How can one differentiate between "balāʾ" (calamity/trial) and "ibtilāʾ" (testing/trial)?

The word "balā’" (بلا, trial/affliction) is an antinym, used to mean both blessing and retribution, and also to mean testing. All these meanings have occurred in the Quran, such as in the verse: "a goodly trial" (balā’an ḥasanan), which refers to a blessing and a gift. And His saying: "a great trial" (balā’un ʿaẓīm), which refers to retribution. It could also mean a test. Likewise, His saying: "And We will surely test you until We make evident those who strive among you."