Test function
- Go course
- Intermediate
- Lesson 41/80
- 4 min
Learn the func TestXxx signature and the go test command.
Test functions
In Go, tests are written in files ending with _test.go and run with go test. A test function starts with Test and takes a *testing.T:
// topla_test.go
package hesap
import "testing"
func TestTopla(t *testing.T) {
if got := Topla(2, 3); got != 5 {
t.Errorf("Topla(2, 3) = %d, beklenen 5", got)
}
}There is no separate test framework; the standard testing package is enough.
go test flags
Commonly used flags:
go test ./... # all packages
go test -v -run TestTopla # verbose, tests matching the name
go test -race ./... # data race detection
go test -cover ./... # coverage
go test -count=1 ./... # skip the cacheTests can access the package's internal functions; to look from outside, use package hesap_test.
Practice Mini test runner
Imitate the essence of a test: write Topla(a, b int) int. In main, compute got := Topla(2, 3) and print "FAIL" if got != 5, otherwise "PASS".
Starter code
package main
import "fmt"
func main() {
// buraya yaz
}Sample solution
package main
import "fmt"
func Topla(a, b int) int { return a + b }
func main() {
if got := Topla(2, 3); got != 5 {
fmt.Println("FAIL")
return
}
fmt.Println("PASS")
}Expected output
PASS
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which function does <code>go test</code> run as a test?
- func TestToplam()
- func TestToplam(t *testing.T) Correct answer
- func testToplam(t *testing.T)
- func Testtoplam(t *testing.T)
Explanation: The name must start with Test followed by an upper-case letter (or nothing), and the only parameter must be *testing.T.
2 Test file
// topla____.go
package hesap// topla_test.go
package hesapExplanation: go test only builds and runs tests in files ending with _test.go.
3 Flag and effect
| Term | Meaning |
|---|---|
-v |
Verbose output |
-run |
Filter by name |
-race |
Race detection |
-cover |
Coverage |