MissingMethodException when using Groovy and JUnit 5 Assertions - groovy

Question

Trying to use JUnit 5 class Assertions, specifically assertAll() with Groovy.
Basic Java proves the following syntax:
#Test
public void someTest() {
assertAll('heading',
() -> assertTrue(firstName),
() -> assertTrue(lastName)
);
}
Since I'm stuck to Groovy v2.4, which does not support lambdas, what I do looks like (tried several options, however all of those provide the same error):
#Test
void 'Some test'() {
assertAll('heading',
{ -> assert firstName },
{ -> assert lastName }
)
}
Error message:
groovy.lang.MissingMethodException:
No signature of method: static org.junit.jupiter.api.Assertions.assertAll() is applicable for argument
types: (path.GeneralTests$_Some_test_closure10...)
values: [path.GeneralTests$_Some_test_losure10#1ef13eab, ...]
Looks like the problem is with assertAll() method itself, exception is quite obvious, however that's quite a challenge to get the possible solution, since I had to switch to Groovy from Python just recently.
Indeed, I am going to take some courses with Groovy in future, but you know, you always have to provide results for yesterday.
Would highly appreciate your suggestions!

Answer 1

In this particular case, you need to cast Groovy closure to org.junit.jupiter.api.function.Executable interface explicitly:
import org.junit.jupiter.api.Test
import org.junit.jupiter.api.function.Executable
import static org.junit.jupiter.api.Assertions.*
class Test {
#Test
void 'Some test'() {
assertAll('heading',
{ assertTrue(true) } as Executable,
{ assertFalse(false) } as Executable)
}
}