tvl-depot/users/sterni/nix/int/tests/default.nix

{ depot, lib, ... }:

let

  inherit (depot.nix.runTestsuite)
    runTestsuite
    it
    assertEq
    ;

  inherit (depot.users.sterni.nix)
    int
    string
    fun
    flow
    ;

  testBounds = it "checks minBound and maxBound" [
    # this is gonna blow up in my face because
    # integer overflow is undefined behavior in
    # C++, so most likely anything could happen?
    (assertEq "maxBound is the maxBound" true
      (int.maxBound + 1 < int.maxBound))
    (assertEq "minBound is the minBound" true
      (int.minBound - 1 > int.minBound))
    (assertEq "maxBound overflows to minBound"
      (int.maxBound + 1)
      int.minBound)
    (assertEq "minBound overflows to maxBound"
      (int.minBound - 1)
      int.maxBound)
  ];

  expectedBytes = [
    "00" "01" "02" "03" "04" "05" "06" "07" "08" "09" "0A" "0B" "0C" "0D" "0E" "0F"
    "10" "11" "12" "13" "14" "15" "16" "17" "18" "19" "1A" "1B" "1C" "1D" "1E" "1F"
    "20" "21" "22" "23" "24" "25" "26" "27" "28" "29" "2A" "2B" "2C" "2D" "2E" "2F"
    "30" "31" "32" "33" "34" "35" "36" "37" "38" "39" "3A" "3B" "3C" "3D" "3E" "3F"
    "40" "41" "42" "43" "44" "45" "46" "47" "48" "49" "4A" "4B" "4C" "4D" "4E" "4F"
    "50" "51" "52" "53" "54" "55" "56" "57" "58" "59" "5A" "5B" "5C" "5D" "5E" "5F"
    "60" "61" "62" "63" "64" "65" "66" "67" "68" "69" "6A" "6B" "6C" "6D" "6E" "6F"
    "70" "71" "72" "73" "74" "75" "76" "77" "78" "79" "7A" "7B" "7C" "7D" "7E" "7F"
    "80" "81" "82" "83" "84" "85" "86" "87" "88" "89" "8A" "8B" "8C" "8D" "8E" "8F"
    "90" "91" "92" "93" "94" "95" "96" "97" "98" "99" "9A" "9B" "9C" "9D" "9E" "9F"
    "A0" "A1" "A2" "A3" "A4" "A5" "A6" "A7" "A8" "A9" "AA" "AB" "AC" "AD" "AE" "AF"
    "B0" "B1" "B2" "B3" "B4" "B5" "B6" "B7" "B8" "B9" "BA" "BB" "BC" "BD" "BE" "BF"
    "C0" "C1" "C2" "C3" "C4" "C5" "C6" "C7" "C8" "C9" "CA" "CB" "CC" "CD" "CE" "CF"
    "D0" "D1" "D2" "D3" "D4" "D5" "D6" "D7" "D8" "D9" "DA" "DB" "DC" "DD" "DE" "DF"
    "E0" "E1" "E2" "E3" "E4" "E5" "E6" "E7" "E8" "E9" "EA" "EB" "EC" "ED" "EE" "EF"
    "F0" "F1" "F2" "F3" "F4" "F5" "F6" "F7" "F8" "F9" "FA" "FB" "FC" "FD" "FE" "FF"
  ];

  hexByte = i: string.fit { width = 2; char = "0"; } (int.toHex i);

  hexInts = [
    { left = 0; right = "0"; }
    { left = 1; right = "1"; }
    { left = 11; right = "B"; }
    { left = 123; right = "7B"; }
    { left = 9000; right = "2328"; }
    { left = 2323; right = "913"; }
    { left = 4096; right = "1000"; }
    { left = int.maxBound; right = "7FFFFFFFFFFFFFFF"; }
    { left = int.minBound; right = "-8000000000000000"; }
  ];

  testHex = it "checks conversion to hex" (lib.flatten [
    (lib.imap0 (i: hex: [
      (assertEq "hexByte ${toString i} == ${hex}" (hexByte i) hex)
      (assertEq "${toString i} == fromHex ${hex}" i (int.fromHex hex))
    ]) expectedBytes)
    (builtins.map ({ left, right }: [
      (assertEq "toHex ${toString left} == ${right}" (int.toHex left) right)
      (assertEq "${toString left} == fromHex ${right}" left (int.fromHex right))
    ]) hexInts)
  ]);

