diff --git a/openapi2beans/pkg/utils/caseChanging.go b/openapi2beans/pkg/utils/caseChanging.go
index fa22a66..06a49e1 100644
--- a/openapi2beans/pkg/utils/caseChanging.go
+++ b/openapi2beans/pkg/utils/caseChanging.go
@@ -30,6 +30,7 @@ func StringToCamel(inputString string) string {
 	case CAMEL: camelString = inputString
 	case PASCAL: camelString = pascalToCamel(inputString)
 	case SNAKE_VARIANT: camelString = snakeVariantsToCamel(inputString)
+	default: camelString = inputString
 	}
 
 	return camelString
@@ -43,6 +44,7 @@ func StringToPascal(inputString string) string {
 	case CAMEL: pascalString = camelToPascal(inputString)
 	case PASCAL: pascalString = inputString
 	case SNAKE_VARIANT: pascalString = snakeVariantsToPascal(inputString)
+	default: pascalString = inputString
 	}
 
 	return pascalString
@@ -55,6 +57,7 @@ func StringToSnake(inputString string) string {
 	switch stringCase {
 	case CAMEL, PASCAL: snakeString = camelVariantsToSnake(inputString)
 	case SNAKE_VARIANT: snakeString = snakeVariantsToSnake(inputString)
+	default: snakeString = inputString
 	}
 
 	return snakeString
@@ -67,6 +70,7 @@ func StringToScreamingSnake(inputString string) string {
 	switch stringCase {
 	case CAMEL, PASCAL: screamingSnakeString = camelVariantsToScreamingSnake(inputString)
 	case SNAKE_VARIANT: screamingSnakeString = snakeVariantsToScreamingSnake(inputString)
+	default: screamingSnakeString = inputString
 	}
 
 	return screamingSnakeString
@@ -74,7 +78,11 @@ func StringToScreamingSnake(inputString string) string {
 
 // To camel functions
 func pascalToCamel(pascalString string) string {
-	return strings.ToLower(string(pascalString[0])) + pascalString[1:]
+	var camelString string
+	if pascalString != "" {
+		camelString = strings.ToLower(string(pascalString[0])) + pascalString[1:]
+	}
+	return camelString
 }
 
 func snakeVariantsToCamel(snakeString string) string {
@@ -95,7 +103,11 @@ func snakeVariantsToCamel(snakeString string) string {
 
 // To pascal functions
 func camelToPascal(camelString string) string {
-	return strings.ToUpper(string(camelString[0])) + camelString[1:]
+	var pascalString string
+	if camelString != "" {
+		pascalString = strings.ToUpper(string(camelString[0])) + camelString[1:]
+	}
+	return pascalString
 }
 
 func snakeVariantsToPascal(inputString string) string {
@@ -106,14 +118,14 @@ func snakeVariantsToPascal(inputString string) string {
 func camelVariantsToSnake(camelString string) string {
 	var snakeString string
 
-	for _, char := range camelString[1:] {
-		if unicode.IsUpper(char) {
+	for i, char := range camelString {
+		if unicode.IsUpper(char) && i != 0 {
 			snakeString += "_"
 		}
 		snakeString += string(char)
 	}
 
