JMOCK framework technical principle explore and Java class library application
JMOCK framework technical principle explore and Java class library application
I. Introduction
During the software development process, unit testing is a very important link.By testing the units of each functional module, the problems in the code can be effectively discovered and fixed, thereby improving the quality and stability of the software.However, when testing, we often need to simulate a rich test environment and various test scenarios to ensure the comprehensiveness and reliability of the unit test.The JMock framework is a Java class library specifically used to solve such problems.
2. The principles and characteristics of the JMock framework
JMock is a test framework based on simulation and behavior -driven development.Its core principle is to replace real objects by creating analog objects in order to better control the test environment and verify test results.Compared with other testing frameworks, JMock's uniqueness is its powerful matching (Matcher) and Beilt-in Chaining function.
1. Matcher
In JMOCK, the matcher is used to verify whether the input parameters and the return results meet our expectations.By using the matching device, we can describe the expected input and output conditions more concisely and accurately.For example, using jmock's `Equalto` matcher can determine whether the two objects are equal. Using the` Startswith` matcher can determine whether a string starts with a specified prefix.
2. Beautt-in Chaining
JMock provides a rich built -in behavioral chain display function, allowing us to more intuitively describe and verify the execution order and number of a certain operation.By using keywords such as `Oneof`,` Exactly` provided by JMOCK, we can clearly express the interaction process and expected behavior of the object in the test case.In this way, we can not only write test code more easily, but also better understand and maintain test cases.
Third, example of the JMock framework
The use of the JMock framework is displayed by a simple example.
Suppose we have a calculator class called `Calculator`, and one of the` add` methods is used to find two integers.We need to test this method now to ensure that its functions are correct.
First, we need to create an analog object to replace the `Calculator` class.We can use the `Mockey` class provided by JMOCK to create a context environment for an analog object.code show as below:
import org.jmock.Expectations;
import org.jmock.Mockery;
import org.junit.Test;
public class CalculatorTest {
@Test
public void testAdd() {
Mockery context = new Mockery();
final Calculator mockCalculator = context.mock(Calculator.class);
// Set the expected behavior
context.checking(new Expectations() {{
oneOf(mockCalculator).add(2, 3);
will(returnValue(5));
}});
CalculatorTestHelper helper = new CalculatorTestHelper(mockCalculator);
int result = helper.add(2, 3);
assertEquals(5, result);
context.assertIsSatisfied();
}
}
In the above code, we first created a context environment for the simulation object as an analog object.Then, we created a simulated `Calculator` object` mockcalculator` by calling the `Context.mock` method.Then, we set a desired behavior using the `Context.chcking` method, that is, when calling the` add (2, 3) "method, the return value is 5.Finally, we called the method of `Helper.add (2, 3)` to test, and use the `Asseretequals` method to verify whether the return value meets the expectations.
It should be noted that when using the JMock framework, we need to call the final call of the test method `context.assertisatisFied ()` to verify whether all expectations are satisfied.
Fourth, summary
Through the inquiry of this article, we understand the principles and characteristics of the JMock framework, and demonstrate its usage method through a simple example.The powerful matchmaker and behavioral chain display function of the JMock framework make the unit test simpler and intuitive.In the actual software development process, we can use the JMock framework to build a more comprehensive and reliable unit test to improve the quality and maintenance of code.
references:
1. JMock Documentation: http://jmock.org/
2. JMock GitHub Repository: https://github.com/jmock-developers/jmock-library
