# Replace JUnit 4 Assumptions with JUnit Jupiter

# Description

This rule contributes to a stepwise transition to JUnit 5 by replacing the JUnit 4 assumption methods by the equivalent JUnit 5 ones. In JUnit 5, all methods used to carry out assumptions are declared in org.junit.jupiter.api.Assumptions (opens new window), while in JUnit 4 the equivalent methods are declared in org.junit.Assume (opens new window). This rule looks for invocations of overloaded methods of the JUnit 4 class Assume and replaces them with the invocations of equivalent overloaded alternatives declared in the JUnit 5 class Assumptions:

Assertions in Junit 4 `org.junit.Assume`	Assertions in JUnit 5 `org.junit.jupiter.api.Assumptions`
`Assume.assumeFalse` (opens new window)	`Assumptions.assumeFalse` (opens new window)
`Assume.assumeTrue` (opens new window)	`Assumptions.assumeTrue` (opens new window)

By replacing each of these JUnit 4 Assume methods by the corresponding Jupiter alternative, this rule promotes a stepwise transition to JUnit 5.

Requirements

This rule requires the following libraries to be present:

junit:junit:4.13
org.junit.jupiter:junit-jupiter-api:5.4.0

# Benefits

Migrates JUnit 4 tests to JUnit 5.

# Tags

# Code Changes

# Replacing Imports

Pre

import static org.junit.Assume.assumeTrue;
//...
public class OrderTest {
	//...
	@Test
	public void testService() {
		assumeTrue(orderService.isAvailableInStock("1", 5));
		Order order = orderService.book("1", 5, "user-id");
		assertNotNull(order);
	}
}

Post

import static org.junit.jupiter.api.Assumptions.assumeTrue;
//...
public class OrderTest {
	//...
	@Test
	public void testService() {
		assumeTrue(orderService.isAvailableInStock("1", 5));
		Order order = orderService.book("1", 5, "user-id");
		assertNotNull(order);
	}
}

# Replacing Invocations with a Message

Pre

import static org.junit.Assume.assumeTrue;
//...
public class OrderTest {
	//...
	@Test
	public void testService() {
		assumeTrue("If product 1 is available", orderService.isAvailableInStock("1", 5));
		Order order = orderService.book("1", 5, "user-id");
		assertNotNull(order);
	}
}

Post

import static org.junit.jupiter.api.Assumptions.assumeTrue;
//...
public class OrderTest {
	//...
	@Test
	public void testService() {
		assumeTrue(orderService.isAvailableInStock("1", 5), "If product 1 is available");
		Order order = orderService.book("1", 5, "user-id");
		assertNotNull(order);
	}
}

# Replacing the Assume Qualifier

Pre

import static org.assumeMethods.AssumeMethods.assumeTrue;
import org.junit.Assume;
//...
public class OrderTest {
	//...
	@Test
	public void testService() {
		Assume.assumeTrue(orderService.isAvailableInStock("1", 5));
		Order order = orderService.book("1", 5, "user-id");
		assertNotNull(order);
	}
}

Post

import static org.assumeMethods.AssumeMethods.assumeTrue;
import org.junit.jupiter.api.Assumptions;
//...
public class OrderTest {
	//...
	@Test
	public void testService() {
		Assumptions.assumeTrue(orderService.isAvailableInStock("1", 5));
		Order order = orderService.book("1", 5, "user-id");
		assertNotNull(order);
	}
}

🛠️ Auto-refactor Available

You can auto refactor this with jSparrow.
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# Properties

Property	Value
Rule ID	ReplaceJUnit4AssumptionsWithJupiter
First seen in jSparrow version	3.30.0
Minimum Java version	8
Remediation cost	2 min

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