-	return snakeString
+	return strings.ToLower(snakeString)
 }
 
 func snakeVariantsToSnake(inputString string) string {
diff --git a/openapi2beans/pkg/utils/caseChanging_test.go b/openapi2beans/pkg/utils/caseChanging_test.go
index 654b2cf..e089df4 100644
--- a/openapi2beans/pkg/utils/caseChanging_test.go
+++ b/openapi2beans/pkg/utils/caseChanging_test.go
@@ -6,12 +6,192 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestPascalToCamel(t *testing.T) {
+	pascalString := "PascalString"
+	camelString := pascalToCamel(pascalString)
+	assert.Equal(t, "pascalString", camelString)
+
+	pascalString = "P"
+	camelString = pascalToCamel(pascalString)
+	assert.Equal(t, "p", camelString)
+
+	pascalString = ""
+	camelString = pascalToCamel(pascalString)
+	assert.Equal(t, "", camelString)
+
+	pascalString = "9123"
+	camelString = pascalToCamel(pascalString)
+	assert.Equal(t, "9123", camelString)
+}
+
+func TestSnakeVariantsToCamel(t *testing.T) {
+	snakeString := "snake_string"
+	camelString := snakeVariantsToCamel(snakeString)
+	assert.Equal(t, "snakeString", camelString)
+
+	snakeString = "SNAKE_STRING"
+	camelString = snakeVariantsToCamel(snakeString)
+	assert.Equal(t, "snakeString", camelString)
+
+	snakeString = "p"
+	camelString = snakeVariantsToCamel(snakeString)
+	assert.Equal(t, "p", camelString)
+
+	snakeString = ""
+	camelString = snakeVariantsToCamel(snakeString)
+	assert.Equal(t, "", camelString)
+
+	snakeString = "1234"
+	camelString = snakeVariantsToCamel(snakeString)
+	assert.Equal(t, "1234", camelString)
+}
+
+func TestCamelToPascal(t *testing.T) {
+	camelString := "camelString"
+	pascalString := camelToPascal(camelString)
+	assert.Equal(t, "CamelString", pascalString)
+
+	camelString = "c"
+	pascalString = camelToPascal(camelString)
+	assert.Equal(t, "C", pascalString)
+
+	camelString = ""
+	pascalString = camelToPascal(camelString)
+	assert.Equal(t, "", pascalString)
+
+	camelString = "1234"
+	pascalString = camelToPascal(camelString)
+	assert.Equal(t, "1234", pascalString)
+}
+
+func TestSnakeVariantsToPascal(t *testing.T) {
+	snakeString := "snake_string"
+	pascalString := snakeVariantsToPascal(snakeString)
+	assert.Equal(t, "SnakeString", pascalString)
+
+	snakeString = "SNAKE_STRING"
+	pascalString = snakeVariantsToPascal(snakeString)
+	assert.Equal(t, "SnakeString", pascalString)
+
+	snakeString = "p"
+	pascalString = snakeVariantsToPascal(snakeString)
+	assert.Equal(t, "P", pascalString)
+
+	snakeString = ""
+	pascalString = snakeVariantsToPascal(snakeString)
+	assert.Equal(t, "", pascalString)
+
+	snakeString = "1234"
+	pascalString = snakeVariantsToPascal(snakeString)
+	assert.Equal(t, "1234", pascalString)
+}
+
+func TestCamelVariantsToSnake(t *testing.T) {
+	camelString := "camelString"
+	snakeString := camelVariantsToSnake(camelString)
+	assert.Equal(t, "camel_string", snakeString)
