Andrey Nering created
This should probably be moved into `x`.internal/slicesext/slices.go | 17 +++
internal/slicesext/slices_test.go | 158 +++++++++++++++++++++++++++++++++
2 files changed, 175 insertions(+)
@@ -0,0 +1,17 @@
+package slicesext
+
+func IsSubset[T comparable](a, b []T) bool {
+ if len(a) > len(b) {
+ return false
+ }
+ set := make(map[T]struct{}, len(b))
+ for _, item := range b {
+ set[item] = struct{}{}
+ }
+ for _, item := range a {
+ if _, exists := set[item]; !exists {
+ return false
+ }
+ }
+ return true
+}
@@ -0,0 +1,158 @@
+package slicesext
+
+import (
+ "testing"
+
+ "github.com/stretchr/testify/require"
+)
+
+func TestIsSubset(t *testing.T) {
+ tests := []struct {
+ name string
+ a []string
+ b []string
+ expect bool
+ }{
+ // Basic subset cases
+ {
+ name: "empty subset of empty",
+ a: []string{},
+ b: []string{},
+ expect: true,
+ },
+ {
+ name: "empty subset of non-empty",
+ a: []string{},
+ b: []string{"a", "b", "c"},
+ expect: true,
+ },
+ {
+ name: "non-empty not subset of empty",
+ a: []string{"a"},
+ b: []string{},
+ expect: false,
+ },
+ {
+ name: "single element subset",
+ a: []string{"b"},
+ b: []string{"a", "b", "c"},
+ expect: true,
+ },
+ {
+ name: "single element not subset",
+ a: []string{"d"},
+ b: []string{"a", "b", "c"},
+ expect: false,
+ },
+ {
+ name: "multiple elements subset",
+ a: []string{"a", "c"},
+ b: []string{"a", "b", "c", "d"},
+ expect: true,
+ },
+ {
+ name: "multiple elements not subset",
+ a: []string{"a", "e"},
+ b: []string{"a", "b", "c", "d"},
+ expect: false,
+ },
+ {
+ name: "equal sets are subsets",
+ a: []string{"a", "b", "c"},
+ b: []string{"a", "b", "c"},
+ expect: true,
+ },
+ {
+ name: "larger set not subset of smaller",
+ a: []string{"a", "b", "c", "d"},
+ b: []string{"a", "b"},
+ expect: false,
+ },
+
+ // Order independence
+ {
+ name: "subset with different order",
+ a: []string{"c", "a"},
+ b: []string{"b", "a", "d", "c"},
+ expect: true,
+ },
+
+ // Duplicate handling
+ {
+ name: "duplicates in subset",
+ a: []string{"a", "a", "b"},
+ b: []string{"a", "b", "c"},
+ expect: true,
+ },
+ {
+ name: "duplicates in superset",
+ a: []string{"a", "b"},
+ b: []string{"a", "a", "b", "b", "c"},
+ expect: true,
+ },
+ {
+ name: "duplicates in both",
+ a: []string{"a", "a", "b"},
+ b: []string{"a", "a", "b", "b", "c"},
+ expect: true,
+ },
+
+ // Real-world examples
+ {
+ name: "npm flags subset",
+ a: []string{"-g"},
+ b: []string{"-g", "--verbose", "--save-dev"},
+ expect: true,
+ },
+ {
+ name: "npm flags not subset",
+ a: []string{"--global"},
+ b: []string{"-g", "--verbose", "--save-dev"},
+ expect: false,
+ },
+ }
+
+ for _, tt := range tests {
+ t.Run(tt.name, func(t *testing.T) {
+ result := IsSubset(tt.a, tt.b)
+ require.Equal(t, tt.expect, result,
+ "IsSubset(%v, %v) should be %v", tt.a, tt.b, tt.expect)
+ })
+ }
+}
+
+func TestIsSubsetWithInts(t *testing.T) {
+ tests := []struct {
+ name string
+ a []int
+ b []int
+ expect bool
+ }{
+ {
+ name: "int subset",
+ a: []int{1, 3},
+ b: []int{1, 2, 3, 4},
+ expect: true,
+ },
+ {
+ name: "int not subset",
+ a: []int{1, 5},
+ b: []int{1, 2, 3, 4},
+ expect: false,
+ },
+ {
+ name: "empty int subset",
+ a: []int{},
+ b: []int{1, 2, 3},
+ expect: true,
+ },
+ }
+
+ for _, tt := range tests {
+ t.Run(tt.name, func(t *testing.T) {
+ result := IsSubset(tt.a, tt.b)
+ require.Equal(t, tt.expect, result,
+ "IsSubset(%v, %v) should be %v", tt.a, tt.b, tt.expect)
+ })
+ }
+}