Exercism: Go version of the 'Triangle' exercise.
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package triangle
import (
"math"
"testing"
)
const targetTestVersion = 2
type testCase struct {
want Kind
a, b, c float64
}
// basic test cases
var testData = []testCase{
{Equ, 2, 2, 2}, // same length
{Equ, 10, 10, 10}, // a little bigger
{Iso, 3, 4, 4}, // last two sides equal
{Iso, 4, 3, 4}, // first and last sides equal
{Iso, 4, 4, 3}, // first two sides equal
{Iso, 10, 10, 2}, // again
{Iso, 2, 4, 2}, // a "triangle" that is just a line is still OK
{Sca, 3, 4, 5}, // no sides equal
{Sca, 10, 11, 12}, // again
{Sca, 5, 4, 2}, // descending order
{Sca, .4, .6, .3}, // small sides
{Sca, 1, 4, 3}, // a "triangle" that is just a line is still OK
{NaT, 0, 0, 0}, // zero length
{NaT, 3, 4, -5}, // negative length
{NaT, 1, 1, 3}, // fails triangle inequality
{NaT, 2, 5, 2}, // another
{NaT, 7, 3, 2}, // another
}
// generate cases with NaN and Infs, append to basic cases
func init() {
nan := math.NaN()
pinf := math.Inf(1)
ninf := math.Inf(-1)
nf := make([]testCase, 4*4*4)
i := 0
for _, a := range []float64{3, nan, pinf, ninf} {
for _, b := range []float64{4, nan, pinf, ninf} {
for _, c := range []float64{5, nan, pinf, ninf} {
nf[i] = testCase{NaT, a, b, c}
i++
}
}
}
testData = append(testData, nf[1:]...)
}
// Test that the kinds are not equal to each other.
// If they are equal, then TestKind will return false positives.
func TestKindsNotEqual(t *testing.T) {
kindsAndNames := []struct {
kind Kind
name string
}{
{Equ, "Equ"},
{Iso, "Iso"},
{Sca, "Sca"},
{NaT, "NaT"},
}
for i, pair1 := range kindsAndNames {
for j := i + 1; j < len(kindsAndNames); j++ {
pair2 := kindsAndNames[j]
if pair1.kind == pair2.kind {
t.Fatalf("%s should not be equal to %s", pair1.name, pair2.name)
}
}
}
}
func TestKind(t *testing.T) {
for _, test := range testData {
got := KindFromSides(test.a, test.b, test.c)
if got != test.want {
t.Fatalf("Triangle with sides, %g, %g, %g = %v, want %v",
test.a, test.b, test.c, got, test.want)
}
}
}
func TestTestVersion(t *testing.T) {
if testVersion != targetTestVersion {
t.Fatalf("Found testVersion = %v, want %v", testVersion, targetTestVersion)
}
}
func BenchmarkKind(b *testing.B) {
for i := 0; i < b.N; i++ {
for _, test := range testData {
KindFromSides(test.a, test.b, test.c)
}
}
}