Min length checker added.

checker.go

@@ -31,8 +31,9 @@ const ResultValid Result = "VALID"
 
 // makers provides mapping to maker function for the checkers.
 var makers = map[string]MakeFunc{
-	"required": makeRequired,
-	"same":     makeSame,
+	CheckerMinLength: makeMinLength,
+	CheckerRequired:  makeRequired,
+	CheckerSame:      makeSame,
 }
 
 // Register registers the given checker name and the maker function.

minlenght.go

@@ -0,0 +1,39 @@
+package checker
+
+import (
+	"reflect"
+	"strconv"
+)
+
+// CheckerMinLength is the name of the checker.
+const CheckerMinLength = "min-length"
+
+// ResultNotMinLength indicates that the length of the given value is below the defined number.
+const ResultNotMinLength = "NOT_MIN_LENGTH"
+
+// IsMinLength checks if the length of the given value is greather than the given minimum length.
+func IsMinLength(value interface{}, minLength int) Result {
+	return checkMinLength(reflect.Indirect(reflect.ValueOf(value)), reflect.ValueOf(nil), minLength)
+}
+
+// makeMinLength makes a checker function for the min length checker.
+func makeMinLength(config string) CheckFunc {
+	minLength, err := strconv.Atoi(config)
+	if err != nil {
+		panic("unable to parse min length value")
+	}
+
+	return func(value, parent reflect.Value) Result {
+		return checkMinLength(value, parent, minLength)
+	}
+}
+
+// checkMinLength checks if the length of the given value is greather than the given minimum length.
+// The function uses the reflect.Value.Len() function to determine the length of the value.
+func checkMinLength(value, _ reflect.Value, minLength int) Result {
+	if value.Len() < minLength {
+		return ResultNotMinLength
+	}
+
+	return ResultValid
+}

minlength_test.go

@@ -0,0 +1,57 @@
+package checker
+
+import "testing"
+
+func TestIsMinLengthValid(t *testing.T) {
+	s := "1234"
+
+	if IsMinLength(s, 4) != ResultValid {
+		t.Fail()
+	}
+}
+
+func TestCheckMinLengthInvalidConfig(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Fail()
+		}
+	}()
+
+	type User struct {
+		Password string `checkers:"min-length:AB"`
+	}
+
+	user := &User{}
+
+	Check(user)
+}
+
+func TestCheckMinLengthValid(t *testing.T) {
+	type User struct {
+		Password string `checkers:"min-length:4"`
+	}
+
+	user := &User{
+		Password: "1234",
+	}
+
+	_, ok := Check(user)
+	if !ok {
+		t.Fail()
+	}
+}
+
+func TestCheckMinLengthInvalid(t *testing.T) {
+	type User struct {
+		Password string `checkers:"min-length:4"`
+	}
+
+	user := &User{
+		Password: "12",
+	}
+
+	_, ok := Check(user)
+	if ok {
+		t.Fail()
+	}
+}

required.go

@@ -2,6 +2,9 @@ package checker
 
 import "reflect"
 
+// CheckerRequired is the name of the checker.
+const CheckerRequired = "required"
+
 // ResultRequired indicates that the required value is missing.
 const ResultRequired Result = "REQUIRED"
 

same.go

@@ -4,6 +4,9 @@ import (
 	"reflect"
 )
 
+// CheckerSame is the name of the checker.
+const CheckerSame = "same"
+
 // ResultNotSame indicates that the given two values are not equal to each other.
 const ResultNotSame = "NOT_SAME"