public async Task AssignRoleToUserAsync_RequestNull_ThrowArgumentNullException()
{
// Arrange
UserRoleAssignmentRequest request = null;
// Act + Assert
ArgumentNullException exception = await Assert.ThrowsAsync <ArgumentNullException>(() =>
_identityService.AssignRoleToUserAsync(request)).ConfigureAwait(false);
Assert.NotNull(exception);
Assert.Equal(string.Format(ErrorMessages.NullExceptionMessage, "request"), exception.Message);
}
