Display and send votes in polls (#7158)

Co-authored-by: Travis Ralston <travpc@gmail.com>

res/css/views/messages/_MPollBody.scss

@@ -86,6 +86,12 @@ limitations under the License.
 
     .mx_MPollBody_option_checked {
         border-color: $accent;
+
+        .mx_MPollBody_popularityBackground {
+            .mx_MPollBody_popularityAmount {
+                background-color: $accent;
+            }
+        }
     }
 
     .mx_StyledRadioButton_checked input[type="radio"] + div {

src/components/views/messages/IBodyProps.ts

@@ -14,11 +14,12 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { MatrixEvent } from "matrix-js-sdk/src";
+import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 import { TileShape } from "../rooms/EventTile";
 import { MediaEventHelper } from "../../../utils/MediaEventHelper";
 import EditorStateTransfer from "../../../utils/EditorStateTransfer";
 import { RoomPermalinkCreator } from "../../../utils/permalinks/Permalinks";
+import { Relations } from "matrix-js-sdk/src/models/relations";
 
 export interface IBodyProps {
     mxEvent: MatrixEvent;
@@ -41,4 +42,7 @@ export interface IBodyProps {
     onMessageAllowed: () => void; // TODO: Docs
     permalinkCreator: RoomPermalinkCreator;
     mediaEventHelper: MediaEventHelper;
+
+    // helper function to access relations for this event
+    getRelationsForEvent?: (eventId: string, relationType: string, eventType: string) => Relations;
 }

src/components/views/messages/MPollBody.tsx

@@ -18,14 +18,24 @@ import React from 'react';
 import { _t } from '../../../languageHandler';
 import { replaceableComponent } from "../../../utils/replaceableComponent";
 import { IBodyProps } from "./IBodyProps";
-import { IPollAnswer, IPollContent, POLL_START_EVENT_TYPE } from '../../../polls/consts';
+import {
+    IPollAnswer,
+    IPollContent,
+    IPollResponse,
+    POLL_RESPONSE_EVENT_TYPE,
+    POLL_START_EVENT_TYPE,
+} from '../../../polls/consts';
 import StyledRadioButton from '../elements/StyledRadioButton';
+import { MatrixEvent } from "matrix-js-sdk/src/models/event";
+import { Relations } from 'matrix-js-sdk/src/models/relations';
+import { MatrixClientPeg } from '../../../MatrixClientPeg';
 
 // TODO: [andyb] Use extensible events library when ready
 const TEXT_NODE_TYPE = "org.matrix.msc1767.text";
 
 interface IState {
     selected?: string;
+    pollRelations: Relations;
 }
 
 @replaceableComponent("views.messages.MPollBody")
@@ -33,12 +43,88 @@ export default class MPollBody extends React.Component<IBodyProps, IState> {
     constructor(props: IBodyProps) {
         super(props);
 
-        this.state = {
-            selected: null,
-        };
+        const pollRelations = this.fetchPollRelations();
+        let selected = null;
+
+        const userVotes = collectUserVotes(allVotes(pollRelations), null);
+        const userId = MatrixClientPeg.get().getUserId();
+        const currentVote = userVotes.get(userId);
+        if (currentVote) {
+            selected = currentVote.answers[0];
+        }
+
+        this.state = { selected, pollRelations };
+
+        this.addListeners(this.state.pollRelations);
+        this.props.mxEvent.on("Event.relationsCreated", this.onPollRelationsCreated);
     }
 
