Add validator lib

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

pkg/validator/double_pointer_test.go

@@ -0,0 +1,98 @@
+// Copyright (c) 2025 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package validator_test
+
+import (
+	"testing"
+
+	"go.probo.inc/probo/pkg/validator"
+)
+
+func TestDoublePointerValidation(t *testing.T) {
+	t.Run("valid double pointer string", func(t *testing.T) {
+		v := validator.New()
+		str := "hello"
+		ptr := &str
+		doublePtr := &ptr
+
+		v.Check(doublePtr, "name", validator.Required(), validator.NotEmpty(), validator.MaxLen(1000))
+
+		if v.HasErrors() {
+			t.Errorf("expected no errors, got: %v", v.Error())
+		}
+	})
+
+	t.Run("invalid double pointer string - empty", func(t *testing.T) {
+		v := validator.New()
+		str := ""
+		ptr := &str
+		doublePtr := &ptr
+
+		v.Check(doublePtr, "name", validator.Required(), validator.NotEmpty())
+
+		if !v.HasErrors() {
+			t.Error("expected errors for empty string")
+		}
+	})
+
+	t.Run("invalid double pointer string - too long", func(t *testing.T) {
+		v := validator.New()
+		str := "this is a very long string that exceeds the maximum length"
+		ptr := &str
+		doublePtr := &ptr
+
+		v.Check(doublePtr, "name", validator.Required(), validator.MaxLen(10))
+
+		if !v.HasErrors() {
+			t.Error("expected errors for string exceeding max length")
+		}
+	})
+
+	t.Run("optional double pointer - nil outer pointer", func(t *testing.T) {
+		v := validator.New()
+		var doublePtr **string = nil
+
+		v.Check(doublePtr, "name", validator.NotEmpty(), validator.MaxLen(1000))
+
+		if v.HasErrors() {
+			t.Errorf("expected no errors for nil optional field, got: %v", v.Error())
+		}
+	})
+
+	t.Run("optional double pointer - nil inner pointer", func(t *testing.T) {
+		v := validator.New()
+		var ptr *string = nil
+		doublePtr := &ptr
+
+		v.Check(doublePtr, "name", validator.NotEmpty(), validator.MaxLen(1000))
+
+		if v.HasErrors() {
+			t.Errorf("expected no errors for nil optional field, got: %v", v.Error())
+		}
+	})
+
+	t.Run("optional double pointer - valid value", func(t *testing.T) {
+		v := validator.New()
+		str := "hello"
+		ptr := &str
+		doublePtr := &ptr
+
+		v.Check(doublePtr, "name", validator.NotEmpty(), validator.MaxLen(1000))
+
+		if v.HasErrors() {
+			t.Errorf("expected no errors, got: %v", v.Error())
+		}
+	})
+}