[DataGrid] Allow passing styles and Popper props to GridPanel

[sebastianfrey]

Closes #1808.

[oliviertassinari]

A good opportunity to add a describeConformance test for this component.

[sebastianfrey]

Where should I place the test? Inside packages/grid/data-grid/src/tests/components.DataGrid.test.tsx?

[oliviertassinari]

Where should I place the test?

Where it optimizes for removing code: /packages/grid/_modules_/grid/components/panel/GridPanel.test.tsx.

[oliviertassinari]

I have polished the PR. It should be OK now. In the future, we will likely need to add a components and componentsProps props to this component.

[sebastianfrey]

Thanks for the update. Since I had to do some priority tasks in my day to day job, I have not yet got around to write some tests.

[oliviertassinari]

I have already added a TypeScript test case. I'm adding a describe conformance, we have never used this before, time to introduce it.

[sebastianfrey]

@oliviertassinari Ah, sry for pushing my test.. I did not read your answer in time.

[flaviendelangle]

https://app.circleci.com/pipelines/github/mui-org/material-ui-x/6058/workflows/52b8b247-8918-418a-831f-3440e0e27acb/jobs/31886

@oliviertassinari getClasses has been removed on this commit mui/material-ui@2569eb9#diff-f075d81b14df1f31fb0699c4516fe3d78490351867feeb4fb869d5dbe8c6128e

On the core, they are directly importing the classes for the component file (like we want to do in #1950)
But in the meantime do we have a better solution than copy/paste the getClasses that used to be in the core in our repo ?

[oliviertassinari]

@flaviendelangle I see, we got a conflict between #1994 and #2114, that broke master. getClasses is a trivial helper, we can add it back with a "TODO v5 remove" or similar.