lnd/fn/slice_test.go
2024-07-10 15:34:57 -07:00

377 lines
7.4 KiB
Go

package fn
import (
"fmt"
"slices"
"testing"
"testing/quick"
"time"
"github.com/stretchr/testify/require"
)
func even(a int) bool { return a%2 == 0 }
func odd(a int) bool { return a%2 != 0 }
func TestAll(t *testing.T) {
x := []int{0, 2, 4, 6, 8}
require.True(t, All(even, x))
require.False(t, All(odd, x))
y := []int{1, 3, 5, 7, 9}
require.False(t, All(even, y))
require.True(t, All(odd, y))
z := []int{0, 2, 4, 6, 9}
require.False(t, All(even, z))
require.False(t, All(odd, z))
}
func TestAny(t *testing.T) {
x := []int{1, 3, 5, 7, 9}
require.False(t, Any(even, x))
require.True(t, Any(odd, x))
y := []int{0, 3, 5, 7, 9}
require.True(t, Any(even, y))
require.True(t, Any(odd, y))
z := []int{0, 2, 4, 6, 8}
require.True(t, Any(even, z))
require.False(t, Any(odd, z))
}
func TestMap(t *testing.T) {
inc := func(i int) int { return i + 1 }
x := []int{0, 2, 4, 6, 8}
y := Map(inc, x)
z := []int{1, 3, 5, 7, 9}
require.True(t, slices.Equal(y, z))
}
func TestFilter(t *testing.T) {
x := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
y := Filter(even, x)
require.True(t, All(even, y))
z := Filter(odd, y)
require.Zero(t, len(z))
}
func TestFoldl(t *testing.T) {
seed := []int{}
stupid := func(s []int, a int) []int { return append(s, a) }
x := []int{0, 1, 2, 3, 4}
r := Foldl(stupid, seed, x)
require.True(t, slices.Equal(x, r))
}
func TestFoldr(t *testing.T) {
seed := []int{}
stupid := func(a int, s []int) []int { return append(s, a) }
x := []int{0, 1, 2, 3, 4}
z := Foldr(stupid, seed, x)
slices.Reverse[[]int](x)
require.True(t, slices.Equal(x, z))
}
func TestFind(t *testing.T) {
x := []int{10, 11, 12, 13, 14, 15}
div3 := func(a int) bool { return a%3 == 0 }
div8 := func(a int) bool { return a%8 == 0 }
require.Equal(t, Find(div3, x), Some(12))
require.Equal(t, Find(div8, x), None[int]())
}
func TestFlatten(t *testing.T) {
x := [][]int{{0}, {1}, {2}}
y := Flatten(x)
require.True(t, slices.Equal(y, []int{0, 1, 2}))
}
func TestReplicate(t *testing.T) {
require.True(t, slices.Equal([]int{1, 1, 1, 1, 1}, Replicate(5, 1)))
}
func TestSpan(t *testing.T) {
x := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
lt5 := func(a int) bool { return a < 5 }
low, high := Span(lt5, x)
require.True(t, slices.Equal(low, []int{0, 1, 2, 3, 4}))
require.True(t, slices.Equal(high, []int{5, 6, 7, 8, 9}))
}
func TestSplitAt(t *testing.T) {
x := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
fst, snd := SplitAt(5, x)
require.True(t, slices.Equal(fst, []int{0, 1, 2, 3, 4}))
require.True(t, slices.Equal(snd, []int{5, 6, 7, 8, 9}))
}
func TestZipWith(t *testing.T) {
eq := func(a, b int) bool { return a == b }
x := []int{0, 1, 2, 3, 4}
y := Replicate(5, 1)
z := ZipWith(eq, x, y)
require.True(t, slices.Equal(
z, []bool{false, true, false, false, false},
))
}
// TestSum checks if the Sum function correctly calculates the sum of the
// numbers in the slice.
func TestSum(t *testing.T) {
tests := []struct {
name string
items interface{}
result interface{}
}{
{
name: "Sum of positive integers",
items: []int{1, 2, 3},
result: 6,
},
{
name: "Sum of negative integers",
items: []int{-1, -2, -3},
result: -6,
},
{
name: "Sum of float numbers",
items: []float64{1.1, 2.2, 3.3},
result: 6.6,
},
{
name: "Sum of complex numbers",
items: []complex128{
complex(1, 1),
complex(2, 2),
complex(3, 3),
},
result: complex(6, 6),
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
switch v := tt.items.(type) {
case []int:
require.Equal(t, tt.result, Sum(v))
case []float64:
require.Equal(t, tt.result, Sum(v))
case []complex128:
require.Equal(t, tt.result, Sum(v))
}
})
}
}
// TestSliceToMap tests the SliceToMap function.
