Question

将测试函数拆分为子测试，更符合套件（suite）模式。

• 便于编写初始化（setup）和清理（teardown）逻辑。
• 表驱动（table driven）时，拆分成多个并发测试。
• 便于观察子测试时间，不用考虑外部环境影响。

func TestA(t *testing.T) {
	time.Sleep(time.Second)
}

func TestB(t *testing.T) {
	time.Sleep(time.Second)
}

func TestC(t *testing.T) {
	time.Sleep(time.Second)
}

func TestSuite(t *testing.T) {
	t.Log("setup")
	defer t.Log("teardown")

	t.Run("A", TestA)
	t.Run("B", TestB)
	t.Run("C", TestC)
}

$ go test -v -run "Suite"

=== RUN   TestSuite

    main_test.go:21: setup
    
=== RUN   TestSuite/A
=== RUN   TestSuite/B
=== RUN   TestSuite/C

=== CONT  TestSuite

    main_test.go:27: teardown
    
--- PASS: TestSuite (3.02s)
    --- PASS: TestSuite/A (1.01s)
    --- PASS: TestSuite/B (1.00s)
    --- PASS: TestSuite/C (1.00s)
    
PASS
ok  	test	3.028s

# 按名称单独执行子测试。

$ go test -v -run "Suite/[AB]"
$ go test -v -run "Suite/B"

支持子测试并行。

func TestSuite(t *testing.T) {
	tests := []int{1, 2}
    
    for v := range tests {
        
        // 避开闭包延迟。
        x := v
        
        t.Run("", func(t *testing.T) {
            t.Parallel()
            time.Sleep(time.Second * 5)
            println(x)
        })
    }
}

前文提过， Parallel 挂起当前测试，让 Run 提前退出。
上例中有 teardown 的话，会在子测试结束前执行。

func TestSuite(t *testing.T) {
	tests := []int{1, 2}

	defer t.Log("teardown")
    
    for v := range tests {
		x := v
        
		t.Run("", func(t *testing.T) {
			t.Parallel()
			time.Sleep(time.Second * 5)
			println(x)
		})
	}
}

$ go test -v -run "Suite"

=== RUN   TestSuite
=== RUN   TestSuite/#00
=== PAUSE TestSuite/#00
=== RUN   TestSuite/#01
=== PAUSE TestSuite/#01
=== CONT  TestSuite

main_test.go:31: teardown

=== CONT  TestSuite/#00
=== CONT  TestSuite/#01

1
0

--- PASS: TestSuite (0.00s)
--- PASS: TestSuite/#01 (5.01s)
--- PASS: TestSuite/#00 (5.01s)

PASS
ok  	test	5.014s

解决办法，就是在外面再套一个 Run 调用。

func TestSuite(t *testing.T) {
	tests := []int{1, 2}

    defer t.Log("teardown")
    
    // 不受影响。
    t.Run("group", func(t *testing.T) {
        for v := range tests {
            x := v
            
            // 因 Parallel 提前退出。
            t.Run("", func(t *testing.T) {
                t.Parallel()
                time.Sleep(time.Second * 5)
                println(x)
            })
        }
    })
}

$ go test -v -run "Suite"

=== RUN   TestSuite
=== RUN   TestSuite/group
=== RUN   TestSuite/group/#00
=== PAUSE TestSuite/group/#00
=== RUN   TestSuite/group/#01
=== PAUSE TestSuite/group/#01
=== CONT  TestSuite/group/#00
=== CONT  TestSuite/group/#01

0
1

=== CONT  TestSuite

    main_test.go:21: teardown
    
--- PASS: TestSuite (5.01s)
    --- PASS: TestSuite/group (0.01s)
        --- PASS: TestSuite/group/#00 (5.00s)
        --- PASS: TestSuite/group/#01 (5.00s)
        
PASS
ok  	test	5.019s