Merge pull request #50 from rezakhademix/add-max-min-string-len-valid…

…ation-rule

added: min, max string validation rule

max.go

@@ -1,10 +1,16 @@
 package validator
 
+import "strings"
+
 const (
 	// Max represents the rule name which will be used to find the default error message.
 	Max = "max"
+	// MaxString represents the rule name which will be used to find the default error message.
+	MaxString = "maxString"
 	// MaxMsg is the default error message format for fields with the maximum validation rule.
 	MaxMsg = "%s should be less than %v"
+	// MaxStringMsg is the default error message format for fields with the MaxString validation rule.
+	MaxStringMsg = "%s should has less than %v characters"
 )
 
 // MaxInt checks if the integer value is less than or equal the given max value.
@@ -28,3 +34,14 @@ func (v *Validator) MaxFloat(f, max float64, field, msg string) *Validator {
 
 	return v
 }
+
+// MaxString checks if the length of given string is less than or equal the given max value.
+//
+// Example:
+//
+//	validator.MaxString("rey", 5, "name", "name should has less than 5 characters.")
+func (v *Validator) MaxString(s string, maxLen int, field, msg string) *Validator {
+	v.Check(len(strings.TrimSpace(s)) <= maxLen, field, v.msg(MaxString, msg, field, maxLen))
+
+	return v
+}

max_test.go

@@ -123,3 +123,71 @@ func Test_MaxFloat64(t *testing.T) {
 		}
 	}
 }
+
+func Test_MaxString(t *testing.T) {
+	tests := []struct {
+		name        string
+		field       string
+		value       string
+		max         int
+		isPassed    bool
+		msg         string
+		expectedMsg string
+	}{
+		{
+			name:        "test `rey` will pass validation when maximum valid length is 5",
+			field:       "name",
+			value:       "rey",
+			max:         5,
+			isPassed:    true,
+			msg:         "",
+			expectedMsg: "",
+		},
+		{
+			name:        "test empty string will pass validation when maximum valid length is 2",
+			field:       "username",
+			value:       "",
+			max:         2,
+			isPassed:    true,
+			msg:         "",
+			expectedMsg: "",
+		},
+		{
+			name:        "test empty space string won't pass validation when maximum valid length is 0",
+			field:       "username",
+			value:       " ",
+			max:         -1,
+			isPassed:    false,
+			msg:         "",
+			expectedMsg: "username should has less than -1 characters",
+		},
+		{
+			name:        "test `abcd` won't pass validation when maximum valid length is 3",
+			field:       "alphabet",
+			value:       "abcd",
+			max:         3,
+			isPassed:    false,
+			msg:         "alphabet should has less than 3 characters",
+			expectedMsg: "alphabet should has less than 3 characters",
+		},
+	}
+
+	v := New()
+
+	for _, test := range tests {
+		v.MaxString(test.value, test.max, test.field, test.msg)
+
+		assert.Equal(t, test.isPassed, v.IsPassed())
+
+		if !test.isPassed {
+			assert.Equalf(
+				t,
+				test.expectedMsg,
+				v.Errors()[test.field],
+				"test case %q failed: expected: %s, got: %s",
+				test.expectedMsg,
+				v.Errors()[test.field],
+			)
+		}
+	}
+}

min.go

@@ -1,10 +1,16 @@
 package validator
 
+import "strings"
+
 const (
 	// Min represents the rule name which will be used to find the default error message.
 	Min = "min"
+	// MinString represents the rule name which will be used to find the default error message.
+	MinString = "minString"
 	// MinMsg is the default error message format for fields with the minimum validation rule.
 	MinMsg = "%s should be more than %v"
+	// MinStringMsg is the default error message format for fields with the MinString validation rule.
+	MinStringMsg = "%s should has more than %v characters"
 )
 
