前言

在撰寫測試單元的時候，有時需要模擬將資料發送到外部網站的情況。為了實現這一點，需要自行編寫一個自定義的模擬（Mock），並在測試單元中將其實現。

• Need Callout Class Example

1
2
3
4
5
6
7
8
9
10
public class CalloutClass {
    public static HttpResponse getInfoFromExternalService() {
        HttpRequest req = new HttpRequest();
        req.setEndpoint('https://example.com/example/test');
        req.setMethod('GET');
        Http h = new Http();
        HttpResponse res = h.send(req);  //打出Response
        return res;
    }
}

• 創建 Mock 並使用 HttpCalloutMock Interface 模擬 Response

MockForTestmethod.cls

1
2
3
4
5
6
7
8
9
10
11
global class YourHttpCalloutMockImpl implements HttpCalloutMock {
    global HTTPResponse respond(HTTPRequest req) {
        // Create a fake response.Set response values
        HttpRequest req = new HttpRequest();
        req.setEndpoint('https://example.com/example/test');
        req.setMethod('GET');
        Http h = new Http();
        HttpResponse res = h.send(req);
        return res;
    }
}

• 在測試單元加上 Test.setMock

Test_blogExample.cls

1
Test.setMock(HttpCalloutMock.class, new YourHttpCalloutMockImpl());
1
2
3
4
5
6
7
8
9
10
11
12
@isTest
private class CalloutClassTest {
     @isTest static void testCallout() {
        // Set mock callout class 
        Test.setMock(HttpCalloutMock.class, new MockHttpResponseGenerator());
        
        // This causes a fake response to be sent
        // From the class that implements HttpCalloutMock. 
        HttpResponse res = CalloutClass.getInfoFromExternalService();
    }
}

學習參考：Salesforce Apex Developer Guide