Your check constraint definitions are incomplete
If you reformat your statement you can easily see it:
Code:
CREATE TABLE test
(
test_date DATE,
test_time DATE,
test_result CHAR (4) CONSTRAINT ck_test_result CHECK ???,
Reason_failed VARCHAR2 (19) CONSTRAINT ck_reason_failed CHECK ???,
CONSTRAINT test_pk PRIMARY KEY (test_date, test_time)
);
Instead of the
??? you need some kind of expression that defines the check constraint.