test_approxratio = ->
  run_test [
    "approxratio(0.9054054)",
    "67/74",

    "approxratio(0.0102)",
    "1/98",

    "approxratio(0.518518)",
    "14/27",

    "approxratio(0.3333)",
    "1/3",

    "approxratio(0.5)",
    "1/2",

    "approxratio(3.14159)",
    "355/113",

    "approxratio(a*3.14)",
    "a*22/7",

    "approxratio(a*b)",
    "a*b",

    "approxratio((0.5*4)^(1/3))",
    "2^(1/3)",

    "approxratio(3.14)",
    "22/7",

    # see http://davidbau.com/archives/2010/03/14/the_mystery_of_355113.html
    "approxratio(3.14159)",
    "355/113",

    "approxratio(-3.14159)",
    "-355/113",

    "approxratio(0)",
    "0",

    "approxratio(0.0)",
    "0",

    "approxratio(2)",
    "2",

    "approxratio(2.0)",
    "2",

    # -------------------------------
    # checking some "long primes"
    # also called long period primes, or maximal period primes
    # i.e. those numbers whose reciprocal give
    # long repeating sequences
    # (long prime p gives repetition of p-1 digits).
    # big list here: https://oeis.org/A001913/b001913.txt
    # also see: https://oeis.org/A001913
    # -------------------------------

    # 1st long prime
    "approxratio(0.14)",
    "1/7",

    # 9th long prime, the biggest 2-digits long prime.
    # Often asked to
    # mental calculators to check their abilities.
    "approxratio(0.0103)",
    "1/97",

    # 60th long prime, the biggest 3-digits long prime.
    # Often asked to
    # mental calculators to check their abilities.
    "approxratio(0.001017)",
    "1/983",

    # 467th long prime, the biggest 4-digits long prime.
    "approxratio(0.00010033)",
    "1/9967",

    # 3617th long prime, the biggest 5-digits long prime.
    "approxratio(0.0000100011)",
    "1/99989",

    # 10000th long prime.
    "approxratio(0.00000323701)",
    "1/308927",

  ]