+    componentWillUnmount() {
+        this.props.mxEvent.off("Event.relationsCreated", this.onPollRelationsCreated);
+        this.removeListeners(this.state.pollRelations);
+    }
+
+    private addListeners(pollRelations?: Relations) {
+        if (pollRelations) {
+            pollRelations.on("Relations.add", this.onRelationsChange);
+            pollRelations.on("Relations.remove", this.onRelationsChange);
+            pollRelations.on("Relations.redaction", this.onRelationsChange);
+        }
+    }
+
+    private removeListeners(pollRelations?: Relations) {
+        if (pollRelations) {
+            pollRelations.off("Relations.add", this.onRelationsChange);
+            pollRelations.off("Relations.remove", this.onRelationsChange);
+            pollRelations.off("Relations.redaction", this.onRelationsChange);
+        }
+    }
+
+    private onPollRelationsCreated = (relationType: string, eventType: string) => {
+        if (
+            relationType === "m.reference" &&
+            POLL_RESPONSE_EVENT_TYPE.matches(eventType)
+        ) {
+            this.props.mxEvent.removeListener(
+                "Event.relationsCreated", this.onPollRelationsCreated);
+
+            const newPollRelations = this.fetchPollRelations();
+            this.addListeners(newPollRelations);
+            this.removeListeners(this.state.pollRelations);
+
+            this.setState({
+                pollRelations: newPollRelations,
+            });
+        }
+    };
+
+    private onRelationsChange = () => {
+        // We hold pollRelations in our state, and it has changed under us
+        this.forceUpdate();
+    };
+
     private selectOption(answerId: string) {
+        if (answerId === this.state.selected) {
+            return;
+        }
+
+        const responseContent: IPollResponse = {
+            [POLL_RESPONSE_EVENT_TYPE.name]: {
+                "answers": [answerId],
+            },
+            "m.relates_to": {
+                "event_id": this.props.mxEvent.getId(),
+                "rel_type": "m.reference",
+            },
+        };
+        MatrixClientPeg.get().sendEvent(
+            this.props.mxEvent.getRoomId(),
+            POLL_RESPONSE_EVENT_TYPE.name,
+            responseContent,
+        ).catch(e => {
+            console.error("Failed to submit poll response event:", e);
+        });
+
         this.setState({ selected: answerId });
     }
 
@@ -46,20 +132,60 @@ export default class MPollBody extends React.Component<IBodyProps, IState> {
         this.selectOption(e.currentTarget.value);
     };
 
+    private fetchPollRelations(): Relations | null {
+        if (this.props.getRelationsForEvent) {
+            return this.props.getRelationsForEvent(
+                this.props.mxEvent.getId(),
+                "m.reference",
+                POLL_RESPONSE_EVENT_TYPE.name,
+            );
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * @returns answer-id -> number-of-votes
+     */
+    private collectVotes(): Map<string, number> {
+        return countVotes(
+            collectUserVotes(allVotes(this.state.pollRelations), this.state.selected),
+            this.props.mxEvent.getContent(),
+        );
+    }
+
+    private totalVotes(collectedVotes: Map<string, number>): number {
+        let sum = 0;
+        for (const v of collectedVotes.values()) {
+            sum += v;
+        }
+        return sum;
+    }
+
     render() {
-        const pollStart: IPollContent =
-            this.props.mxEvent.getContent()[POLL_START_EVENT_TYPE.name];
+        const pollStart: IPollContent = this.props.mxEvent.getContent();
+        const pollInfo = pollStart[POLL_START_EVENT_TYPE.name];
+
+        if (pollInfo.answers.length < 1 || pollInfo.answers.length > 20) {
+            return null;
+        }
+
         const pollId = this.props.mxEvent.getId();
+        const votes = this.collectVotes();
+        const totalVotes = this.totalVotes(votes);
 
