lo/intersect_test.go

package lo

import (
	"errors"
	"strconv"
	"testing"

	"github.com/stretchr/testify/assert"
)

func TestContains(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := Contains([]int{0, 1, 2, 3, 4, 5}, 5)
	result2 := Contains([]int{0, 1, 2, 3, 4, 5}, 6)

	is.True(result1)
	is.False(result2)
}

func TestContainsBy(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	type a struct {
		A int
		B string
	}

	a1 := []a{{A: 1, B: "1"}, {A: 2, B: "2"}, {A: 3, B: "3"}}
	result1 := ContainsBy(a1, func(t a) bool { return t.A == 1 && t.B == "2" })
	result2 := ContainsBy(a1, func(t a) bool { return t.A == 2 && t.B == "2" })

	a2 := []string{"aaa", "bbb", "ccc"}
	result3 := ContainsBy(a2, func(t string) bool { return t == "ccc" })
	result4 := ContainsBy(a2, func(t string) bool { return t == "ddd" })

	is.False(result1)
	is.True(result2)
	is.True(result3)
	is.False(result4)
}

func TestEvery(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := Every([]int{0, 1, 2, 3, 4, 5}, []int{0, 2})
	result2 := Every([]int{0, 1, 2, 3, 4, 5}, []int{0, 6})
	result3 := Every([]int{0, 1, 2, 3, 4, 5}, []int{-1, 6})
	result4 := Every([]int{0, 1, 2, 3, 4, 5}, []int{})

	is.True(result1)
	is.False(result2)
	is.False(result3)
	is.True(result4)
}

func TestEveryBy(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := EveryBy([]int{1, 2, 3, 4}, func(x int) bool {
		return x < 5
	})

	is.True(result1)

	result2 := EveryBy([]int{1, 2, 3, 4}, func(x int) bool {
		return x < 3
	})

	is.False(result2)

	result3 := EveryBy([]int{1, 2, 3, 4}, func(x int) bool {
		return x < 0
	})

	is.False(result3)

	result4 := EveryBy([]int{}, func(x int) bool {
		return x < 5
	})

	is.True(result4)
}

func TestSome(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := Some([]int{0, 1, 2, 3, 4, 5}, []int{0, 2})
	result2 := Some([]int{0, 1, 2, 3, 4, 5}, []int{0, 6})
	result3 := Some([]int{0, 1, 2, 3, 4, 5}, []int{-1, 6})
	result4 := Some([]int{0, 1, 2, 3, 4, 5}, []int{})

	is.True(result1)
	is.True(result2)
	is.False(result3)
	is.False(result4)
}

func TestSomeBy(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := SomeBy([]int{1, 2, 3, 4}, func(x int) bool {
		return x < 5
	})

	is.True(result1)

	result2 := SomeBy([]int{1, 2, 3, 4}, func(x int) bool {
		return x < 3
	})

	is.True(result2)

	result3 := SomeBy([]int{1, 2, 3, 4}, func(x int) bool {
		return x < 0
	})

	is.False(result3)

	result4 := SomeBy([]int{}, func(x int) bool {
		return x < 5
	})

	is.False(result4)
}

func TestNone(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := None([]int{0, 1, 2, 3, 4, 5}, []int{0, 2})
	result2 := None([]int{0, 1, 2, 3, 4, 5}, []int{0, 6})
	result3 := None([]int{0, 1, 2, 3, 4, 5}, []int{-1, 6})
	result4 := None([]int{0, 1, 2, 3, 4, 5}, []int{})

	is.False(result1)
	is.False(result2)
	is.True(result3)
	is.True(result4)
}

func TestNoneBy(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := NoneBy([]int{1, 2, 3, 4}, func(x int) bool {
		return x < 5
	})

	is.False(result1)

	result2 := NoneBy([]int{1, 2, 3, 4}, func(x int) bool {
		return x < 3
	})

	is.False(result2)

	result3 := NoneBy([]int{1, 2, 3, 4}, func(x int) bool {
		return x < 0
	})

	is.True(result3)

	result4 := NoneBy([]int{}, func(x int) bool {
		return x < 5
	})

