PHP query function test case

As a developer, writing the query function code does not mean that the task is completed. Test cases are also needed to ensure the correctness and reliability of the code. This article will write test cases for the PHP query function to help developers better understand and improve code quality.

1. What is a test case?

A test case is a set of unit tests that developers use to check that code conforms to specifications. Test cases can be used for automated testing. Use test cases to test the code before committing it or deploying the code to the production environment to ensure that the code works properly under various circumstances and does not cause exceptions.

For example, suppose we want to write a function that queries the database. The test case can simulate various data inputs to test the output of the function. This will help us ensure functionality is consistent with desired results and eliminate bugs and bugs in the code.

2. Test Case: Preparation

Before writing the test case, we need to prepare the test environment and the PHP query function that needs to be tested. There are two more common PHP query functions for testing, taking mysqli as an example:

//连接数据库
$connect = mysqli_connect("localhost","username","password");
//选择数据库
mysqli_select_db($connect,"databasename");
//查询数据
$result = mysqli_query($connect,"SELECT * FROM table_name");

Test case example one:

Test case one checks whether our connection is working properly. We can enter some wrong parameters at will to test whether the connection will fail due to wrong parameters.

//测试用例一：连接测试
public function test_connection() {
    $host = 'localhost';
    $username = 'root';
    $password = '';
    $database = 'test';

    //测试1：错误的主机名
    $conn = mysqli_connect('error', $username, $password, $database);
    $this->assertFalse($conn);

    //测试2：错误的用户名
    $conn = mysqli_connect($host, 'error', $password, $database);
    $this->assertFalse($conn);

    //测试3：错误的密码
    $conn = mysqli_connect($host, $username, 'error', $database);
    $this->assertFalse($conn);

    //测试4：错误的数据库
    $conn = mysqli_connect($host, $username, $password, 'error');
    $this->assertFalse($conn);

    //测试5：成功连接
    $conn = mysqli_connect($host, $username, $password, $database);
    $this->assertTrue($conn !== false);
}

Test case example two:

Test case two checks whether the query statement can be executed successfully and returns correct data. We can enter any data to check whether the query statement is working properly.

//测试用例二：数据查询
public function test_data_query() {
    //连接数据库
    $host = 'localhost';
    $username = 'root';
    $password = '';
    $database = 'test';
    $mysqli = mysqli_connect($host, $username, $password, $database);

    //插入测试数据
    mysqli_query($mysqli, "INSERT INTO `users`(`id`, `name`, `email`) VALUES (1,'Bob','bob@test.com')");
    mysqli_query($mysqli, "INSERT INTO `users`(`id`, `name`, `email`) VALUES (2,'Alice','alice@test.com')");

    //测试1：查询全部数据是否正确
    $result = mysqli_query($mysqli, "SELECT * FROM `users`");
    $this->assertEquals(mysqli_num_rows($result), 2);

    //测试2：查询指定条件的人是否正确
    $result = mysqli_query($mysqli, "SELECT * FROM `users` WHERE `name` = 'Bob'");
    $this->assertEquals(mysqli_num_rows($result), 1);

    //测试3：查询不存在的数据是否返回空结果集
    $result = mysqli_query($mysqli, "SELECT * FROM `users` WHERE `name` = 'John'");
    $this->assertEquals(mysqli_num_rows($result), 0);

    mysqli_close($mysqli);
}

The above are two basic test case examples. We can write more test cases according to needs to test the code more comprehensively and ensure code quality.

3. Test Cases: Notes

When writing test cases, you need to pay attention to the following points:

1. The process of clearing the test environment to ensure each linear test will not affect each other.
2. Test cases should preferably cover all situations that the query statement may encounter.
3. Test cases should provide correct input data and expected output data (or exceptions).
4. Try to use code coverage checking tools to detect the coverage of each test case.

5. Summary of test cases

Good code testing can improve code quality and even help developers better understand the input and output data required by the code. For complex systems, better test coverage can enhance system reliability.

Here, we start from the basic principles of test cases to practical applications. In the process of writing PHP query function test cases, we can not only make the code more reliable, but also improve development efficiency.

Finally, I hope this article can help developers improve the efficiency and accuracy of testers during API or function testing.

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