Add URL validation checker and tests to v2. (#140)

# Describe Request

Add URL validation checker and tests to v2.

# Change Type

New code.

v2/maker.go

@@ -32,6 +32,7 @@ var makers = map[string]MakeCheckFunc{
 	nameMinLen:       makeMinLen,
 	nameRequired:     makeRequired,
 	nameTrimSpace:    makeTrimSpace,
+	nameURL:          makeURL,
 }
 
 // makeChecks take a checker config and returns the check functions.

v2/url.go

@@ -0,0 +1,41 @@
+// Copyright (c) 2023-2024 Onur Cinar.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+// https://github.com/cinar/checker
+
+package v2
+
+import (
+	"net/url"
+	"reflect"
+)
+
+const (
+	// nameURL is the name of the URL check.
+	nameURL = "url"
+)
+
+var (
+	// ErrNotURL indicates that the given value is not a valid URL.
+	ErrNotURL = NewCheckError("URL")
+)
+
+// IsURL checks if the value is a valid URL.
+func IsURL(value string) (string, error) {
+	_, err := url.ParseRequestURI(value)
+	if err != nil {
+		return value, ErrNotURL
+	}
+	return value, nil
+}
+
+// checkURL checks if the value is a valid URL.
+func checkURL(value reflect.Value) (reflect.Value, error) {
+	_, err := IsURL(value.Interface().(string))
+	return value, err
+}
+
+// makeURL makes a checker function for the URL checker.
+func makeURL(_ string) CheckFunc[reflect.Value] {
+	return checkURL
+}

v2/url_test.go

@@ -0,0 +1,76 @@
+// Copyright (c) 2023-2024 Onur Cinar.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+// https://github.com/cinar/checker
+
+package v2_test
+
+import (
+	"fmt"
+	"testing"
+
+	v2 "github.com/cinar/checker/v2"
+)
+
+func ExampleIsURL() {
+	_, err := v2.IsURL("https://example.com")
+	if err != nil {
+		fmt.Println(err)
+	}
+}
+
+func TestIsURLInvalid(t *testing.T) {
+	_, err := v2.IsURL("invalid-url")
+	if err == nil {
+		t.Fatal("expected error")
+	}
+}
+
+func TestIsURLValid(t *testing.T) {
+	_, err := v2.IsURL("https://example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestCheckURLNonString(t *testing.T) {
+	defer FailIfNoPanic(t, "expected panic")
+
+	type Website struct {
+		Link int `checkers:"url"`
+	}
+
+	website := &Website{}
+
+	v2.CheckStruct(website)
+}
+
+func TestCheckURLInvalid(t *testing.T) {
+	type Website struct {
+		Link string `checkers:"url"`
+	}
+
+	website := &Website{
+		Link: "invalid-url",
+	}
+
+	_, ok := v2.CheckStruct(website)
+	if ok {
+		t.Fatal("expected error")
+	}
+}
+
+func TestCheckURLValid(t *testing.T) {
+	type Website struct {
+		Link string `checkers:"url"`
+	}
+
+	website := &Website{
+		Link: "https://example.com",
+	}
+
+	_, ok := v2.CheckStruct(website)
+	if !ok {
+		t.Fatal("expected valid")
+	}
+}