JUnit assertFalse(false) can't find BooleanSupplier

Question

I am attempting to test an library I am designing using JUnit5. I have come to the point where I need to assert something is false however Gradle is running into errors whenever I attempt to use assertFalse(...).

I am using JUnit 5.2 with Gradle 5.1.1 and have tried the assertFalse() method signatures that fit my needs to no avail. This includes just with a boolean condition, with a condition plus a message, using Assertions.assertFalse(...) to remove the static import, etc.

I have been able to narrow down the code to just a simple test. The code below fails:

@Test
void test(){
    assertFalse(false);
}

My imports are:

import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;

//plus some others from the library

Gradle gives an error of:

ProjectDir/FTC_Robot_API/TeamCode
/src/test/java/org/firstinspires/ftc/teamcode/FTC_Library/Robot
/RobotBaseTest.java:28: error: cannot access BooleanSupplier
        assertFalse(false);
        ^
  class file for java.util.function.BooleanSupplier not found
1 error

It is my hope that what is obviously a boolean (false) is not a BooleanSupplier so I am stuck with regards to why it is giving me this error. Any help is appreciated

Answer 1

I had the same issue when using IntelliJ. To resolve it

1. Remove IntelliJ project files (e.g. .iml and .idea files)
2. Close the project
3. From the IntelliJ Welcome Screen select "Import Project"

4. Select "Project from Existing Sources"
5. Follow the prompts to set up the project. For more see the IntelliJ website: jetbrains.com/help/idea/import-project-or-module-wizard.html