サンプルで学ぶ Go 言語：Testing
|
Unit testing is an important part of writing
principled Go programs. The |
|
|
For the sake of demonstration, this code is in package
|
 
package main
|
import (
"fmt"
"testing"
)
|
|
|
We’ll be testing this simple implementation of an
integer minimum. Typically, the code we’re testing
would be in a source file named something like
|
func IntMin(a, b int) int {
if a < b {
return a
}
return b
}
|
|
A test is created by writing a function with a name
beginning with |
func TestIntMinBasic(t *testing.T) {
ans := IntMin(2, -2)
if ans != -2 {
|
|
|
t.Errorf("IntMin(2, -2) = %d; want -2", ans)
}
}
|
|
Writing tests can be repetitive, so it’s idiomatic to use a table-driven style, where test inputs and expected outputs are listed in a table and a single loop walks over them and performs the test logic. |
func TestIntMinTableDriven(t *testing.T) {
var tests = []struct {
a, b int
want int
}{
{0, 1, 0},
{1, 0, 0},
{2, -2, -2},
{0, -1, -1},
{-1, 0, -1},
}
|
|
t.Run enables running “subtests”, one for each
table entry. These are shown separately
when executing |
for _, tt := range tests {
|
testname := fmt.Sprintf("%d,%d", tt.a, tt.b)
t.Run(testname, func(t *testing.T) {
ans := IntMin(tt.a, tt.b)
if ans != tt.want {
t.Errorf("got %d, want %d", ans, tt.want)
}
})
}
}
|
|
Run all tests in the current project in verbose mode. |
$ go test -v
== RUN TestIntMinBasic
--- PASS: TestIntMinBasic (0.00s)
=== RUN TestIntMinTableDriven
=== RUN TestIntMinTableDriven/0,1
=== RUN TestIntMinTableDriven/1,0
=== RUN TestIntMinTableDriven/2,-2
=== RUN TestIntMinTableDriven/0,-1
=== RUN TestIntMinTableDriven/-1,0
--- PASS: TestIntMinTableDriven (0.00s)
--- PASS: TestIntMinTableDriven/0,1 (0.00s)
--- PASS: TestIntMinTableDriven/1,0 (0.00s)
--- PASS: TestIntMinTableDriven/2,-2 (0.00s)
--- PASS: TestIntMinTableDriven/0,-1 (0.00s)
--- PASS: TestIntMinTableDriven/-1,0 (0.00s)
PASS
ok examples/testing 0.023s
|