         return <div className="mx_MPollBody">
-            <h2>{ pollStart.question[TEXT_NODE_TYPE] }</h2>
+            <h2>{ pollInfo.question[TEXT_NODE_TYPE] }</h2>
             <div className="mx_MPollBody_allOptions">
                 {
-                    pollStart.answers.map((answer: IPollAnswer) => {
+                    pollInfo.answers.map((answer: IPollAnswer) => {
                         const checked = this.state.selected === answer.id;
                         const classNames = `mx_MPollBody_option${
                             checked ? " mx_MPollBody_option_checked": ""
                         }`;
+                        const answerVotes = votes.get(answer.id) ?? 0;
+                        const answerPercent = Math.round(
+                            100.0 * answerVotes / totalVotes);
                         return <div
                             key={answer.id}
                             className={classNames}
@@ -72,22 +198,116 @@ export default class MPollBody extends React.Component<IBodyProps, IState> {
                                 onChange={this.onOptionSelected}
                             >
                                 <div className="mx_MPollBody_optionVoteCount">
-                                    { _t("%(number)s votes", { number: 0 }) }
+                                    { _t("%(count)s votes", { count: answerVotes }) }
                                 </div>
                                 <div className="mx_MPollBody_optionText">
                                     { answer[TEXT_NODE_TYPE] }
                                 </div>
                             </StyledRadioButton>
                             <div className="mx_MPollBody_popularityBackground">
-                                <div className="mx_MPollBody_popularityAmount" />
+                                <div
+                                    className="mx_MPollBody_popularityAmount"
+                                    style={{ "width": `${answerPercent}%` }}
+                                />
                             </div>
                         </div>;
                     })
                 }
             </div>
             <div className="mx_MPollBody_totalVotes">
-                { _t( "Based on %(total)s votes", { total: 0 } ) }
+                { _t( "Based on %(count)s votes", { count: totalVotes } ) }
             </div>
         </div>;
     }
 }
+
+export class UserVote {
+    constructor(public readonly ts: number, public readonly sender: string, public readonly answers: string[]) {
+    }
+}
+
+function userResponseFromPollResponseEvent(event: MatrixEvent): UserVote {
+    const pr = event.getContent() as IPollResponse;
+    const answers = pr[POLL_RESPONSE_EVENT_TYPE.name].answers;
+
+    return new UserVote(
+        event.getTs(),
+        event.getSender(),
+        answers,
+    );
+}
+
+export function allVotes(pollRelations: Relations): Array<UserVote> {
+    function isPollResponse(responseEvent: MatrixEvent): boolean {
+        return (
+            responseEvent.getType() === POLL_RESPONSE_EVENT_TYPE.name &&
+            responseEvent.getContent().hasOwnProperty(POLL_RESPONSE_EVENT_TYPE.name)
+        );
+    }
+
+    if (pollRelations) {
+        return pollRelations.getRelations()
+            .filter(isPollResponse)
+            .map(userResponseFromPollResponseEvent);
+    } else {
+        return [];
+    }
+}
+
+/**
+ * Figure out the correct vote for each user.
+ * @returns a Map of user ID to their vote info
+ */
+function collectUserVotes(
+    userResponses: Array<UserVote>,
+    selected?: string,
+): Map<string, UserVote> {
+    const userVotes: Map<string, UserVote> = new Map();
+
+    for (const response of userResponses) {
+        const otherResponse = userVotes.get(response.sender);
+        if (!otherResponse || otherResponse.ts < response.ts) {
+            userVotes.set(response.sender, response);
+        }
+    }
+
+    if (selected) {
+        const client = MatrixClientPeg.get();
+        const userId = client.getUserId();
+        userVotes.set(userId, new UserVote(0, userId, [selected]));
+    }
+
+    return userVotes;
+}
+
+function countVotes(
+    userVotes: Map<string, UserVote>,
+    pollStart: IPollContent,
+): Map<string, number> {
+    const collected = new Map<string, number>();
+
+    const pollInfo = pollStart[POLL_START_EVENT_TYPE.name];
+    const maxSelections = 1;  // See MSC3381 - later this will be in pollInfo
+
+    const allowedAnswerIds = pollInfo.answers.map((ans: IPollAnswer) => ans.id);
+    function isValidAnswer(answerId: string) {
+        return allowedAnswerIds.includes(answerId);
+    }
+
+    for (const response of userVotes.values()) {
+        if (response.answers.every(isValidAnswer)) {
+            for (const [index, answerId] of response.answers.entries()) {
+                if (index >= maxSelections) {
+                    break;
+                }
+                if (collected.has(answerId)) {
+                    collected.set(answerId, collected.get(answerId) + 1);
+                } else {
+                    collected.set(answerId, 1);
+                }
+            }
+        }
+    }
+
+    return collected;
+}

