Writing several tests together (multiple test cases)

This lesson covers running several test cases together in Julia, with the aim of understanding what a body of unit tests looks like.

Testing one function against several input patterns at once is called unit testing. Preparing a range of cases — ordinary values, boundary values, special values — finds bugs sooner.

The sample code gathers the cases into an array of tuples such as (2, 3, 5), passes each to add() with enumerate(test_cases), checks the result, and counts how many passed.

A common early stumble is testing only the ordinary cases and forgetting the boundaries (zero, negative numbers). Covering the cases that are easy to overlook is what matters.

Professional Julia development uses the standard Test module, but the underlying idea is exactly what you are learning here.

📖 Reference code

function add(a, b)
    a + b
end

test_cases = [(2, 3, 5), (-1, 1, 0), (0, 0, 0)]

passed = 0
for (i, tc) in enumerate(test_cases)
    a, b, expected = tc
    result = add(a, b)
    ok = result == expected
    if ok
        global passed += 1
    end
    println("Test $(i): $(ok ? "OK" : "NG")")
end
println("$(passed)/$(length(test_cases)) passed")

✍️ Your code

Type your code, then press "Run"

🧪 This site can't compile or run Julia directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).