+
+	camelString = "PascalString"
+	snakeString = camelVariantsToSnake(camelString)
+	assert.Equal(t, "pascal_string", snakeString)
+
+	camelString = "c"
+	snakeString = camelVariantsToSnake(camelString)
+	assert.Equal(t, "c", snakeString)
+
+	camelString = ""
+	snakeString = camelVariantsToSnake(camelString)
+	assert.Equal(t, "", snakeString)
+
+	camelString = "1234"
+	snakeString = camelVariantsToSnake(camelString)
+	assert.Equal(t, "1234", snakeString)
+}
+
+func TestSnakeVariantsToSnake(t *testing.T) {
+	snakeString := "snake_string"
+	resultingSnake := snakeVariantsToSnake(snakeString)
+	assert.Equal(t, "snake_string", resultingSnake)
+
+	snakeString = "sNaKe_StRiNg"
+	resultingSnake = snakeVariantsToSnake(snakeString)
+	assert.Equal(t, "snake_string", resultingSnake)
+
+	snakeString = "SNAKE_STRING"
+	resultingSnake = snakeVariantsToSnake(snakeString)
+	assert.Equal(t, "snake_string", resultingSnake)
+
+	snakeString = "p"
+	resultingSnake = snakeVariantsToSnake(snakeString)
+	assert.Equal(t, "p", resultingSnake)
+
+	snakeString = ""
+	resultingSnake = snakeVariantsToSnake(snakeString)
+	assert.Equal(t, "", resultingSnake)
+
+	snakeString = "1234"
+	resultingSnake = snakeVariantsToSnake(snakeString)
+	assert.Equal(t, "1234", resultingSnake)
+}
+
+func TestCamelVariantsToScreamingSnake(t *testing.T) {
+	camelString := "camelString"
+	snakeString := camelVariantsToScreamingSnake(camelString)
+	assert.Equal(t, "CAMEL_STRING", snakeString)
+
+	camelString = "PascalString"
+	snakeString = camelVariantsToScreamingSnake(camelString)
+	assert.Equal(t, "PASCAL_STRING", snakeString)
+
+	camelString = "c"
+	snakeString = camelVariantsToScreamingSnake(camelString)
+	assert.Equal(t, "C", snakeString)
+
+	camelString = ""
+	snakeString = camelVariantsToScreamingSnake(camelString)
+	assert.Equal(t, "", snakeString)
+
+	camelString = "1234"
+	snakeString = camelVariantsToScreamingSnake(camelString)
+	assert.Equal(t, "1234", snakeString)
+}
+
+func TestSnakeVariantsToScreamingSnake(t *testing.T) {
+	snakeString := "snake_string"
+	resultingSnake := snakeVariantsToScreamingSnake(snakeString)
+	assert.Equal(t, "SNAKE_STRING", resultingSnake)
+
+	snakeString = "sNaKe_StRiNg"
+	resultingSnake = snakeVariantsToScreamingSnake(snakeString)
+	assert.Equal(t, "SNAKE_STRING", resultingSnake)
+
+	snakeString = "SNAKE_STRING"
+	resultingSnake = snakeVariantsToScreamingSnake(snakeString)
+	assert.Equal(t, "SNAKE_STRING", resultingSnake)
+
+	snakeString = "p"
+	resultingSnake = snakeVariantsToScreamingSnake(snakeString)
+	assert.Equal(t, "P", resultingSnake)
+
+	snakeString = ""
+	resultingSnake = snakeVariantsToScreamingSnake(snakeString)
+	assert.Equal(t, "", resultingSnake)
+
+	snakeString = "1234"
+	resultingSnake = snakeVariantsToScreamingSnake(snakeString)
+	assert.Equal(t, "1234", resultingSnake)
+}
 
