- Mastering React Test：Driven Development
- Daniel Irvine
- 159字
- 2021-06-24 14:45:03
Using a beforeEach block
Both of our tests start with some setup or arrangement. When that setup is common to all tests, we can promote them into a beforeEach block instead. Code in this block is executed before each test.
Above your first test, write the following code, and delete the corresponding call to createElement from each of your two tests:
beforeEach(() => {
container = document.createElement('div');
});
Since we defined container in the scope of the describe block, the value set here in the beforeEach block will be available to our test once it executes.
Be careful when you use variables defined within the describe scope. These variables are not cleared between each test execution, so you are running the risk of non-independent tests. Therefore, any variable you declare in the describe scope should be assigned to a new value in a corresponding beforeEach block, or in the first part of each test, just as we've done here.