Add tests for NewInput function

errors.go

@@ -39,16 +39,20 @@ const (
 // An InvalidInputError describes an invalid argument passed to Into function
 // The argument must be a non-nil struct pointer
 type InvalidInputError struct {
-	Type  reflect.Type
 	Value reflect.Value
 }
 
 func (e *InvalidInputError) Error() string {
 	msg := "gonfig: invalid input: "
+	var t reflect.Type
 
-	if e.Type == nil {
-		msg += "nil"
-	} else if e.Type.Kind() != reflect.Ptr {
+	if e.Value.IsValid() {
+		t = e.Value.Type()
+	}
+
+	if t == nil {
+		msg += "<nil>"
+	} else if t.Kind() != reflect.Ptr {
 		msg += "non-pointer type"
 	} else if e.Value.IsNil() {
 		msg += "nil pointer"

go.mod

@@ -4,6 +4,9 @@ go 1.15
 
 require (
 	github.com/BurntSushi/toml v0.3.1
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/joho/godotenv v1.3.0
+	github.com/stretchr/testify v1.6.1
 	gopkg.in/yaml.v2 v2.4.0
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 )

go.sum

@@ -1,7 +1,22 @@
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/joho/godotenv v1.3.0 h1:Zjp+RcGpHhGlrMbJzXTrZZPrWj+1vfm90La1wgB6Bhc=
 github.com/joho/godotenv v1.3.0/go.mod h1:7hK45KPybAkOC6peb+G5yklZfMxEjkZhHbwpqxOKXbg=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
+gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

input.go

@@ -39,7 +39,7 @@ type Field struct {
 func NewInput(i interface{}) (*Input, error) {
 	v := reflect.ValueOf(i)
 
-	if err := checkInput(v); err != nil {
+	if err := validateInput(v); err != nil {
 		return nil, err
 	}
 
@@ -52,30 +52,30 @@ func NewInput(i interface{}) (*Input, error) {
 		Tags:  &ConfigTags{},
 	}
 
-	if err := in.traverseFiled(&f); err != nil {
+	if err := in.traverseField(&f); err != nil {
 		return nil, err
 	}
 
 	return &in, nil
 }
 
-// checkInput checks for a non-nil struct pointer
-func checkInput(v reflect.Value) error {
-	if v.Type() == nil ||
+// validateInput checks for a non-nil struct pointer
+func validateInput(v reflect.Value) error {
+	if !v.IsValid() ||
+		v.Type() == nil ||
 		v.Type().Kind() != reflect.Ptr ||
 		v.IsNil() ||
 		v.Type().Elem().Kind() != reflect.Struct {
 		return &InvalidInputError{
-			Type:  v.Type(),
 			Value: v,
 		}
 	}
 
 	return nil
 }
 
-// traverseFiled recursively traverse all fields and collect their information
-func (in *Input) traverseFiled(f *Field) error {
+// traverseField recursively traverse all fields and collect their information
+func (in *Input) traverseField(f *Field) error {
 	if !f.Value.CanSet() || f.Tags.Ignore {
 		return nil
 	}
@@ -95,7 +95,7 @@ func (in *Input) traverseFiled(f *Field) error {
 				Path:  append(f.Path, f.Value.Type().Field(i).Name),
 			}
 
-			if err := in.traverseFiled(&nestedField); err != nil {
+			if err := in.traverseField(&nestedField); err != nil {
 				return err
 			}
 		}
@@ -110,7 +110,7 @@ func (in *Input) traverseFiled(f *Field) error {
 			Path:  f.Path,
 		}
 
-		return in.traverseFiled(&pointedField)
+		return in.traverseField(&pointedField)
 
 	case reflect.Slice, reflect.Array:
 		switch f.Value.Type().Elem().Kind() {