src/components/views/messages/MessageEvent.tsx

@@ -28,12 +28,16 @@ import { ReactAnyComponent } from "../../../@types/common";
 import { EventType, MsgType } from "matrix-js-sdk/src/@types/event";
 import { IBodyProps } from "./IBodyProps";
 import { POLL_START_EVENT_TYPE } from '../../../polls/consts';
+import { Relations } from 'matrix-js-sdk/src/models/relations';
 
 // onMessageAllowed is handled internally
 interface IProps extends Omit<IBodyProps, "onMessageAllowed"> {
     /* overrides for the msgtype-specific components, used by ReplyTile to override file rendering */
     overrideBodyTypes?: Record<string, React.Component>;
     overrideEventTypes?: Record<string, React.Component>;
+
+    // helper function to access relations for this event
+    getRelationsForEvent?: (eventId: string, relationType: string, eventType: string) => Relations;
 }
 
 @replaceableComponent("views.messages.MessageEvent")
@@ -154,6 +158,7 @@ export default class MessageEvent extends React.Component<IProps> implements IMe
             onMessageAllowed={this.onTileUpdate}
             permalinkCreator={this.props.permalinkCreator}
             mediaEventHelper={this.mediaHelper}
+            getRelationsForEvent={this.props.getRelationsForEvent}
         /> : null;
     }
 }

src/components/views/rooms/EventTile.tsx

@@ -990,7 +990,7 @@ export default class EventTile extends React.Component<IProps, IState> {
         return this.props.getRelationsForEvent(eventId, "m.annotation", "m.reaction");
     };
 
-    private onReactionsCreated = (relationType, eventType) => {
+    private onReactionsCreated = (relationType: string, eventType: string) => {
         if (relationType !== "m.annotation" || eventType !== "m.reaction") {
             return;
         }
@@ -1286,6 +1286,7 @@ export default class EventTile extends React.Component<IProps, IState> {
                             onHeightChanged={this.props.onHeightChanged}
                             tileShape={this.props.tileShape}
                             editState={this.props.editState}
+                            getRelationsForEvent={this.props.getRelationsForEvent}
                         />
                     </div>,
                 ]);
@@ -1324,6 +1325,7 @@ export default class EventTile extends React.Component<IProps, IState> {
                             tileShape={this.props.tileShape}
                             editState={this.props.editState}
                             replacingEventId={this.props.replacingEventId}
+                            getRelationsForEvent={this.props.getRelationsForEvent}
                         />
                         { actionBar }
                         { timestamp }
@@ -1373,6 +1375,7 @@ export default class EventTile extends React.Component<IProps, IState> {
                                 onHeightChanged={this.props.onHeightChanged}
                                 callEventGrouper={this.props.callEventGrouper}
                                 tileShape={this.props.tileShape}
+                                getRelationsForEvent={this.props.getRelationsForEvent}
                             />
                             { keyRequestInfo }
                             { this.renderThreadPanelSummary() }
@@ -1410,6 +1413,7 @@ export default class EventTile extends React.Component<IProps, IState> {
                             tileShape={this.props.tileShape}
                             onHeightChanged={this.props.onHeightChanged}
                             editState={this.props.editState}
+                            getRelationsForEvent={this.props.getRelationsForEvent}
                         />
                     </div>,
                     <a
@@ -1463,6 +1467,7 @@ export default class EventTile extends React.Component<IProps, IState> {
                                 permalinkCreator={this.props.permalinkCreator}
                                 onHeightChanged={this.props.onHeightChanged}
                                 callEventGrouper={this.props.callEventGrouper}
+                                getRelationsForEvent={this.props.getRelationsForEvent}
                             />
                             { keyRequestInfo }
                             { actionBar }