  testBasic = it "checks basic int operations" [
    (assertEq "122 is even" (int.even 122 && !(int.odd 122)) true)
    (assertEq "123 is odd" (int.odd 123 && !(int.even 123)) true)
    (assertEq "abs -4959" (int.abs (-4959)) 4959)
  ];

  expNumbers = [
    { left = -3; right = 0.125; }
    { left = -2; right = 0.25; }
    { left = -1; right = 0.5; }
    { left = 0; right = 1; }
    { left = 1; right = 2; }
    { left = 2; right = 4; }
    { left = 3; right = 8; }
    { left = 4; right = 16; }
    { left = 5; right = 32; }
    { left = 16; right = 65536; }
  ];

  testExp = it "checks exponentiation"
    (builtins.map ({ left, right }:
      assertEq
        "2 ^ ${toString left} == ${toString right}"
        (int.exp 2 left) right) expNumbers);

  shifts = [
    { a =   2; b = 5; c =   64; op = "<<"; }
    { a =  -2; b = 5; c =  -64; op = "<<"; }
    { a = 123; b = 4; c = 1968; op = "<<"; }
    { a =   1; b = 8; c =  256; op = "<<"; }
    { a = 256; b = 8; c =    1; op = ">>"; }
    { a = 374; b = 2; c =   93; op = ">>"; }
    { a =   2; b = 2; c =    0; op = ">>"; }
    { a =  99; b = 9; c =    0; op = ">>"; }
  ];

  checkShift = { a, b, c, op }@args:
    let
      f = flow.match op {
        "<<" = int.bitShiftL;
        ">>" = int.bitShiftR;
      };
    in assertEq "${toString a} ${op} ${toString b} == ${toString c}" (f a b) c;

  checkShiftRDivExp = n:
    assertEq "${toString n} >> 5 == ${toString n} / 2 ^ 5"
      (int.bitShiftR n 5) (int.div n (int.exp 2 5));

  checkShiftLMulExp = n:
    assertEq "${toString n} >> 6 == ${toString n} * 2 ^ 6"
      (int.bitShiftL n 5) (int.mul n (int.exp 2 5));

  testBit = it "checks bitwise operations" (lib.flatten [
    (builtins.map checkShift shifts)
    (builtins.map checkShiftRDivExp [
      1
      2
      3
      5
      7
      23
      1623
      238
      34
      348
      2834
      834
      348
    ])
    (builtins.map checkShiftLMulExp [
      1
      2
      3
      5
      7
      23
      384
      3
      2
      5991
      85109
      38
    ])
  ]);

  divisions = [
    { a =  2; b =  1; c = 2; mod = 0;}
    { a =  2; b =  2; c = 1; mod = 0;}
    { a = 20; b = 10; c = 2; mod = 0;}
    { a = 12; b =  5; c = 2; mod = 2;}
    { a = 23; b =  4; c = 5; mod = 3;}
  ];

  checkDiv = n: { a, b, c, mod }: [
    (assertEq "${n}: div result" (int.div a b) c)
    (assertEq "${n}: mod result" (int.mod a b) mod)
    (assertEq "${n}: divMod law" ((int.div a b) * b + (int.mod a b)) a)
  ];

  testDivMod = it "checks integer division and modulo"
    (lib.flatten [
      (builtins.map (checkDiv "+a / +b") divisions)
      (builtins.map (fun.rl (checkDiv "-a / +b") (x: x // {
        a = -x.a;
        c = -x.c;
        mod = -x.mod;
      })) divisions)
      (builtins.map (fun.rl (checkDiv "+a / -b") (x: x // {
        b = -x.b;
        c = -x.c;
      })) divisions)
      (builtins.map (fun.rl (checkDiv "-a / -b") (x: x // {
        a = -x.a;
        b = -x.b;
        mod = -x.mod;
      })) divisions)
    ]);

in
  runTestsuite "nix.int" [
    testBounds
    testHex
    testBasic
    testExp
    testBit
    testDivMod
  ]