Example tests
- Go course
- Intermediate
- Lesson 45/80
- 4 min
Learn Example functions and output verification.
Example tests
Functions starting with Example are both documentation and tests. The trailing // Output: comment states the expected output; go test compares it, and go doc and pkg.go.dev show the example.
func ExampleTopla() {
fmt.Println(Topla(2, 3))
// Output: 5
}Without an Output line the example is compiled but not run.
Naming rules
An example's name says what it documents: Example() documents the package, ExampleTopla() a function, and ExampleSepet_Ekle() the Ekle method of type Sepet. For several examples of the same item add a lower-case suffix: ExampleTopla_negatif().
Practice Example body
Write the Selam(ad string) string function and an ExampleSelam() function documenting it (with the // Output: Merhaba Ada comment). Call ExampleSelam() in main.
Starter code
package main
import "fmt"
func main() {
// buraya yaz
}Sample solution
package main
import "fmt"
func Selam(ad string) string { return "Merhaba " + ad }
func ExampleSelam() {
fmt.Println(Selam("Ada"))
// Output: Merhaba Ada
}
func main() {
ExampleSelam()
}Expected output
Merhaba Ada
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which is used in an example whose output order is nondeterministic (e.g. iterating a map)?
- No example can be written
- // Unordered output: Correct answer
- // Output:
- // Random:
Explanation: Unordered output compares the lines while ignoring their order.
2 Expected output
func ExampleSelam() {
fmt.Println(Selam("Ada"))
// ____: Merhaba Ada
}func ExampleSelam() {
fmt.Println(Selam("Ada"))
// Output: Merhaba Ada
}Explanation: The // Output: comment states the output go test will compare.
3 Example name
| Term | Meaning |
|---|---|
Example() |
The package |
ExampleTopla() |
The Topla function |
ExampleSepet_Ekle() |
The Sepet.Ekle method |
ExampleTopla_negatif() |
A second example |