src/i18n/strings/en_EN.json

@@ -2045,8 +2045,10 @@
     "Declining …": "Declining …",
     "%(name)s wants to verify": "%(name)s wants to verify",
     "You sent a verification request": "You sent a verification request",
-    "%(number)s votes": "%(number)s votes",
-    "Based on %(total)s votes": "Based on %(total)s votes",
+    "%(count)s votes|other": "%(count)s votes",
+    "%(count)s votes|one": "%(count)s vote",
+    "Based on %(count)s votes|other": "Based on %(count)s votes",
+    "Based on %(count)s votes|one": "Based on %(count)s vote",
     "Error decrypting video": "Error decrypting video",
     "Error processing voice message": "Error processing voice message",
     "Add reaction": "Add reaction",

src/polls/consts.ts

@@ -18,6 +18,7 @@ import { UnstableValue } from "matrix-js-sdk/src/NamespacedValue";
 import { IContent } from "matrix-js-sdk/src/models/event";
 
 export const POLL_START_EVENT_TYPE = new UnstableValue("m.poll.start", "org.matrix.msc3381.poll.start");
+export const POLL_RESPONSE_EVENT_TYPE = new UnstableValue("m.poll.response", "org.matrix.msc3381.poll.response");
 export const POLL_KIND_DISCLOSED = new UnstableValue("m.poll.disclosed", "org.matrix.msc3381.poll.disclosed");
 export const POLL_KIND_UNDISCLOSED = new UnstableValue("m.poll.undisclosed", "org.matrix.msc3381.poll.undisclosed");
 
@@ -40,6 +41,12 @@ export interface IPollContent extends IContent {
     [TEXT_NODE_TYPE]: string;
 }
 
+export interface IPollResponse extends IContent {
+    [POLL_RESPONSE_EVENT_TYPE.name]: {
+        answers: string[];
+    };
+}
+
 export function makePollContent(question: string, answers: string[], kind: string): IPollContent {
     question = question.trim();
     answers = answers.map(a => a.trim()).filter(a => !!a);

