Impacted versions:

**11.0**

Steps to reproduce:

Install a new db with demo data, and sale_stock module.  Set rounding for product unit of measure from 3 to 5.  Run sale_stock tests (from command line with --test-enable)

Current behavior:

> FAIL: test_02_sale_stock_return (odoo.addons.sale_stock.tests.test_sale_stock.TestSaleStock)
> 
> AssertionError: 3.0000000000000004 != 3.0 : Sale Stock: delivered quantity should be 3.0 instead of "3.0000000000000004" after picking return
> 

At the lowest level, it appears that float_round is called by  convert_to_cache.

- **float_round(3.0, precision_digits=x) == 3.0**, if x is 1, 2, 3, 4, 6, 7, 8, 9, 10
- **float_round(3.0, precision_digits=5) == 3.0000000000000004**



"""
        Test a SO with a product invoiced on delivery. Deliver partially and invoice the SO, when
        the SO is set on 'done', the SO should be fully invoiced.
        """
        
        self.partner = self.env.ref('base.res_partner_1')
        self.product = self.env.ref('product.product_delivery_01')
        so_vals = {
            'partner_id': self.partner.id,
            'partner_invoice_id': self.partner.id,
            'partner_shipping_id': self.partner.id,
            'order_line': [(0, 0, {
                'name': self.product.name,
                'product_id': self.product.id,
                'product_uom_qty': 5.0,
                'product_uom': self.product.uom_id.id,