Mocha 之前和之后的钩子未执行

Question

我正在尝试在本地 cassandra 数据库上运行一个简单的测试，以检查 select 语句是否从表中返回正确的记录数。但是，放置在 before 和 after 块之间的代码不会被调用。结果我的测试就失败了。

var assert = require('assert');
var cassandra = require('cassandra-driver');
var async = require('async');

//Connect to the cassandra cluster, assuming that the keyspace & columnspace already exists
var client = new cassandra.Client({contactPoints: ['127.0.0.1'], keyspace: 'demo'}); 
describe('Cassandra is up and running', function() {
    before(function() {
        //Check if the connection got established successfuly 
        client.connect(function(err) {
            if(err){
                console.log("Oops, something went wrong : " + err);
            }
            console.log('I al here 1');
        });

        //Insert a few data to column space
        var queries = [
        {
        query: 'INSERT INTO users(key, name, emails) VALUES (?, ?, ?)',
        params: ['mick-jagger1', 'Sir Mick Jagger 1', 'mick1@company.com']
        },
        {
        query: 'INSERT INTO users(key, name, emails) VALUES (?, ?, ?)',
        params: ['mick-jagger2', 'Sir Mick Jagger 2', 'mick2@company.com']
        },
        {
        query: 'INSERT INTO users(key, name, emails) VALUES (?, ?, ?)',
        params: ['mick-jagger3', 'Sir Mick Jagger 3', 'mick3@company.com']
        },
        {
        query: 'INSERT INTO users(key, name, emails) VALUES (?, ?, ?)',
        params: ['mick-jagger4', 'Sir Mick Jagger 4', 'mick4@company.com']
        }
        ];

        client.batch(queries, { prepare: true }, function(err) {
            if(err){
                console.log("Oops, something went wrong : " + err);
            }
            console.log('Sample data inserted into column space');
        });
    })

    it('should return 4 when four rows of data are inserted into demo table', function() {
        var count = 0;
        client.execute('SELECT COUNT(*) FROM users', function(err, result) {
            count = result.rows[0];
        });
        assert.equal(4, count);
        console.log("I am here : " + count);
    })

    after(function() {
        client.execute('TRUNCATE users', function(err, result) {
            if(err){
                console.log("Oops, something went wrong : " + err);
            }
        });
    })
})

Answer 1

您的测试正在执行异步操作。您需要使用回调来告诉 mocha 您的 it/before/after 函数何时完成。例如：

before(function(done) {
    // ...
    client.batch(queries, {
        prepare: true
    }, function(err) {
            if (err) {
                console.log("Oops, something went wrong : " + err);
            }
            console.log('Sample data inserted into column space');
            done();
        });
});

和：

it('should return 4 when four rows of data are inserted into demo table', function(done) {
    var count = 0;
    client.execute('SELECT COUNT(*) FROM users', function(err, result) {
        count = result.rows[0];
        assert.equal(4, count);
        console.log("I am here : " + count);
        done();
    });
});