Let NullAway handle assertions in test code

Author: marcphilipp

gradle/plugins/common/src/main/kotlin/junitbuild.java-nullability-conventions.gradle.kts

@@ -1,6 +1,7 @@
 import junitbuild.extensions.dependencyFromLibs
 import junitbuild.extensions.javaModuleName
 import net.ltgt.gradle.errorprone.errorprone
+import net.ltgt.gradle.nullaway.nullaway
 
 plugins {
 	`java-library`
@@ -23,3 +24,9 @@ tasks.withType<JavaCompile>().configureEach {
 		enable("NullAway")
 	}
 }
+
+tasks.compileTestJava {
+	options.errorprone.nullaway {
+		handleTestAssertionLibraries = true
+	}
+}