How to solve deadlock(waiting for singal from a failed test)

Question

I have two goroutines which are two TestXxx functions during the testing. I use a conditional variable to synchronize these goroutines. However, once one of them fails the test while the other one is waiting for the signal. Here comes a deadlock. Also, I want TestFunctionA to be failed if TestFunctionB is failed.

var cond sync.Cond
func TestFunctionA(t *testing.T){
   // ... Some codes...
   cond.Wait()
}
func TestFunctionB(t *testing.T){
   // ... Some codes...
   t.Fail()
   // ... Some codes...
   cond.Broadcast()
}

I've tried some ways, for example:

var cond sync.Cond
var A_t *testing.T
func TestFunctionA(t *testing.T){
   // ... Some codes...
   A_t = t
   // ... Some codes...
   cond.Wait()
}
func TestFunctionB(t *testing.T){
   // ... Some codes...
   t.Cleanup(func(){
      if !A_t.Failed(){
          A_t.Fail()
      }
      cond.Broadcast()
   })
   t.Fail()
   // ... Some codes...
   cond.Broadcast()
}

But the A_t.Fail() is still triggered when there is no error in FunctionB.

And I'm also considering using context.Context(). However, I have no idea how to run a Testfunction with a context. Thank you for reading my question! I appreciate any comment or discussion!

Answer 1

A test should not interact with another test. But we can share anything between test cases when using subtests.

Here is an example:

package main

import (
    "errors"
    "testing"
)

func TestFruits(t *testing.T) {
    var err error
    t.Run("test apple", getTestAppleFunc(&err))
    t.Run("test banana", getTestBananaFunc(&err))
}

func handleError(t *testing.T, err *error) {
    if err != nil && *err != nil {
        t.Error(*err)
    }
}

func getTestAppleFunc(err *error) func(*testing.T) {
    return func(t *testing.T) {
        handleError(t, err)
        *err = errors.New("Apple failed")
    }
}

func getTestBananaFunc(err *error) func(*testing.T) {
    return func(t *testing.T) {
        handleError(t, err)
    }
}

• In the functions getTestBananaFunc and getTestAppleFunc, the pointer of error is passed as an argument.
• In the above example, getTestAppleFunc is executed first.
• If an error is assigned in getTestAppleFunc, as shown in the above example, the getTestBananaFunc function will fail.