in upgradetest.go [138:144]
func diffTwoVersions(t *T, opts terraform.Options, originTerraformDir string, newModulePath string) error {
opts.TerraformDir = originTerraformDir
defer destroy(t, opts)
initAndApply(t, &opts)
overrideModuleSourceToCurrentPath(t, originTerraformDir, newModulePath)
return initAndPlanAndIdempotentAtEasyMode(t, opts)
}