test/components/views/messages/MPollBody-test.tsx

@@ -0,0 +1,476 @@
+/*
+Copyright 2021 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 React from "react";
+import { mount, ReactWrapper } from "enzyme";
+
+import sdk from "../../../skinned-sdk";
+import * as TestUtils from "../../../test-utils";
+
+import { Callback, IContent, MatrixEvent } from "matrix-js-sdk";
+import { ISendEventResponse } from "matrix-js-sdk/src/@types/requests";
+import { Relations } from "matrix-js-sdk/src/models/relations";
+import { IPollAnswer, IPollContent } from "../../../../src/polls/consts";
+import { UserVote, allVotes } from "../../../../src/components/views/messages/MPollBody";
+import { MatrixClientPeg } from "../../../../src/MatrixClientPeg";
+
+const _MPollBody = sdk.getComponent("views.messages.MPollBody");
+const MPollBody = TestUtils.wrapInMatrixClientContext(_MPollBody);
+
+MatrixClientPeg.matrixClient = {
+    getUserId: () => "@me:example.com",
+    sendEvent: () => Promise.resolve({ "event_id": "fake_send_id" }),
+};
+
+describe("MPollBody", () => {
+    it("finds no votes if there are none", () => {
+        expect(allVotes(newPollRelations([]))).toEqual([]);
+    });
+
+    it("can find all the valid responses to a poll", () => {
+        const ev1 = responseEvent();
+        const ev2 = responseEvent();
+        const badEvent = badResponseEvent();
+
+        const pollRelations = newPollRelations([ev1, badEvent, ev2]);
+        expect(allVotes(pollRelations)).toEqual([
+            new UserVote(
+                ev1.getTs(),
+                ev1.getSender(),
+                ev1.getContent()["org.matrix.msc3381.poll.response"].answers,
+            ),
+            new UserVote(
+                ev2.getTs(),
+                ev2.getSender(),
+                ev2.getContent()["org.matrix.msc3381.poll.response"].answers,
+            ),
+        ]);
+    });
+
+    it("finds no votes if none were made", () => {
+        const votes = [];
+        const body = newMPollBody(votes);
+        expect(votesCount(body, "pizza")).toBe("0 votes");
+        expect(votesCount(body, "poutine")).toBe("0 votes");
+        expect(votesCount(body, "italian")).toBe("0 votes");
+        expect(votesCount(body, "wings")).toBe("0 votes");
+        expect(body.find(".mx_MPollBody_totalVotes").text()).toBe("Based on 0 votes");
+    });
+
+    it("finds votes from multiple people", () => {
+        const votes = [
+            responseEvent("@andyb:example.com", "pizza"),
+            responseEvent("@bellc:example.com", "pizza"),
+            responseEvent("@catrd:example.com", "poutine"),
+            responseEvent("@dune2:example.com", "wings"),
+        ];
+        const body = newMPollBody(votes);
+        expect(votesCount(body, "pizza")).toBe("2 votes");
+        expect(votesCount(body, "poutine")).toBe("1 vote");
+        expect(votesCount(body, "italian")).toBe("0 votes");
+        expect(votesCount(body, "wings")).toBe("1 vote");
+        expect(body.find(".mx_MPollBody_totalVotes").text()).toBe("Based on 4 votes");
+    });
+
+    it("takes someone's most recent vote if they voted several times", () => {
+        const votes = [
+            responseEvent("@fiona:example.com", "pizza", 12),
+            responseEvent("@fiona:example.com", "wings", 20),   // latest fiona
+            responseEvent("@qbert:example.com", "pizza", 14),
+            responseEvent("@qbert:example.com", "poutine", 16), // latest qbert
+            responseEvent("@qbert:example.com", "wings", 15),
+        ];
+        const body = newMPollBody(votes);
+        expect(votesCount(body, "pizza")).toBe("0 votes");
+        expect(votesCount(body, "poutine")).toBe("1 vote");
+        expect(votesCount(body, "italian")).toBe("0 votes");
+        expect(votesCount(body, "wings")).toBe("1 vote");
+        expect(body.find(".mx_MPollBody_totalVotes").text()).toBe("Based on 2 votes");
+    });
+
+    it("uses my local vote", () => {
+        // Given I haven't voted
+        const votes = [
+            responseEvent("@nf:example.com", "pizza", 15),
+            responseEvent("@fg:example.com", "pizza", 15),
+            responseEvent("@hi:example.com", "pizza", 15),
+        ];
+        const body = newMPollBody(votes);
+
+        // When I vote for Italian
+        clickRadio(body, "italian");
+
+        // My vote is counted
