How to create parameterized hooks in junit 5? - kotlin

Question

I am writing a test in using junit 5 where I want to run a same test on different sets of data. To achieve that, I am using parameterization. Now a situation came in where I want to run something before each set. I want to implement that in #BeforeEach hook and after some research, I found that ParameterResolver implementation can be one of the solution for that. But with that, test is getting issues to get parameter in #BeforeEach hook.
Here I am adding my code. These are kotlin classes. One test class StringDataClientTest which extends StringDataTest in which I am adding test parameter and #beforeEach hook. Adding #ExtendWith with this class which is extending StringParameterResolver class.
StringDataClientTest:
import org.junit.jupiter.api.DisplayName
import org.junit.jupiter.api.TestInstance
import org.junit.jupiter.params.ParameterizedTest
import org.junit.jupiter.params.provider.MethodSource
#TestInstance(TestInstance.Lifecycle.PER_CLASS)
class StringDataClientTest : StringDataTest() {
#DisplayName("First Client Test")
#ParameterizedTest
#MethodSource("getString")
fun firstClientTest(data: String) {
System.out.println("First client test for: $data")
}
}
StringDataTest:
import org.junit.jupiter.api.BeforeEach
import org.junit.jupiter.api.extension.ExtendWith
import org.junit.jupiter.params.provider.MethodSource
#ExtendWith(StringParameterResolver::class)
open class StringDataTest {
companion object {
#JvmStatic
fun getString(): List<String> {
return listOf(
"Parameter 1",
"Parameter 2",
"Parameter 3",
"Parameter 4"
)
}
}
#BeforeEach
#MethodSource("getString")
fun beforeEveryTest(value: String) {
System.out.println(" --------- Running before hook for: $value")
}
}
StringParameterResolver:
import org.junit.jupiter.api.extension.ExtensionContext
import org.junit.jupiter.api.extension.ParameterContext
import org.junit.jupiter.api.extension.ParameterResolver
class StringParameterResolver : ParameterResolver {
override fun supportsParameter(parameterContext: ParameterContext?, extensionContext: ExtensionContext?): Boolean {
return parameterContext!!.parameter.type === StringDataTest::class.java
}
override fun resolveParameter(parameterContext: ParameterContext?, extensionContext: ExtensionContext?): Any {
return StringDataTest()
}
}
And I am getting this exception in console output:
org.junit.jupiter.api.extension.ParameterResolutionException: No ParameterResolver registered for parameter [java.lang.String arg0] in method [public final void com.thescore.test.cases.team.testCode.StringDataTest.beforeEveryTest(java.lang.String)].
Expecting:
Running before hook for: Parameter 1
First client test for: Parameter 1
Running before hook for: Parameter 2
First client test for: Parameter 2
Running before hook for: Parameter 3
First client test for: Parameter 3
Running before hook for: Parameter 4
First client test for: Parameter 4
Haven't done parameterized hooks before. Please help with this. Thanks!