java-test-updater

Java Test Updater

Overview

Automatically update Java test code to align with changes in production code, ensuring tests compile and pass after refactoring, signature changes, or behavior modifications.

Workflow

1. Analyze Code Changes

Compare old and new versions of the production code to identify changes:

Read both versions:

• Old code version (before changes)
• New code version (after changes)
• Identify the specific class and methods that changed

Categorize changes:

• Signature changes: Parameter types, parameter order, return type, method name
• Refactoring: Class renamed, method moved, package changed
• Behavior changes: Logic modified, new exceptions, different return values
• API changes: New methods added, old methods removed

Example change analysis:

// Old version
public double calculateDiscount(double price) {
    return price * 0.1;
}

// New version
public double calculateDiscount(double price, double discountRate) {
    if (discountRate < 0 || discountRate > 1) {
        throw new IllegalArgumentException("Invalid discount rate");
    }
    return price * discountRate;
}

Identified changes:

• Added parameter: discountRate
• Added validation with exception
• Changed calculation logic

2. Analyze Existing Tests

Read and understand the old test code:

Identify test structure:

• Test class name and package
• Test methods and their purposes
• Setup and teardown methods (@Before, @BeforeEach, @After, @AfterEach)
• Test data and fixtures
• Mocks and stubs used

Map tests to code changes:

• Which tests call the changed methods
• Which assertions depend on changed behavior
• Which mocks need updating

Example old test:

@Test
public void testCalculateDiscount() {
    double price = 100.0;
    double result = calculator.calculateDiscount(price);
    assertEquals(10.0, result, 0.01);
}

3. Update Method Calls

Modify test code to match new method signatures: