Object FANATICS assertion library [asserting the weaving device] framework in the Java class library detailed explanation
Object FANATICS assertion library [asserting the weaving device] framework in the Java class library detailed explanation
introduction:
In the process of software development, testing is a very important part.It is a powerful test tool that allows us to insert the verification logic of the expected results in the code to help us quickly discover and repair the bug.Object Fanatics is an open source Java assertion library. It provides the function of asserting the weaving machine. By injecting the logic of the assertion during runtime, we can assert without modifying the original code.
1. Ecclail the role of the weaving machine
Once the knitting machine is an AOP (facing cut -faced programming) technology.Its main function is to dynamically insert the preset assertion logic before or after the target method is executed.In this way, we can interact with the target method, obtain its input parameters and return results, and assertive verification.The assertion of the weaving machine can help us effectively perform unit testing and integration testing to improve the quality and reliability of code.
2. Design principle of Object Fanatics framework
Object Fanatics is based on the Java bytecode operation technology and realizes the assertion of the weaving machine by dynamically generating proxy categories.It uses an entry point expression similar to ASPECTJ to specify the target method that needs to be asserted.When running, Object Fanatics will use the byte code operation library (such as ASM) to modify the byte code of the target class and insert the logic of the assertion.This method not only guarantees performance, but also avoids the trouble of modifying the source code and potential risks.
3. Use Object Fanatics to assert
The following is a simple example, showing how to use Object Fanatics to asserts:
import com.objectfanatics.asserts.Assertion;
import com.objectfanatics.asserts.util.ObjectFanatics;
public class Calculator {
public int add(int a, int b) {
return a + b;
}
public static void main(String[] args) {
Calculator calculator = new Calculator();
Assertion assertion = ObjectFanatics.createAssertion(calculator);
// Add assertion logic
assertion
.when ("add (int, int)") // Specify the target method
.withparameters (2, 3) // Set the method parameter
.thenreturn (5); // Set the expected return value
// Execute the target method
int result = calculator.add(2, 3);
// Verification assertion
assertion.verify();
System.out.println("Result: " + result);
}
}
In the above example, we created a Calculator class and used Object Fanatics to create an ASSERTION object.Then, we use the `when ()" method to specify the target method `add (int, int)`, and set the input parameter of the method using the `Withparameters ()`.Then, we set the expected return value with the `Thenreturn ()`.Finally, we execute the target method and use the `verify ()` method to verify the assertion results.If the assertion passes, the program will calculate the result; otherwise, the Assertionerror will be thrown.
4. Summary
Object Fanatics asserts that the library provides a convenient and powerful assertion of the weaving framework, which can be widely used in unit testing and integrated tests in the Java class library.Its technical principles are based on bytecode operation and AOO and the idea of proxy by dynamically generating proxy classes.Through the Object Fanatics, we can easily insert and verify the logic of assertions to improve the reliability and quality of the code.
Note: The above code examples are only used as demo purposes. In the actual code, more assertions and abnormal processing may be needed.
