Example tests

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().

Exercise 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.

Show example 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()
}

Test yourself

Which is used in an example whose output order is nondeterministic (e.g. iterating a map)?
- No example can be written
- // Unordered output:
- // Output:
- // Random:
Show answer

// Unordered output: — Unordered output compares the lines while ignoring their order.

Expected output

func ExampleSelam() {
    fmt.Println(Selam("Ada"))
    // ____: Merhaba Ada
}

Show answer

func ExampleSelam() {
    fmt.Println(Selam("Ada"))
    // Output: Merhaba Ada
}

Example name

Example()

The package
ExampleTopla()

The Topla function
ExampleSepet_Ekle()

The Sepet.Ekle method
ExampleTopla_negatif()

A second example

Next lesson: Summary - Testing

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