+        expect(votesCount(body, "pizza")).toBe("3 votes");
+        expect(votesCount(body, "poutine")).toBe("0 votes");
+        expect(votesCount(body, "italian")).toBe("1 vote");
+        expect(votesCount(body, "wings")).toBe("0 votes");
+
+        expect(body.find(".mx_MPollBody_totalVotes").text()).toBe("Based on 4 votes");
+    });
+
+    it("overrides my other votes with my local vote", () => {
+        // Given two of us have voted for Italian
+        const votes = [
+            responseEvent("@me:example.com", "pizza", 12),
+            responseEvent("@me:example.com", "poutine", 13),
+            responseEvent("@me:example.com", "italian", 14),
+            responseEvent("@nf:example.com", "italian", 15),
+        ];
+        const body = newMPollBody(votes);
+
+        // When I click Wings
+        clickRadio(body, "wings");
+
+        // Then my vote is counted for Wings, and not for Italian
+        expect(votesCount(body, "pizza")).toBe("0 votes");
+        expect(votesCount(body, "poutine")).toBe("0 votes");
+        expect(votesCount(body, "italian")).toBe("1 vote");
+        expect(votesCount(body, "wings")).toBe("1 vote");
+
+        expect(body.find(".mx_MPollBody_totalVotes").text()).toBe("Based on 2 votes");
+    });
+
+    it("ignores extra answers", () => {
+        // When cb votes for 2 things, we consider the first only
+        const votes = [
+            responseEvent("@cb:example.com", ["pizza", "wings"]),
+            responseEvent("@da:example.com", "wings"),
+        ];
+        const body = newMPollBody(votes);
+        expect(votesCount(body, "pizza")).toBe("1 vote");
+        expect(votesCount(body, "poutine")).toBe("0 votes");
+        expect(votesCount(body, "italian")).toBe("0 votes");
+        expect(votesCount(body, "wings")).toBe("1 vote");
+        expect(body.find(".mx_MPollBody_totalVotes").text()).toBe("Based on 2 votes");
+    });
+
+    it("allows un-voting by passing an empty vote", () => {
+        const votes = [
+            responseEvent("@nc:example.com", "pizza", 12),
+            responseEvent("@nc:example.com", [], 13),
+            responseEvent("@md:example.com", "italian"),
+        ];
+        const body = newMPollBody(votes);
+        expect(votesCount(body, "pizza")).toBe("0 votes");
+        expect(votesCount(body, "poutine")).toBe("0 votes");
+        expect(votesCount(body, "italian")).toBe("1 vote");
+        expect(votesCount(body, "wings")).toBe("0 votes");
+        expect(body.find(".mx_MPollBody_totalVotes").text()).toBe("Based on 1 vote");
+    });
+
+    it("allows re-voting after un-voting", () => {
+        const votes = [
+            responseEvent("@op:example.com", "pizza", 12),
+            responseEvent("@op:example.com", [], 13),
+            responseEvent("@op:example.com", "italian", 14),
+            responseEvent("@qr:example.com", "italian"),
+        ];
+        const body = newMPollBody(votes);
+        expect(votesCount(body, "pizza")).toBe("0 votes");
+        expect(votesCount(body, "poutine")).toBe("0 votes");
+        expect(votesCount(body, "italian")).toBe("2 votes");
+        expect(votesCount(body, "wings")).toBe("0 votes");
+        expect(body.find(".mx_MPollBody_totalVotes").text()).toBe("Based on 2 votes");
+    });
+
+    it("treats any invalid answer as a spoiled ballot", () => {
+        // Note that tr's second vote has a valid first answer, but
+        // the ballot is still spoiled because the second answer is
+        // invalid, even though we would ignore it if we continued.
+        const votes = [
+            responseEvent("@tr:example.com", "pizza", 12),
+            responseEvent("@tr:example.com", ["pizza", "doesntexist"], 13),
+            responseEvent("@uy:example.com", "italian", 14),
+            responseEvent("@uy:example.com", "doesntexist", 15),
+        ];
+        const body = newMPollBody(votes);
+        expect(votesCount(body, "pizza")).toBe("0 votes");
+        expect(votesCount(body, "poutine")).toBe("0 votes");
+        expect(votesCount(body, "italian")).toBe("0 votes");
+        expect(votesCount(body, "wings")).toBe("0 votes");
+        expect(body.find(".mx_MPollBody_totalVotes").text()).toBe("Based on 0 votes");
+    });
+
+    it("allows re-voting after a spoiled ballot", () => {
+        const votes = [
+            responseEvent("@tr:example.com", "pizza", 12),