func TestSliceToMap(t *testing.T) {
tests := []struct {
name string
slice []int
keyFunc func(int) int
valueFunc func(int) string
expected map[int]string
}{
{
name: "Integers to string map",
slice: []int{1, 2, 3},
keyFunc: func(a int) int { return a },
valueFunc: func(a int) string {
return fmt.Sprintf("Value%d", a)
},
expected: map[int]string{
1: "Value1",
2: "Value2",
3: "Value3",
},
},
{
name: "Duplicates in slice",
slice: []int{1, 2, 2, 3},
keyFunc: func(a int) int { return a },
valueFunc: func(a int) string {
return fmt.Sprintf("Value%d", a)
},
expected: map[int]string{
1: "Value1",
2: "Value2",
3: "Value3",
},
},
{
name: "Empty slice",
slice: []int{},
keyFunc: func(a int) int { return a },
valueFunc: func(a int) string {
return fmt.Sprintf("Value%d", a)
},
expected: map[int]string{},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
require.Equal(
t, tt.expected,
SliceToMap(tt.slice, tt.keyFunc, tt.valueFunc),
)
})
}
}
// TestHasDuplicates tests the HasDuplicates function.
func TestHasDuplicates(t *testing.T) {
// Define test cases.
testCases := []struct {
name string
items []int
want bool
}{
{
name: "All unique",
items: []int{1, 2, 3, 4, 5},
want: false,
},
{
name: "Some duplicates",
items: []int{1, 2, 2, 3, 4},
want: true,
},
{
name: "No items",
items: []int{},
want: false,
},
{
name: "All duplicates",
items: []int{1, 1, 1, 1},
want: true,
},
}
// Execute each test case.
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
got := HasDuplicates(tc.items)
require.Equal(t, tc.want, got)
})
}
}
// TestPropForEachConcMapIsomorphism ensures the property that ForEachConc and
// Map always yield the same results.
func TestPropForEachConcMapIsomorphism(t *testing.T) {
f := func(incSize int, s []int) bool {
inc := func(i int) int { return i + incSize }
mapped := Map(inc, s)
conc := ForEachConc(inc, s)
return slices.Equal(mapped, conc)
}
if err := quick.Check(f, nil); err != nil {
t.Fatal(err)
}
}
// TestPropForEachConcOutperformsMapWhenExpensive ensures the property that
// ForEachConc will beat Map in a race in circumstances where the computation in
// the argument closure is expensive.
func TestPropForEachConcOutperformsMapWhenExpensive(t *testing.T) {
f := func(incSize int, s []int) bool {
if len(s) < 2 {
// Intuitively we don't expect the extra overhead of
// ForEachConc to justify itself for list sizes of 1 or
// 0.
return true
}
inc := func(i int) int {
time.Sleep(time.Millisecond)
return i + incSize
}
c := make(chan bool, 1)
go func() {
Map(inc, s)
select {
case c <- false:
default:
}
}()
go func() {
ForEachConc(inc, s)
select {
case c <- true:
default:
}
}()
return <-c
}
if err := quick.Check(f, nil); err != nil {
t.Fatal(err)
}
}
func TestPropFindIdxFindIdentity(t *testing.T) {
f := func(div, mod uint8, s []uint8) bool {
if div == 0 || div == 1 {
return true
}
pred := func(i uint8) bool {
return i%div == mod
}
foundIdx := FindIdx(pred, s)
// onlyVal :: Option[T2[A, B]] -> Option[B]
onlyVal := MapOption(func(t2 T2[int, uint8]) uint8 {
return t2.Second()
})
valuesEqual := Find(pred, s) == onlyVal(foundIdx)
idxGetsVal := ElimOption(
foundIdx,
func() bool { return true },
func(t2 T2[int, uint8]) bool {
return s[t2.First()] == t2.Second()
})
return valuesEqual && idxGetsVal
}
if err := quick.Check(f, nil); err != nil {
t.Fatal(err)
}
}