I've the following function which getting a file and write content to it.
func setFile(file *os.File, appStr models.App) {
file.WriteString("1.0")
file.WriteString("Created-By: application generation process")
for _, mod := range appStr.Modules {
file.WriteString(NEW_LINE)
file.WriteString(NEW_LINE)
file.WriteString("Application")
file.WriteString(NEW_LINE)
file.WriteString("ApplicationContent")
file.WriteString(NEW_LINE)
file.WriteString("ContentType")
}
}
For that I generate a unit test like following
func Test_setFile(t *testing.T) {
type args struct {
file *os.File
appStr models.App
}
var tests []struct {
name string
args args
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
setFile(tt.args.file, tt.args.AppStr)
})
}
}
The problem here is that im depending on file, what is better approach to create unit test for this kind of function
The better approach would be to accept an interface, something like io.Writer. In your real usage you can pass in a *os.File, and in your tests you can pass in something easier to work with like a bytes.Buffer.
Something like (untested but should get you started):
func setFile(file io.Writer, appStr models.App) {
fmt.Fprint(file, "1.0")
fmt.Fprint(file, "Created-By: application generation process")
for _, mod := range appStr.Modules {
fmt.Fprint(file, NEW_LINE)
fmt.Fprint(file, NEW_LINE)
fmt.Fprint(file, "Application")
fmt.Fprint(file, NEW_LINE)
fmt.Fprint(file, "ApplicationContent")
fmt.Fprint(file, NEW_LINE)
fmt.Fprint(file, "ContentType")
}
}
func Test_setFile(t *testing.T) {
type args struct {
appStr models.App
}
var tests []struct {
name string
args args
expected []byte
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
b := &bytes.Buffer{}
setFile(b, tt.args.AppStr)
if !bytes.Equal(b.Bytes(), tt.expected) {
t.Error("somewhat bad happen")
}
})
}
}