	is.True(result4)
}

func TestIntersect(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result0 := Intersect[int, []int]()
	result1 := Intersect([]int{1})
	result2 := Intersect([]int{0, 1, 2, 3, 4, 5}, []int{0, 2})
	result3 := Intersect([]int{0, 1, 2, 3, 4, 5}, []int{0, 6})
	result4 := Intersect([]int{0, 1, 2, 3, 4, 5}, []int{-1, 6})
	result5 := Intersect([]int{0, 6}, []int{0, 1, 2, 3, 4, 5})
	result6 := Intersect([]int{0, 6, 0}, []int{0, 1, 2, 3, 4, 5})
	result7 := Intersect([]int{0, 6, 0, 3}, []int{0, 1, 2, 3, 4, 5}, []int{0, 6})
	result8 := Intersect([]int{0, 6, 0, 3}, []int{0, 1, 2, 3, 4, 5}, []int{1, 6})
	result9 := Intersect([]int{0, 1, 1}, []int{2}, []int{3})
	resultA := Intersect([]int{0, 1, 1})

	is.Empty(result0)
	is.ElementsMatch([]int{1}, result1)
	is.ElementsMatch([]int{0, 2}, result2)
	is.ElementsMatch([]int{0}, result3)
	is.Empty(result4)
	is.ElementsMatch([]int{0}, result5)
	is.ElementsMatch([]int{0}, result6)
	is.ElementsMatch([]int{0}, result7)
	is.Empty(result8)
	is.Empty(result9)
	is.ElementsMatch([]int{0, 1}, resultA)

	type myStrings []string
	allStrings := myStrings{"", "foo", "bar"}
	nonempty := Intersect(allStrings, allStrings)
	is.IsType(nonempty, allStrings, "type preserved")
}

func TestIntersectBy(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	type User struct {
		ID   int
		Name string
	}

	list1 := []User{
		{ID: 1, Name: "Alice"},
		{ID: 2, Name: "Bob"},
		{ID: 3, Name: "Charlie"},
	}

	list2 := []User{
		{ID: 2, Name: "Robert"},
		{ID: 3, Name: "Charlie"},
		{ID: 4, Name: "Alice"},
	}

	intersectByID := IntersectBy(func(u User) int {
		return u.ID
	}, list1, list2)
	is.ElementsMatch(intersectByID, []User{{ID: 2, Name: "Bob"}, {ID: 3, Name: "Charlie"}})

	intersectByName := IntersectBy(func(u User) string {
		return u.Name
	}, list1, list2)
	is.ElementsMatch(intersectByName, []User{{ID: 3, Name: "Charlie"}, {ID: 1, Name: "Alice"}})

	intersectByIDAndName := IntersectBy(func(u User) string {
		return strconv.Itoa(u.ID) + u.Name
	}, list1, list2)
	is.ElementsMatch(intersectByIDAndName, []User{{ID: 3, Name: "Charlie"}})

	result := IntersectBy(strconv.Itoa, []int{0, 6, 0, 3}, []int{0, 1, 2, 3, 4, 5}, []int{0, 6})
	is.ElementsMatch(result, []int{0})

	result = IntersectBy(strconv.Itoa, []int{0, 1, 1})
	is.ElementsMatch(result, []int{0, 1})
}

func TestDifference(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	left1, right1 := Difference([]int{0, 1, 2, 3, 4, 5}, []int{0, 2, 6})
	is.Equal([]int{1, 3, 4, 5}, left1)
	is.Equal([]int{6}, right1)

	left2, right2 := Difference([]int{1, 2, 3, 4, 5}, []int{0, 6})
	is.Equal([]int{1, 2, 3, 4, 5}, left2)
	is.Equal([]int{0, 6}, right2)

	left3, right3 := Difference([]int{0, 1, 2, 3, 4, 5}, []int{0, 1, 2, 3, 4, 5})
	is.Empty(left3)
	is.Empty(right3)

	type myStrings []string
	allStrings := myStrings{"", "foo", "bar"}
	a, b := Difference(allStrings, allStrings)
	is.IsType(a, allStrings, "type preserved")
	is.IsType(b, allStrings, "type preserved")
}

func TestUnion(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := Union([]int{0, 1, 2, 3, 4, 5}, []int{0, 2, 10})
	result2 := Union([]int{0, 1, 2, 3, 4, 5}, []int{6, 7})
	result3 := Union([]int{0, 1, 2, 3, 4, 5}, []int{})
	result4 := Union([]int{0, 1, 2}, []int{0, 1, 2, 3, 3})
	result5 := Union([]int{0, 1, 2}, []int{0, 1, 2})
	result6 := Union([]int{}, []int{})
	is.Equal([]int{0, 1, 2, 3, 4, 5, 10}, result1)
	is.Equal([]int{0, 1, 2, 3, 4, 5, 6, 7}, result2)
	is.Equal([]int{0, 1, 2, 3, 4, 5}, result3)
	is.Equal([]int{0, 1, 2, 3}, result4)
	is.Equal([]int{0, 1, 2}, result5)
	is.Empty(result6)

