In Java, the programmer can specify expected exceptions for JUnit test cases like this:
@Test(expected = ArithmeticException.class)
public void omg()
{
int blackHole = 1 / 0;
}
How would I do this in Kotlin? I have tried two syntax variations, but none of them worked:
import org.junit.Test
// ...
@Test(expected = ArithmeticException) fun omg()
Please specify constructor invocation;
classifier 'ArithmeticException' does not have a companion object
@Test(expected = ArithmeticException.class) fun omg()
name expected ^
^ expected ')'
ベストアンサー1
The Kotlin translation of the Java example for JUnit 4.12 is:
@Test(expected = ArithmeticException::class)
fun omg() {
val blackHole = 1 / 0
}
However, JUnit 4.13 introduced two assertThrows methods for finer-granular exception scopes:
@Test
fun omg() {
// ...
assertThrows(ArithmeticException::class.java) {
val blackHole = 1 / 0
}
// ...
}
Both assertThrows methods return the expected exception for additional assertions:
@Test
fun omg() {
// ...
val exception = assertThrows(ArithmeticException::class.java) {
val blackHole = 1 / 0
}
assertEquals("/ by zero", exception.message)
// ...
}