diff --git a/helper.go b/helper.go
index 991b255..53311ae 100644
--- a/helper.go
+++ b/helper.go
@@ -13,10 +13,7 @@ func caseHelper(input string, isCamel bool, rule ...string) []string {
 		input = re.ReplaceAllString(input, ReplaceCapital)
 	}
 	input = strings.Join(strings.Fields(strings.TrimSpace(input)), " ")
-	if len(rule) <= 1 {
-		rule = []string{".", " ", "_", " ", "-", " "}
-	}
-	if len(rule) > 1 && len(rule)%2 != 0 {
+	if len(rule) > 0 && len(rule)%2 != 0 {
 		panic(errors.New(OddError))
 	}
 	rule = append(rule, ".", " ", "_", " ", "-", " ")
diff --git a/stringy.go b/stringy.go
index 313c48e..da70928 100644
--- a/stringy.go
+++ b/stringy.go
@@ -53,7 +53,7 @@ func New(val string) StringManipulation {
 // chain to upper which with make result all upercase or ToLower which
 // will make result all lower case or Get which will return result as it is
 func (i *input) Between(start, end string) StringManipulation {
-	if start == "" && end == "" || i.Input == "" {
+	if (start == "" && end == "") || i.Input == "" {
 		return i
 	}
 
@@ -179,7 +179,7 @@ func (i *input) Last(length int) string {
 func (i *input) LcFirst() string {
 	input := getInput(*i)
 	for i, v := range input {
-		return string(unicode.ToUpper(v)) + input[i+1:]
+		return string(unicode.ToLower(v)) + input[i+1:]
 	}
 	return input
 }
diff --git a/stringy_test.go b/stringy_test.go
index 62d5ac3..11a5d09 100644
--- a/stringy_test.go
+++ b/stringy_test.go
@@ -13,6 +13,22 @@ func TestInput_Between(t *testing.T) {
 	}
 }
 
+func TestInput_EmptyBetween(t *testing.T) {
+	sm := New("This is example.")
+	val := sm.Between("", "").ToUpper()
+	if val != "THIS IS EXAMPLE." {
+		t.Errorf("Expected: %s but got: %s", "THIS IS EXAMPLE.", val)
+	}
+}
+
+func TestInput_EmptyNoMatchBetween(t *testing.T) {
+	sm := New("This is example.")
+	val := sm.Between("hello", "test").ToUpper()
+	if val != "THIS IS EXAMPLE." {
+		t.Errorf("Expected: %s but got: %s", "THIS IS EXAMPLE.", val)
+	}
+}
+
 func TestInput_Boolean(t *testing.T) {
 	str := New("on")
 	val := str.Boolean()
@@ -21,6 +37,27 @@ func TestInput_Boolean(t *testing.T) {
 	}
 }
 
+func TestInput_BooleanOff(t *testing.T) {
+	str := New("off")
+	val := str.Boolean()
+	if val {
+		t.Errorf("Expected: to be false but got: %v", val)
+	}
+}
+
+func TestInput_BooleanError(t *testing.T) {
+	defer func() {
+		if err := recover(); err == nil {
+			t.Errorf("Error expected")
+		}
+	}()
+	str := New("invalid")
+	val := str.Boolean()
+	if val {
+		t.Errorf("Expected: to be false but got: %v", val)
+	}
+}
+
 func TestInput_CamelCase(t *testing.T) {
 	str := New("Camel case this_complicated__string%%")
 	val := str.CamelCase("%", "")
@@ -29,6 +66,28 @@ func TestInput_CamelCase(t *testing.T) {
 	}
 }
 
+func TestInput_CamelCaseNoRule(t *testing.T) {
+	str := New("Camel case this_complicated__string%%")
+	val := str.CamelCase()
+	if val != "CamelCaseThisComplicatedString%%" {
+		t.Errorf("Expected: to be %s but got: %s", "CamelCaseThisComplicatedString", val)
+	}
+}
+
+func TestInput_CamelCaseOddRuleError(t *testing.T) {
+	defer func() {
+		if err := recover(); err == nil {
+			t.Errorf("Error expected")
+		}
+	}()
+	str := New("Camel case this_complicated__string%%")
+	val := str.CamelCase("%")
+
+	if val != "CamelCaseThisComplicatedString%%" {
+		t.Errorf("Expected: to be %s but got: %s", "CamelCaseThisComplicatedString", val)
+	}
+}
+
 func TestInput_ContainsAll(t *testing.T) {
 	contains := New("hello mam how are you??")
 	if val := contains.ContainsAll("mam", "?"); !val {
@@ -47,6 +106,14 @@ func TestInput_Delimited(t *testing.T) {
 	}
 }
 
