$PasswordProfile = New-Object -TypeName Microsoft.Open.AzureAD.Model.PasswordProfile
$PasswordProfile.Password = "<Password>"
$PasswordProfile.EnforceChangePasswordPolicy = $True
New-AzureADUser -DisplayName "<Display Name of User>" -PasswordProfile $PasswordProfile -UserPrincipalName "<developer's test user>@dosinvest.onmicrosoft.com" -AccountEnabled $true -MailNickName "<NickName to use for Mail name>"
$username = "<developer's test user>@dosinvest.onmicrosoft.com"
$app_name = "<Name of Application>"
$app_role_name = "<Display Name of Role within Application>"
$user = Get-AzureADUser -ObjectId "$username"
$sp = Get-AzureADServicePrincipal -Filter "displayName eq '$app_name'"
$appRole = $sp.AppRoles | Where-Object { $_.DisplayName -eq $app_role_name }
New-AzureADUserAppRoleAssignment -ObjectId $user.ObjectId -PrincipalId $user.ObjectId -ResourceId $sp.ObjectId -Id $appRole.Id