// Test the `abs` function.
#test(calc.abs(-3), 3)
#test(calc.abs(3), 3)
#test(calc.abs(-0.0), 0.0)
#test(calc.abs(0.0), -0.0)
#test(calc.abs(-3.14), 3.14)
#test(calc.abs(50%), 50%)
#test(calc.abs(-25%), 25%)