+func TestInput_DelimitedNoDelimeter(t *testing.T) {
+	str := New("Delimited case this_complicated__string@@")
+	against := "delimited.case.this.complicated.string@@"
+	if val := str.Delimited("").ToLower(); val != against {
+		t.Errorf("Expected: to be %s but got: %s", against, val)
+	}
+}
+
 func TestInput_KebabCase(t *testing.T) {
 	str := New("Kebab case this-complicated___string@@")
 	against := "Kebab-case-this-complicated-string"
@@ -56,8 +123,16 @@ func TestInput_KebabCase(t *testing.T) {
 }
 
 func TestInput_LcFirst(t *testing.T) {
-	str := New("this is an all lower")
-	against := "This is an all lower"
+	str := New("This is an all lower")
+	against := "this is an all lower"
+	if val := str.LcFirst(); val != against {
+		t.Errorf("Expected: to be %s but got: %s", against, val)
+	}
+}
+
+func TestInput_LcFirstEmpty(t *testing.T) {
+	str := New("")
+	against := ""
 	if val := str.LcFirst(); val != against {
 		t.Errorf("Expected: to be %s but got: %s", against, val)
 	}
@@ -87,6 +162,23 @@ func TestInput_Pad(t *testing.T) {
 	}
 }
 
+func TestInput_PadInvalidLength(t *testing.T) {
+	pad := New("Roshan")
+	if result := pad.Pad(6, "0", "both"); result != "Roshan" {
+		t.Errorf("Expected: %s but got: %s", "Roshan", result)
+	}
+	if result := pad.Pad(6, "0", "left"); result != "Roshan" {
+		t.Errorf("Expected: %s but got: %s", "Roshan", result)
+	}
+	if result := pad.Pad(6, "0", "right"); result != "Roshan" {
+		t.Errorf("Expected: %s but got: %s", "Roshan", result)
+	}
+
+	if result := pad.Pad(13, "0", "middle"); result != "Roshan" {
+		t.Errorf("Expected: %s but got: %s", "Roshan", result)
+	}
+}
+
 func TestInput_RemoveSpecialCharacter(t *testing.T) {
 	cleanString := New("special@#remove%%%%")
 	against := "specialremove"
@@ -103,6 +195,14 @@ func TestInput_ReplaceFirst(t *testing.T) {
 	}
 }
 
+func TestInput_ReplaceFirstEmptyInput(t *testing.T) {
+	replaceFirst := New("")
+	against := ""
+	if result := replaceFirst.ReplaceFirst("name", "nombre"); result != against {
+		t.Errorf("Expected: %s but got: %s", against, result)
+	}
+}
+
 func TestInput_ReplaceLast(t *testing.T) {
 	replaceLast := New("Hello My name is Roshan and his name is Alis.")
 	against := "Hello My name is Roshan and his nombre is Alis."
@@ -151,6 +251,14 @@ func TestInput_Tease(t *testing.T) {
 	}
 }
 
+func TestInput_TeaseEmpty(t *testing.T) {
+	str := New("This is just simple paragraph on lorem ipsum.")
+	against := "This is just simple paragraph on lorem ipsum."
+	if val := str.Tease(200, "..."); val != against {
+		t.Errorf("Expected: to be %s but got: %s", against, val)
+	}
+}
+
 func TestInput_UcFirst(t *testing.T) {
 	str := New("this is test")
 	against := "This is test"
@@ -159,6 +267,14 @@ func TestInput_UcFirst(t *testing.T) {
 	}
 }
 
+func TestInput_EmptyUcFirst(t *testing.T) {
+	str := New("")
+	against := ""
+	if val := str.UcFirst(); val != against {
+		t.Errorf("Expected: to be %s but got: %s", against, val)
+	}
+}
+
 func TestInput_First(t *testing.T) {
 	fcn := New("4111 1111 1111 1111")
 	against := "4111"
@@ -167,6 +283,26 @@ func TestInput_First(t *testing.T) {
 	}
 }
 
+func TestInput_FirstError(t *testing.T) {
+	defer func() {
+		if err := recover(); err == nil {
+			t.Errorf("Error expected but got none")
+		}
+	}()
+	fcn := New("4111 1111 1111 1111")
+	fcn.First(100)
+}
+
+func TestInput_LastError(t *testing.T) {
+	defer func() {
+		if err := recover(); err == nil {
+			t.Errorf("Error expected but got none")
+		}
+	}()
+	fcn := New("4111 1111 1111 1111")
+	fcn.Last(100)
+}
+
 func TestInput_Last(t *testing.T) {
 	lcn := New("4111 1111 1111 1348")
 	against := "1348"