Follow these steps to run the test case in debug mode:

1. Open the file /static/tests/colorpicker_tests.js, and update the test QUnit.test with QUnit.only, like this:

...
QUnit.only('int_color field test cases', function (assert) {
...

2. Add the debug parameter in the createView function, as follows:

var form = testUtils.createView({
    View: FormView,
    model: 'book',
    data: this.data,
    arch: '<form string="Books">' +
        '<group>' +
            '<field name="name"/>' +
            '<field name="color" widget="int_color"/>' +
        '</group>' +
        '</form>',
    res_id: 1,
    viewOptions: {
        mode: 'edit',
    },
    debug:1
});

Open the developer mode and open the drop-down menu by clicking on the bug icon on the top menu, then click on Run JS tests. This will open the QUnit suit.