Change user permission by using a new apply button (#12346)

* Add PowerLevelSelector.tsx.
It's extracting the current behavior of the privileged users and muted of `RolesRoomSettingsTab.tsx` into a dedicated component.
It's also adding a new apply button.

* Use `PowerLevelSelector` to render privileged and muted users in `RolesRoomSettingsTab`

* Update existing tests

* Add playwright test

* Fix typo

* Fix typo

test/components/views/settings/PowerLevelSelector-test.tsx

@@ -0,0 +1,120 @@
+/*
+ *
+ * Copyright 2024 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * /
+ */
+
+import { render, screen } from "@testing-library/react";
+import React, { ComponentProps } from "react";
+import userEvent from "@testing-library/user-event";
+
+import { PowerLevelSelector } from "../../../../src/components/views/settings/PowerLevelSelector";
+import { stubClient } from "../../../test-utils";
+import MatrixClientContext from "../../../../src/contexts/MatrixClientContext";
+
+describe("PowerLevelSelector", () => {
+    const matrixClient = stubClient();
+
+    const currentUser = matrixClient.getUserId()!;
+    const userLevels = {
+        [currentUser]: 100,
+        "@alice:server.org": 50,
+        "@bob:server.org": 0,
+    };
+
+    const renderPLS = (props: Partial<ComponentProps<typeof PowerLevelSelector>>) =>
+        render(
+            <MatrixClientContext.Provider value={matrixClient}>
+                <PowerLevelSelector
+                    userLevels={userLevels}
+                    canChangeLevels={true}
+                    currentUserLevel={userLevels[currentUser]}
+                    title="title"
+                    // filter nothing by default
+                    filter={() => true}
+                    onClick={jest.fn()}
+                    {...props}
+                >
+                    empty label
+                </PowerLevelSelector>
+            </MatrixClientContext.Provider>,
+        );
+
+    it("should render", () => {
+        renderPLS({});
+        expect(screen.getByRole("group")).toMatchSnapshot();
+    });
+
+    it("should display only the current user", async () => {
+        // Display only the current user
+        renderPLS({ filter: (user) => user === currentUser });
+
+        // Only alice should be displayed
+        const userSelects = screen.getAllByRole("combobox");
+        expect(userSelects).toHaveLength(1);
+        expect(userSelects[0]).toHaveAccessibleName(currentUser);
+
+        expect(screen.getByRole("group")).toMatchSnapshot();
+    });
+
+    it("should be able to change the power level of the current user", async () => {
+        const onClick = jest.fn();
+        renderPLS({ onClick });
+
+        // Until the power level is changed, the apply button should be disabled
+        // compound button is using aria-disabled instead of the disabled attribute, we can't toBeDisabled on it
+        expect(screen.getByRole("button", { name: "Apply" })).toHaveAttribute("aria-disabled", "true");
+
+        const select = screen.getByRole("combobox", { name: currentUser });
+        // Sanity check
+        expect(select).toHaveValue("100");
+
+        // Change current user power level to 50
+        await userEvent.selectOptions(select, "50");
+        expect(select).toHaveValue("50");
+        // After the user level changes, the apply button should be enabled
+        expect(screen.getByRole("button", { name: "Apply" })).toHaveAttribute("aria-disabled", "false");
+
+        // Click on Apply should call onClick with the new power level
+        await userEvent.click(screen.getByRole("button", { name: "Apply" }));
+        expect(onClick).toHaveBeenCalledWith(50, currentUser);
+    });
+
+    it("should not be able to change the power level if `canChangeLevels` is false", async () => {
+        renderPLS({ canChangeLevels: false });
+
+        // The selects should be disabled
+        const userSelects = screen.getAllByRole("combobox");
+        userSelects.forEach((select) => expect(select).toBeDisabled());
+    });
+
+    it("should be able to change only the level of someone with a lower level", async () => {
+        const userLevels = {
+            [currentUser]: 50,
+            "@alice:server.org": 100,
+        };
+        renderPLS({ userLevels });
+
+        expect(screen.getByRole("combobox", { name: currentUser })).toBeEnabled();
+        expect(screen.getByRole("combobox", { name: "@alice:server.org" })).toBeDisabled();
+    });
+
+    it("should display the children if there is no user to display", async () => {
+        // No user to display
+        renderPLS({ filter: () => false });
+
+        expect(screen.getByText("empty label")).toBeInTheDocument();
+    });
+});