Merge pull request #37 from rezakhademix/add-in-validation-function

added: in validation generic function

in.go

@@ -0,0 +1,12 @@
+package validator
+
+// In checks value under validation must be included in the given list of values
+func In[T comparable](value T, acceptableValues ...T) bool {
+	for i := range acceptableValues {
+		if value == acceptableValues[i] {
+			return true
+		}
+	}
+
+	return false
+}

in_test.go

@@ -0,0 +1,65 @@
+package validator
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_In(t *testing.T) {
+	tests := []struct {
+		name             string
+		value            any
+		acceptableValues []any
+		expectedResult   bool
+	}{
+		{
+			name:             "test integer value does not exist in acceptableValues",
+			value:            4,
+			acceptableValues: []any{1, 2, 3},
+			expectedResult:   false,
+		},
+		{
+			name:             "test string value does not exist in acceptable values",
+			value:            "redis",
+			acceptableValues: []any{"mysql", "mariadb", "postgres"},
+			expectedResult:   false,
+		},
+		{
+			name:             "test empty string value does not exist in acceptable values",
+			value:            "",
+			acceptableValues: []any{"pen", "pencil", "pipe"},
+			expectedResult:   false,
+		},
+		{
+			name:             "test empty space string value does not exist in acceptable values",
+			value:            " ",
+			acceptableValues: []any{"joe", "jane", "john"},
+			expectedResult:   false,
+		},
+		{
+			name:             "test integer value exists in acceptable values",
+			value:            20,
+			acceptableValues: []any{10, 20, 30},
+			expectedResult:   true,
+		},
+		{
+			name:             "test string value exists in acceptable values",
+			value:            "go",
+			acceptableValues: []any{"go", "php", "java"},
+			expectedResult:   true,
+		},
+	}
+
+	for _, test := range tests {
+		result := In(test.value, test.acceptableValues...)
+
+		assert.Equalf(
+			t,
+			test.expectedResult,
+			result,
+			"test case %q failed: expected %v, got %v",
+			test.name, test.expectedResult, result,
+		)
+	}
+}