# coverage.ludic — a spec built to be measured by `bin/x test --coverage` (issue
# #45). Compiled with `--coverage`, every statement bumps a per-source-line hit
# counter; at exit the counts are dumped and `bin/x test --coverage` turns them
# into a per-file line-coverage report.
#
# The tests below exercise `sign` fully but only the taken branches of `grade`,
# so the report flags `grade`'s unreached line — the whole point of coverage:
# it shows you the branch your tests forgot.
#
# As an ordinary spec it still passes and prints:
#   == 3 passed, 0 failed ==
program CoverageSpec {
  # fully covered: the tests below hit all three returns.
  function sign(n: int) -> int {
    if n > 0 {
      return 1
    }
    if n < 0 {
      return 0 - 1
    }
    return 0
  }

  # partially covered: no test passes a score below 60, so the `return 0` (fail)
  # line is never reached and shows up as uncovered in the report.
  function grade(score: int) -> int {
    if score >= 90 {
      return 4
    }
    if score >= 60 {
      return 2
    }
    return 0
  }

  test "sign covers every branch" {
    expect_eq(sign(7), 1)
    expect_eq(sign(0 - 3), 0 - 1)
    expect_eq(sign(0), 0)
  }

  test "grade: high scores" {
    expect_eq(grade(95), 4)
    expect_eq(grade(75), 2)
  }

  test "grade: boundary" {
    expect_eq(grade(90), 4)
    expect_eq(grade(60), 2)
  }
}