Test for null to primitive cast in ArgumentsAccessor

Issue: #1370

Author: sbrannen

junit-jupiter-params/src/test/java/org/junit/jupiter/params/aggregator/ArgumentsAccessorTests.java

@@ -66,6 +66,11 @@ void getWithCastToPrimitiveType() {
 			() -> new DefaultArgumentsAccessor(1).get(0, int.class));
 		assertThat(exception.getMessage()).isEqualTo(
 			"Argument at index [0] with value [1] and type [java.lang.Integer] could not be converted or cast to type [int].");
+
+		exception = assertThrows(ArgumentsAccessorException.class,
+			() -> new DefaultArgumentsAccessor(new Object[] { null }).get(0, int.class));
+		assertThat(exception.getMessage()).isEqualTo(
+			"Argument at index [0] with value [null] and type [null] could not be converted or cast to type [int].");
 	}
 
 	@Test