	result11 := Union([]int{0, 1, 2, 3, 4, 5}, []int{0, 2, 10}, []int{0, 1, 11})
	result12 := Union([]int{0, 1, 2, 3, 4, 5}, []int{6, 7}, []int{8, 9})
	result13 := Union([]int{0, 1, 2, 3, 4, 5}, []int{}, []int{})
	result14 := Union([]int{0, 1, 2}, []int{0, 1, 2}, []int{0, 1, 2})
	result15 := Union([]int{}, []int{}, []int{})
	is.Equal([]int{0, 1, 2, 3, 4, 5, 10, 11}, result11)
	is.Equal([]int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, result12)
	is.Equal([]int{0, 1, 2, 3, 4, 5}, result13)
	is.Equal([]int{0, 1, 2}, result14)
	is.Empty(result15)

	type myStrings []string
	allStrings := myStrings{"", "foo", "bar"}
	nonempty := Union(allStrings, allStrings)
	is.IsType(nonempty, allStrings, "type preserved")
}

func TestWithout(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := Without([]int{0, 2, 10}, 0, 1, 2, 3, 4, 5)
	result2 := Without([]int{0, 7}, 0, 1, 2, 3, 4, 5)
	result3 := Without([]int{}, 0, 1, 2, 3, 4, 5)
	result4 := Without([]int{0, 1, 2}, 0, 1, 2)
	result5 := Without([]int{})
	is.Equal([]int{10}, result1)
	is.Equal([]int{7}, result2)
	is.Empty(result3)
	is.Empty(result4)
	is.Empty(result5)

	type myStrings []string
	allStrings := myStrings{"", "foo", "bar"}
	nonempty := Without(allStrings, "")
	is.IsType(nonempty, allStrings, "type preserved")
}

func TestWithoutBy(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	type User struct {
		Name string
		Age  int
	}

	result1 := WithoutBy([]User{{Name: "nick"}, {Name: "peter"}},
		func(item User) string {
			return item.Name
		}, "nick", "lily")
	result2 := WithoutBy([]User{}, func(item User) int { return item.Age }, 1, 2, 3)
	result3 := WithoutBy([]User{}, func(item User) string { return item.Name })
	is.Equal([]User{{Name: "peter"}}, result1)
	is.Empty(result2)
	is.Empty(result3)

	type myStrings []string
	allStrings := myStrings{"", "foo", "bar"}
	nonempty := WithoutBy(allStrings, func(s string) string {
		return s
	})
	is.IsType(nonempty, allStrings, "type preserved")
}

func TestWithoutByErr(t *testing.T) {
	t.Parallel()

	type User struct {
		Name string
		Age  int
	}

	tests := []struct {
		name          string
		input         []User
		iteratee      func(User) (string, error)
		exclude       []string
		want          []User
		wantErr       string
		wantCallCount int
	}{
		{
			name:  "exclude by name",
			input: []User{{Name: "nick"}, {Name: "peter"}},
			iteratee: func(item User) (string, error) {
				return item.Name, nil
			},
			exclude:       []string{"nick", "lily"},
			want:          []User{{Name: "peter"}},
			wantErr:       "",
			wantCallCount: 2,
		},
		{
			name:  "empty exclude list",
			input: []User{{Name: "nick"}, {Name: "peter"}},
			iteratee: func(item User) (string, error) {
				return item.Name, nil
			},
			exclude:       []string{},
			want:          []User{{Name: "nick"}, {Name: "peter"}},
			wantErr:       "",
			wantCallCount: 2,
		},
		{
			name:  "error on second element",
			input: []User{{Name: "nick"}, {Name: "peter"}, {Name: "lily"}},
			iteratee: func(item User) (string, error) {
				if item.Name == "peter" {
					return "", errors.New("peter not allowed")
				}
				return item.Name, nil
			},
			exclude:       []string{"nick"},
			want:          nil,
			wantErr:       "peter not allowed",
			wantCallCount: 2, // stops early at error
		},
		{
			name:  "error on first element",
			input: []User{{Name: "nick"}, {Name: "peter"}},
			iteratee: func(item User) (string, error) {
				return "", errors.New("first element error")
			},
			exclude:       []string{"nick"},
			want:          nil,
			wantErr:       "first element error",
			wantCallCount: 1,
		},
		{
			name:  "all excluded",
			input: []User{{Name: "nick"}, {Name: "peter"}},
			iteratee: func(item User) (string, error) {
				return item.Name, nil
			},
			exclude:       []string{"nick", "peter", "lily"},
			want:          []User{},
			wantErr:       "",
			wantCallCount: 2,
		},
		{
			name:  "none excluded",
			input: []User{{Name: "nick"}, {Name: "peter"}},
			iteratee: func(item User) (string, error) {
				return item.Name, nil
			},
			exclude:       []string{"alice"},
			want:          []User{{Name: "nick"}, {Name: "peter"}},
			wantErr:       "",
			wantCallCount: 2,
		},
	}