 // MinInt checks if the given integer value is greater than or equal the given min value.
@@ -28,3 +34,14 @@ func (v *Validator) MinFloat(f, min float64, field, msg string) *Validator {
 
 	return v
 }
+
+// MinString checks if the length of given string is greater than or equal the given min value.
+//
+// Example:
+//
+//	validator.MinString("rey", 5, "name", "name should has more than 5 characters.")
+func (v *Validator) MinString(s string, minLen int, field, msg string) *Validator {
+	v.Check(len(strings.TrimSpace(s)) >= minLen, field, v.msg(MinString, msg, field, minLen))
+
+	return v
+}

min_test.go

@@ -132,3 +132,71 @@ func Test_MinFloat(t *testing.T) {
 		}
 	}
 }
+
+func Test_MinString(t *testing.T) {
+	tests := []struct {
+		name        string
+		field       string
+		value       string
+		min         int
+		isPassed    bool
+		msg         string
+		expectedMsg string
+	}{
+		{
+			name:        "test `rey` will pass validation when minimum valid length is 2",
+			field:       "name",
+			value:       "rey",
+			min:         2,
+			isPassed:    true,
+			msg:         "",
+			expectedMsg: "",
+		},
+		{
+			name:        "test empty string won't pass validation when minimum valid length is 5",
+			field:       "username",
+			value:       "",
+			min:         5,
+			isPassed:    false,
+			msg:         "",
+			expectedMsg: "username should has more than 5 characters",
+		},
+		{
+			name:        "test empty space string won't pass validation when minimum valid length is 2",
+			field:       "username",
+			value:       " ",
+			min:         2,
+			isPassed:    false,
+			msg:         "",
+			expectedMsg: "username should has more than 2 characters",
+		},
+		{
+			name:        "test `abcd` won't pass validation when minimum valid length is 7",
+			field:       "alphabet",
+			value:       "abcd",
+			min:         7,
+			isPassed:    false,
+			msg:         "alphabet should has more than 7 characters",
+			expectedMsg: "alphabet should has more than 7 characters",
+		},
+	}
+
+	v := New()
+
+	for _, test := range tests {
+		v.MinString(test.value, test.min, test.field, test.msg)
+
+		assert.Equal(t, test.isPassed, v.IsPassed())
+
+		if !test.isPassed {
+			assert.Equalf(
+				t,
+				test.expectedMsg,
+				v.Errors()[test.field],
+				"test case %q failed: expected: %s, got: %s",
+				test.expectedMsg,
+				v.Errors()[test.field],
+			)
+		}
+	}
+}

validator.go

@@ -33,6 +33,8 @@ var (
 		Len:       LenMsg,
 		LenList:   LenListMsg,
 		Max:       MaxMsg,
+		MaxString: MaxStringMsg,
+		MinString: MinStringMsg,
 		Min:       MinMsg,
 		Between:   BetweenMsg,
 		NotExists: NotExistsMsg,
@@ -43,7 +45,7 @@ var (
 	}
 
 	// ErrMethodMessageNotFound is the default message when a method does not have any error message on methodToErrorMessage.
-	ErrMethodMessageNotFound = errors.New("method message does not exist")
+	ErrMethodMessageNotFound = errors.New("method default validation message does not exist in methodToErrorMessage")
 )
 
 // New will return a new validator

validator_test.go

@@ -17,19 +17,19 @@ func Test_msg(t *testing.T) {
 			name:        "test not exists method will result a panic",
 			method:      "qwert",
 			msg:         "",
-			expectedMsg: "method message does not exist",
+			expectedMsg: "method default validation message does not exist in methodToErrorMessage",
 		},
 		{
 			name:        "test empty string method will result a panic",
 			method:      "",
 			msg:         "",
-			expectedMsg: "method message does not exist",
+			expectedMsg: "method default validation message does not exist in methodToErrorMessage",
 		},
 		{
 			name:        "test empty space string method will result a panic",
 			method:      " ",
 			msg:         "",
-			expectedMsg: "method message does not exist",
+			expectedMsg: "method default validation message does not exist in methodToErrorMessage",
 		},
 	}