Trying to run tests in parallel with suite fails

[pantelis-karamolegkos]

I have several tests using testify/suite and I execute them in parallel as follows

type IntegrationSuite struct {
	suite.Suite
}

func TestIntegrationSuite(t *testing.T) {
	suite.Run(t, &IntegrationSuite{})
}

func (is *IntegrationSuite) TestSomething() {
	is.T().Log("\tIntegration Testing something")
	for i := range myTestTable {
		i := i
		is.T().Run("Testing "+myTestTable[i].scenarioName, func(_ *testing.T) {
			is.T().Parallel()
...

func (is *IntegrationSuite) TestSomethingElse() {
	is.T().Log("\tIntegration Testing something else")
	for i := range myOtherTestTable {
		i := i
		is.T().Run("Testing "+myOtherTestTable[i].scenarioName, func(_ *testing.T) {
			is.T().Parallel()
...
		})

However this panics with

panic: testing: t.Parallel called multiple times [recovered]
        panic: testing: t.Parallel called multiple times

[brackendawson]

This happens because the value returned by is.T() is the *testing.T for the test, not for the subtest.

Maybe not a dupe but related to to #187, I think #1109 would fix this.

[Antonboom]

@brackendawson, hi!

I found that the pattern

s.T().Run("subtest", func(t *testing.T) {
    t.Parallel()
})

works fine (test).

But this is incompatible with any s.Run in the same test and generally encourages people to avoid s.Run, although I consider it best practice (Antonboom/testifylint#104)

What do you think is the example above valid? Or just black magic? Or I missed something?
Thanks

[dolmen]

@Antonboom Users are expecting AfterTest to run after test. We can't can't guarantee that if the test runs in another goroutine because it is Parallel.

So at this point, as a maintainer, it is safer to just discourage using Parallel subtests.