	for _, tt := range tests {
		tt := tt // capture range variable
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()
			is := assert.New(t)

			callCount := 0
			wrappedIteratee := func(item User) (string, error) {
				callCount++
				return tt.iteratee(item)
			}

			got, err := WithoutByErr(tt.input, wrappedIteratee, tt.exclude...)

			if tt.wantErr != "" {
				is.Error(err)
				is.Equal(tt.wantErr, err.Error())
				is.Nil(got)
				if tt.wantCallCount > 0 {
					is.Equal(tt.wantCallCount, callCount, "should stop early on error")
				}
			} else {
				is.NoError(err)
				is.Equal(tt.want, got)
				is.Equal(tt.wantCallCount, callCount)
			}
		})
	}

	t.Run("type preserved", func(t *testing.T) {
		t.Parallel()
		is := assert.New(t)

		type myStrings []string
		allStrings := myStrings{"", "foo", "bar"}
		nonempty, err := WithoutByErr(allStrings, func(s string) (string, error) {
			return s, nil
		})

		is.NoError(err)
		is.IsType(nonempty, allStrings, "type preserved")
	})
}

func TestWithoutEmpty(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := WithoutEmpty([]int{0, 1, 2})
	result2 := WithoutEmpty([]int{1, 2})
	result3 := WithoutEmpty([]int{})
	result4 := WithoutEmpty([]*int{ToPtr(0), ToPtr(1), nil, ToPtr(2)})
	is.Equal([]int{1, 2}, result1)
	is.Equal([]int{1, 2}, result2)
	is.Empty(result3)
	is.Equal([]*int{ToPtr(0), ToPtr(1), ToPtr(2)}, result4)

	type myStrings []string
	allStrings := myStrings{"", "foo", "bar"}
	nonempty := WithoutEmpty(allStrings)
	is.IsType(nonempty, allStrings, "type preserved")
}

func TestWithoutNth(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	result1 := WithoutNth([]int{5, 6, 7}, 1, 0)
	is.Equal([]int{7}, result1)

	result2 := WithoutNth([]int{1, 2})
	is.Equal([]int{1, 2}, result2)

	result3 := WithoutNth([]int{})
	is.Empty(result3)

	result4 := WithoutNth([]int{0, 1, 2, 3}, -1, 4)
	is.Equal([]int{0, 1, 2, 3}, result4)

	type myStrings []string
	allStrings := myStrings{"", "foo", "bar"}
	nonempty := WithoutNth(allStrings)
	is.IsType(nonempty, allStrings, "type preserved")

	// This works for non-comparable as well
	result5 := WithoutNth([]func() int{func() int { return 1 }, func() int { return 2 }, func() int { return 3 }}, 1)
	is.Equal([]int{1, 3}, Map(result5, func(f func() int, _ int) int { return f() }))
}

func TestElementsMatch(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	is.False(ElementsMatch([]int{}, []int{1}))
	is.False(ElementsMatch([]int{1}, []int{2}))
	is.False(ElementsMatch([]int{1}, []int{1, 2}))
	is.False(ElementsMatch([]int{1, 1, 2}, []int{2, 2, 1}))

	is.True(ElementsMatch([]int{}, nil))
	is.True(ElementsMatch([]int{1}, []int{1}))
	is.True(ElementsMatch([]int{1, 1}, []int{1, 1}))
	is.True(ElementsMatch([]int{1, 2}, []int{2, 1}))
	is.True(ElementsMatch([]int{1, 1, 2}, []int{1, 2, 1}))
}

func TestElementsMatchBy(t *testing.T) {
	t.Parallel()
	is := assert.New(t)

	type someType struct {
		key string
	}

	is.True(ElementsMatchBy(
		[]someType{{key: "a"}, {key: "b"}},
		[]someType{{key: "b"}, {key: "a"}},
		func(item someType) string { return item.key },
	))
}