(component.isCodeOrNameContainsSearchKey(courseFour, ''));
expect(component.isCodeOrNameContainsSearchKey(courseFour, '1111'));
expect(component.isCodeOrNameContainsSearchKey(courseFour, '22'));
expect(component.isCodeOrNameContainsSearchKey(courseFour, '222'));
expect(component.isCodeOrNameContainsSearchKey(courseFour, '2222'));
});如果使用新思想：
it('isCodeOrNameContainsSearchKey', () => {
expect(component.isCodeOrNameContainsSearchKey({code: '', name: ''}, null)).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '', name: ''}, '')).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '222', name: ''}, '')).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '222', name: ''}, '1111')).toBe(false);
expect(component.isCodeOrNameContainsSearchKey({code: '222', name: ''}, '22')).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '222', name: ''}, '222')).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '222', name: ''}, '2222')).toBe(false);
expect(component.isCodeOrNameContainsSearchKey({code: '', name: '222'}, '')).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '', name: '222'}, '1111')).toBe(false);
expect(component.isCodeOrNameContainsSearchKey({code: '', name: '222'}, '22')).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '', name: '222'}, '222')).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '', name: '222'}, '2222')).toBe(false);
expect(component.isCodeOrNameContainsSearchKey({code: '222', name: '222'}, '')).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '222', name: '222'}, '1111')).toBe(false);
expect(component.isCodeOrNameContainsSearchKey({code: '222', name: '222'}, '22')).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '222', name: '222'}, '222')).toBe(true);
expect(component.isCodeOrNameContainsSearchKey({code: '222', name: '222'}, '2222')).toBe(false);
});設想一下自己看到他人寫的測試代碼，如果所需要的變量很少，courseOne等等能滿足需求，看著也沒問題，但是當變量很多的時候，估計寫測試的都會忘記每個變量的屬性值，更不用說看的人，而且，使用下面的方法寫的代碼，所需字段以及字段值一目了然，一行代碼就能體現所有信息，看著也賞心悅目。
以上是Angular中如何進行單元測試的方法的所有內容，感謝各位的閱讀！希望分享的內容對大家有幫助，更多相關知識，歡迎關注億速云行業資訊頻道！
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