 
 func TestStringToCamel(t *testing.T) {
+	// with camel
+	inputCamel := "camelCaseString"
+	camelString := StringToCamel(inputCamel)
+	assert.Equal(t, inputCamel, camelString)
+
 	// with pascal
 	pascalString := "PascalCaseString"
-	camelString := StringToCamel(pascalString)
+	camelString = StringToCamel(pascalString)
 	assert.Equal(t, "pascalCaseString", camelString)
 
 	// with snake
@@ -23,4 +203,74 @@ func TestStringToCamel(t *testing.T) {
 	snakeString = "SNAKE_CASE_STRING"
 	camelString = StringToCamel(snakeString)
 	assert.Equal(t, "snakeCaseString", camelString)
+
+	randomString := "random string with no case >:D"
+	camelString = StringToCamel(randomString)
+	assert.Equal(t, randomString, camelString)
+}
+
+func TestStringToPascal(t *testing.T) {
+	camelString := "thisIsCamel"
+	pascalString := StringToPascal(camelString)
+	assert.Equal(t, "ThisIsCamel", pascalString)
+
+	inputPascal := "ThisIsPascal"
+	pascalString = StringToPascal(inputPascal)
+	assert.Equal(t, inputPascal, pascalString)
+
+	snakeString := "this_is_snake"
+	pascalString = StringToPascal(snakeString)
+	assert.Equal(t, "ThisIsSnake", pascalString)
+
+	snakeString = "THIS_IS_SCREAMING_SNAKE"
+	pascalString = StringToPascal(snakeString)
+	assert.Equal(t, "ThisIsScreamingSnake", pascalString)
+
+	randomString := "random string with no case >:D"
+	pascalString = StringToPascal(randomString)
+	assert.Equal(t, randomString, pascalString)
+}
+
+func TestStringToSnake(t *testing.T) {
+	camelString := "thisIsCamel"
+	snakeString := StringToSnake(camelString)
+	assert.Equal(t, "this_is_camel", snakeString)
+
+	pascalString := "ThisIsPascal"
+	snakeString = StringToSnake(pascalString)
+	assert.Equal(t, "this_is_pascal", snakeString)
+
+	inputSnake := "this_is_snake"
+	snakeString = StringToSnake(inputSnake)
+	assert.Equal(t, inputSnake, snakeString)
+
+	snakeString = "THIS_IS_SCREAMING_SNAKE"
+	snakeString = StringToSnake(snakeString)
+	assert.Equal(t, "this_is_screaming_snake", snakeString)
+
+	randomString := "random string with no case >:D"
+	snakeString = StringToSnake(randomString)
+	assert.Equal(t, randomString, snakeString)
+}
+
+func TestStringToScreamingSnake(t *testing.T) {
+	camelString := "thisIsCamel"
+	screamingSnakeString := StringToScreamingSnake(camelString)
+	assert.Equal(t, "THIS_IS_CAMEL", screamingSnakeString)
+
+	pascalString := "ThisIsPascal"
+	screamingSnakeString = StringToScreamingSnake(pascalString)
+	assert.Equal(t, "THIS_IS_PASCAL", screamingSnakeString)
+
+	snakeString := "this_is_snake"
+	screamingSnakeString = StringToScreamingSnake(snakeString)
+	assert.Equal(t, "THIS_IS_SNAKE", screamingSnakeString)
+
+	inputScreamingSnake := "THIS_IS_SCREAMING_SNAKE"
+	screamingSnakeString = StringToScreamingSnake(inputScreamingSnake)
+	assert.Equal(t, inputScreamingSnake, screamingSnakeString)
+
+	randomString := "random string with no case >:D"
+	screamingSnakeString = StringToScreamingSnake(randomString)
+	assert.Equal(t, randomString, screamingSnakeString)
 }
\ No newline at end of file
diff --git a/openapi2beans/pkg/utils/caseChecking_test.go b/openapi2beans/pkg/utils/caseChecking_test.go
index 095883c..019e404 100644
--- a/openapi2beans/pkg/utils/caseChecking_test.go
+++ b/openapi2beans/pkg/utils/caseChecking_test.go
@@ -183,4 +183,22 @@ func TestIsPascalCase(t *testing.T) {
 	pascalString = "101PascalCase"
 	IsPascal = IsPascalCase(pascalString)
 	assert.True(t, IsPascal)
+}
+
+func TestGetCase(t *testing.T) {
+	testString := "thisIsCamel"
+	stringCase := GetCase(testString)
+	assert.Equal(t, CAMEL, stringCase)
+
+	testString = "ThisIsPascal"
+	stringCase = GetCase(testString)
+	assert.Equal(t, PASCAL, stringCase)
+
+	testString = "this_is_snake"
+	stringCase = GetCase(testString)
+	assert.Equal(t, SNAKE_VARIANT, stringCase)
+
+	testString = "THIS_IS_SCREAMING_SNAKE"
+	stringCase = GetCase(testString)
+	assert.Equal(t, SNAKE_VARIANT, stringCase)
 }
\ No newline at end of file