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Source file src/pkg/big/rat_test.go

// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package big

import "testing"


type setStringTest struct {
    in, out string
    ok      bool
}

var setStringTests = []setStringTest{
    setStringTest{"0", "0", true},
    setStringTest{"-0", "0", true},
    setStringTest{"1", "1", true},
    setStringTest{"-1", "-1", true},
    setStringTest{"1.", "1", true},
    setStringTest{"1e0", "1", true},
    setStringTest{"1.e1", "10", true},
    setStringTest{in: "1e", ok: false},
    setStringTest{in: "1.e", ok: false},
    setStringTest{in: "1e+14e-5", ok: false},
    setStringTest{in: "1e4.5", ok: false},
    setStringTest{in: "r", ok: false},
    setStringTest{in: "a/b", ok: false},
    setStringTest{in: "a.b", ok: false},
    setStringTest{"-0.1", "-1/10", true},
    setStringTest{"-.1", "-1/10", true},
    setStringTest{"2/4", "1/2", true},
    setStringTest{".25", "1/4", true},
    setStringTest{"-1/5", "-1/5", true},
    setStringTest{"8129567.7690E14", "812956776900000000000", true},
    setStringTest{"78189e+4", "781890000", true},
    setStringTest{"553019.8935e+8", "55301989350000", true},
    setStringTest{"98765432109876543210987654321e-10", "98765432109876543210987654321/10000000000", true},
    setStringTest{"9877861857500000E-7", "3951144743/4", true},
    setStringTest{"2169378.417e-3", "2169378417/1000000", true},
    setStringTest{"884243222337379604041632732738665534", "884243222337379604041632732738665534", true},
    setStringTest{"53/70893980658822810696", "53/70893980658822810696", true},
    setStringTest{"106/141787961317645621392", "53/70893980658822810696", true},
    setStringTest{"204211327800791583.81095", "4084226556015831676219/20000", true},
}

func TestRatSetString(t *testing.T) {
    for i, test := range setStringTests {
        x, ok := new(Rat).SetString(test.in)

        if ok != test.ok || ok && x.String() != test.out {
            t.Errorf("#%d got %s want %s", i, x.String(), test.out)
        }
    }
}


type floatStringTest struct {
    in   string
    prec int
    out  string
}

var floatStringTests = []floatStringTest{
    floatStringTest{"0", 0, "0"},
    floatStringTest{"0", 4, "0"},
    floatStringTest{"1", 0, "1"},
    floatStringTest{"1", 2, "1"},
    floatStringTest{"-1", 0, "-1"},
    floatStringTest{".25", 2, "0.25"},
    floatStringTest{".25", 1, "0.3"},
    floatStringTest{"-1/3", 3, "-0.333"},
    floatStringTest{"-2/3", 4, "-0.6667"},
}

func TestFloatString(t *testing.T) {
    for i, test := range floatStringTests {
        x, _ := new(Rat).SetString(test.in)

        if x.FloatString(test.prec) != test.out {
            t.Errorf("#%d got %s want %s", i, x.FloatString(test.prec), test.out)
        }
    }
}


func TestRatSign(t *testing.T) {
    zero := NewRat(0, 1)
    for _, a := range setStringTests {
        var x Rat
        x.SetString(a.in)
        s := x.Sign()
        e := x.Cmp(zero)
        if s != e {
            t.Errorf("got %d; want %d for z = %v", s, e, &x)
        }
    }
}


type ratCmpTest struct {
    rat1, rat2 string
    out        int
}

var ratCmpTests = []ratCmpTest{
    ratCmpTest{"0", "0/1", 0},
    ratCmpTest{"1/1", "1", 0},
    ratCmpTest{"-1", "-2/2", 0},
    ratCmpTest{"1", "0", 1},
    ratCmpTest{"0/1", "1/1", -1},
    ratCmpTest{"-5/1434770811533343057144", "-5/1434770811533343057145", -1},
    ratCmpTest{"49832350382626108453/8964749413", "49832350382626108454/8964749413", -1},
    ratCmpTest{"-37414950961700930/7204075375675961", "37414950961700930/7204075375675961", -1},
    ratCmpTest{"37414950961700930/7204075375675961", "74829901923401860/14408150751351922", 0},
}

func TestRatCmp(t *testing.T) {
    for i, test := range ratCmpTests {
        x, _ := new(Rat).SetString(test.rat1)
        y, _ := new(Rat).SetString(test.rat2)

        out := x.Cmp(y)
        if out != test.out {
            t.Errorf("#%d got out = %v; want %v", i, out, test.out)
        }
    }
}


func TestIsInt(t *testing.T) {
    one := NewInt(1)
    for _, a := range setStringTests {
        var x Rat
        x.SetString(a.in)
        i := x.IsInt()
        e := x.Denom().Cmp(one) == 0
        if i != e {
            t.Errorf("got %v; want %v for z = %v", i, e, &x)
        }
    }
}


func TestRatAbs(t *testing.T) {
    zero := NewRat(0, 1)
    for _, a := range setStringTests {
        var z Rat
        z.SetString(a.in)
        var e Rat
        e.Set(&z)
        if e.Cmp(zero) < 0 {
            e.Sub(zero, &e)
        }
        z.Abs(&z)
        if z.Cmp(&e) != 0 {
            t.Errorf("got z = %v; want %v", &z, &e)
        }
    }
}


