refactor: add comparisons pkg for reused helpers

This commit moves the helper functions from
provider.go to a new comparisons package. This
package will be used by provider, tests, and
resources. The refactoring will assist with
splitting resources into resource specific
packages.

The previous helper functions have been deprecated
and will be removed in a future commit.

Signed-off-by: Marques Johansson <mjohansson@equinix.com>

equinix/provider.go

@@ -193,6 +193,10 @@ func configureProvider(ctx context.Context, d *schema.ResourceData, p *schema.Pr
 	return &config, nil
 }
 
+// stringsFound returns true if all strings in source are found in target
+// Deprecated: stringsFound is shared between provider, tests, and resources
+// and is being relocated for package refactoring.
+// Use github.com/equinix/terraform-provider-equinix/internal/comparisons.Subsets
 func stringsFound(source []string, target []string) bool {
 	for i := range source {
 		if !slices.Contains(target, source[i]) {
@@ -202,6 +206,10 @@ func stringsFound(source []string, target []string) bool {
 	return true
 }
 
+// isEmpty returns true if the value is nil or zero
+// Deprecated: isEmpty is shared between provider, tests, and resources
+// and is being relocated for package refactoring.
+// Use github.com/equinix/terraform-provider-equinix/internal/comparisons.IsEmpty
 func isEmpty(v interface{}) bool {
 	switch v := v.(type) {
 	case int:
@@ -219,6 +227,10 @@ func isEmpty(v interface{}) bool {
 	}
 }
 
+// slicesMatch returns true if all strings in s1 are found in s2
+// Deprecated: slicesMatch is shared between provider, tests, and resources
+// and is being relocated for package refactoring.
+// Use github.com/equinix/terraform-provider-equinix/internal/comparisons.SlicesMatch
 func slicesMatch(s1, s2 []string) bool {
 	if len(s1) != len(s2) {
 		return false

internal/comparisons/comparisons.go

@@ -0,0 +1,85 @@
+package comparisons
+
+import (
+	"cmp"
+	"slices"
+	"strings"
+)
+
+// IntValue returns the value of a given int pointer
+// or 0 if the pointer is nil
+func intValue(i *int) int {
+	if i != nil {
+		return *i
+	}
+	return 0
+}
+
+// StringValue returns the value of a given string pointer
+// or empty string if the pointer is nil
+func stringValue(s *string) string {
+	if s != nil {
+		return *s
+	}
+	return ""
+}
+
+// isEmpty returns true if the given value is empty
+func IsEmpty(v interface{}) bool {
+	switch v := v.(type) {
+	case int:
+		return v == 0
+	case *int:
+		return intValue(v) == 0
+	case string:
+		return v == ""
+	case *string:
+		return stringValue(v) == ""
+	case nil:
+		return true
+	default:
+		return false
+	}
+}
+
+// Subsets returns true if the first slice is a subset of the second slice
+func Subsets[T cmp.Ordered](s1, s2 []T) bool {
+	// Iterate over the first slice
+	for _, e := range s1 {
+		// If the element is not in the second slice, return false
+		if !slices.Contains(s2, e) {
+			return false
+		}
+	}
+
+	return true
+}
+
+// comparisons.SlicesMatch returns true if the two slices contain the same elements, regardless of order
+func SlicesMatch[T cmp.Ordered](s1, s2 []T) bool {
+	if len(s1) != len(s2) {
+		return false
+	}
+
+	// Create copies of the slices to avoid mutating the input slices
+	s1Copy := append([]T(nil), s1...)
+	s2Copy := append([]T(nil), s2...)
+
+	// Sort the slices
+	slices.Sort(s1Copy)
+	slices.Sort(s2Copy)
+
+	return slices.Equal(s1Copy, s2Copy)
+}
+
+// caseInsensitiveLess is a comparison function for sorting strings case-insensitively
+func caseInsensitiveLess(s1, s2 string) int {
+	switch {
+	case strings.ToLower(s1) == strings.ToLower(s2):
+		return 0
+	case strings.ToLower(s1) < strings.ToLower(s2):
+		return -1
+	default:
+		return 1
+	}
+}

internal/comparisons/comparisons_test.go

@@ -0,0 +1,89 @@
+package comparisons_test
+
+import (
+	"testing"
+
+	"github.com/equinix/terraform-provider-equinix/internal/comparisons"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSubsets(t *testing.T) {
+	// given
+	needles := []string{"key1", "key5"}
+	hay := []string{"key1", "key2", "Key3", "key4", "key5"}
+	// when
+	result := comparisons.Subsets(needles, hay)
+	// then
+	assert.True(t, result, "Given strings were found")
+}
+
+func TestSubsets_negative(t *testing.T) {
+	// given
+	needles := []string{"key1", "key6"}
+	hay := []string{"key1", "key2", "Key3", "key4", "key5"}
+	// when
+	result := comparisons.Subsets(hay, needles)
+	// then
+	assert.False(t, result, "Given strings were found")
+}
+
+func TestIsEmpty(t *testing.T) {
+	// given
+	input := []interface{}{
+		"test",
+		"",
+		nil,
+		123,
+		0,
+		43.43,
+	}
+	expected := []bool{
+		false,
+		true,
+		true,
+		false,
+		true,
+		false,
+		true,
+	}
+	// when then
+	for i := range input {
+		assert.Equal(t, expected[i], comparisons.IsEmpty(input[i]), "Input %v produces expected result %v", input[i], expected[i])
+	}
+}
+
+func TestSlicesMatch(t *testing.T) {
+	// given
+	input := [][][]string{
+		{
+			{"DC", "SV", "FR"},
+			{"FR", "SV", "DC"},
+		},
+		{
+			{"SV"},
+			{},
+		},
+		{
+			{"DC", "DC", "DC"},
+			{"DC", "SV", "DC"},
+		},
+		{
+			{}, {},
+		},
+	}
+	expected := []bool{
+		true,
+		false,
+		false,
+		true,
+	}
+	// when
+	results := make([]bool, len(expected))
+	for i := range input {
+		results[i] = comparisons.SlicesMatch(input[i][0], input[i][1])
+	}
+	// then
+	for i := range expected {
+		assert.Equal(t, expected[i], results[i])
+	}
+}