fn test_range_exhaustive()

in starlark/src/values/types/range.rs [310:344]

• 32 lines of code
• 9 McCabe index (conditional complexity)

    fn test_range_exhaustive() {
        // The range implementation is fairly hairy. Lots of corner cases etc.
        // Especially around equality, length.
        // Therefore, generate ranges exhaustively over a very small range
        // and test lots of properties about them.
        let mut ranges = Vec::with_capacity(294);
        for start in -3..4 {
            for stop in -3..4 {
                for step in -3..3 {
                    let step = if step >= 0 { step + 1 } else { step };
                    ranges.push(range(start, stop, step))
                }
            }
        }
        assert_eq!(ranges.len(), 294); // Assert we don't accidentally take too long

        let heap = Heap::new();
        for x in &ranges {
            let full: Vec<Value> = x.iterate(&heap).unwrap().collect();
            assert_eq!(x.length().unwrap(), full.len() as i32);
            for (i, v) in full.iter().enumerate() {
                assert_eq!(x.at(Value::new_int(i as i32), &heap).unwrap(), *v);
            }
        }

        // Takes 294^2 steps - but completes instantly
        for x in &ranges {
            for y in &ranges {
                assert_eq!(
                    x == y,
                    Iterator::eq(x.iterate(&heap).unwrap(), y.iterate(&heap).unwrap())
                )
            }
        }
    }