type ratBinFun func(z, x, y *Rat) *Rat
type ratBinArg struct {
    x, y, z string
}

func testRatBin(t *testing.T, i int, name string, f ratBinFun, a ratBinArg) {
    x, _ := NewRat(0, 1).SetString(a.x)
    y, _ := NewRat(0, 1).SetString(a.y)
    z, _ := NewRat(0, 1).SetString(a.z)
    out := f(NewRat(0, 1), x, y)

    if out.Cmp(z) != 0 {
        t.Errorf("%s #%d got %s want %s", name, i, out, z)
    }
}


type ratBinTest struct {
    x, y      string
    sum, prod string
}

var ratBinTests = []ratBinTest{
    ratBinTest{"0", "0", "0", "0"},
    ratBinTest{"0", "1", "1", "0"},
    ratBinTest{"-1", "0", "-1", "0"},
    ratBinTest{"-1", "1", "0", "-1"},
    ratBinTest{"1", "1", "2", "1"},
    ratBinTest{"1/2", "1/2", "1", "1/4"},
    ratBinTest{"1/4", "1/3", "7/12", "1/12"},
    ratBinTest{"2/5", "-14/3", "-64/15", "-28/15"},
    ratBinTest{"4707/49292519774798173060", "-3367/70976135186689855734", "84058377121001851123459/1749296273614329067191168098769082663020", "-1760941/388732505247628681598037355282018369560"},
    ratBinTest{"-61204110018146728334/3", "-31052192278051565633/2", "-215564796870448153567/6", "950260896245257153059642991192710872711/3"},
    ratBinTest{"-854857841473707320655/4237645934602118692642972629634714039", "-18/31750379913563777419", "-27/133467566250814981", "15387441146526731771790/134546868362786310073779084329032722548987800600710485341"},
    ratBinTest{"618575745270541348005638912139/19198433543745179392300736", "-19948846211000086/637313996471", "27674141753240653/30123979153216", "-6169936206128396568797607742807090270137721977/6117715203873571641674006593837351328"},
    ratBinTest{"-3/26206484091896184128", "5/2848423294177090248", "15310893822118706237/9330894968229805033368778458685147968", "-5/24882386581946146755650075889827061248"},
    ratBinTest{"26946729/330400702820", "41563965/225583428284", "1238218672302860271/4658307703098666660055", "224002580204097/14906584649915733312176"},
    ratBinTest{"-8259900599013409474/7", "-84829337473700364773/56707961321161574960", "-468402123685491748914621885145127724451/396955729248131024720", "350340947706464153265156004876107029701/198477864624065512360"},
    ratBinTest{"575775209696864/1320203974639986246357", "29/712593081308", "410331716733912717985762465/940768218243776489278275419794956", "808/45524274987585732633"},
    ratBinTest{"1786597389946320496771/2066653520653241", "6269770/1992362624741777", "3559549865190272133656109052308126637/4117523232840525481453983149257", "8967230/3296219033"},
    ratBinTest{"-36459180403360509753/32150500941194292113930", "9381566963714/9633539", "301622077145533298008420642898530153/309723104686531919656937098270", "-3784609207827/3426986245"},
}

func TestRatBin(t *testing.T) {
    for i, test := range ratBinTests {
        arg := ratBinArg{test.x, test.y, test.sum}
        testRatBin(t, i, "Add", (*Rat).Add, arg)

        arg = ratBinArg{test.y, test.x, test.sum}
        testRatBin(t, i, "Add symmetric", (*Rat).Add, arg)

        arg = ratBinArg{test.sum, test.x, test.y}
        testRatBin(t, i, "Sub", (*Rat).Sub, arg)

        arg = ratBinArg{test.sum, test.y, test.x}
        testRatBin(t, i, "Sub symmetric", (*Rat).Sub, arg)

        arg = ratBinArg{test.x, test.y, test.prod}
        testRatBin(t, i, "Mul", (*Rat).Mul, arg)

        arg = ratBinArg{test.y, test.x, test.prod}
        testRatBin(t, i, "Mul symmetric", (*Rat).Mul, arg)

        if test.x != "0" {
            arg = ratBinArg{test.prod, test.x, test.y}
            testRatBin(t, i, "Quo", (*Rat).Quo, arg)
        }

        if test.y != "0" {
            arg = ratBinArg{test.prod, test.y, test.x}
            testRatBin(t, i, "Quo symmetric", (*Rat).Quo, arg)
        }
    }
}


func TestIssue820(t *testing.T) {
    x := NewRat(3, 1)
    y := NewRat(2, 1)
    z := y.Quo(x, y)
    q := NewRat(3, 2)
    if z.Cmp(q) != 0 {
        t.Errorf("got %s want %s", z, q)
    }

    y = NewRat(3, 1)
    x = NewRat(2, 1)
    z = y.Quo(x, y)
    q = NewRat(2, 3)
    if z.Cmp(q) != 0 {
        t.Errorf("got %s want %s", z, q)
    }

    x = NewRat(3, 1)
    z = x.Quo(x, x)
    q = NewRat(3, 3)
    if z.Cmp(q) != 0 {
        t.Errorf("got %s want %s", z, q)
    }
}