+            responseEvent("@tr:example.com", ["pizza", "doesntexist"], 13),
+            responseEvent("@uy:example.com", "italian", 14),
+            responseEvent("@uy:example.com", "doesntexist", 15),
+            responseEvent("@uy:example.com", "poutine", 16),
+        ];
+        const body = newMPollBody(votes);
+        expect(votesCount(body, "pizza")).toBe("0 votes");
+        expect(votesCount(body, "poutine")).toBe("1 vote");
+        expect(votesCount(body, "italian")).toBe("0 votes");
+        expect(votesCount(body, "wings")).toBe("0 votes");
+        expect(body.find(".mx_MPollBody_totalVotes").text()).toBe("Based on 1 vote");
+    });
+
+    it("renders nothing if poll has no answers", () => {
+        const answers = [];
+        const votes = [];
+        const body = newMPollBody(votes, answers);
+        expect(body.html()).toBe("");
+    });
+
+    it("renders nothing if poll has more than 20 answers", () => {
+        const answers = [...Array(21).keys()].map((i) => {
+            return { "id": `id${i}`, "org.matrix.msc1767.text": `Name ${i}` };
+        });
+        const votes = [];
+        const body = newMPollBody(votes, answers);
+        expect(body.html()).toBe("");
+    });
+
+    it("sends a vote event when I choose an option", () => {
+        const receivedEvents = [];
+        MatrixClientPeg.matrixClient.sendEvent = (
+            roomId: string,
+            eventType: string,
+            content: IContent,
+            txnId?: string,
+            callback?: Callback,
+        ): Promise<ISendEventResponse> => {
+            receivedEvents.push( { roomId, eventType, content, txnId, callback } );
+            return Promise.resolve({ "event_id": "fake_tracked_send_id" });
+        };
+
+        const votes = [];
+        const body = newMPollBody(votes);
+        clickRadio(body, "wings");
+        expect(receivedEvents).toEqual([
+            expectedResponseEvent("wings"),
+        ]);
+    });
+
+    it("sends only one vote event when I click several times", () => {
+        const receivedEvents = [];
+        MatrixClientPeg.matrixClient.sendEvent = (
+            roomId: string,
+            eventType: string,
+            content: IContent,
+            txnId?: string,
+            callback?: Callback,
+        ): Promise<ISendEventResponse> => {
+            receivedEvents.push( { roomId, eventType, content, txnId, callback } );
+            return Promise.resolve({ "event_id": "fake_tracked_send_id" });
+        };
+
+        const votes = [];
+        const body = newMPollBody(votes);
+        clickRadio(body, "wings");
+        clickRadio(body, "wings");
+        clickRadio(body, "wings");
+        clickRadio(body, "wings");
+        expect(receivedEvents).toEqual([
+            expectedResponseEvent("wings"),
+        ]);
+    });
+
+    it("sends several events when I click different options", () => {
+        const receivedEvents = [];
+        MatrixClientPeg.matrixClient.sendEvent = (
+            roomId: string,
+            eventType: string,
+            content: IContent,
+            txnId?: string,
+            callback?: Callback,
+        ): Promise<ISendEventResponse> => {
+            receivedEvents.push( { roomId, eventType, content, txnId, callback } );
+            return Promise.resolve({ "event_id": "fake_tracked_send_id" });
+        };
+
+        const votes = [];
+        const body = newMPollBody(votes);
+        clickRadio(body, "wings");
+        clickRadio(body, "italian");
+        clickRadio(body, "poutine");
+        expect(receivedEvents).toEqual([
+            expectedResponseEvent("wings"),
+            expectedResponseEvent("italian"),
+            expectedResponseEvent("poutine"),
+        ]);
+    });
+
+    it("renders a poll with no votes", () => {
+        const votes = [];
+        const body = newMPollBody(votes);
+        expect(body).toMatchSnapshot();
+    });
+
+    it("renders a poll with only non-local votes", () => {
+        const votes = [
+            responseEvent("@op:example.com", "pizza", 12),
+            responseEvent("@op:example.com", [], 13),
+            responseEvent("@op:example.com", "italian", 14),
+            responseEvent("@st:example.com", "wings", 15),
+            responseEvent("@qr:example.com", "italian", 16),
+        ];
+        const body = newMPollBody(votes);
+        expect(body).toMatchSnapshot();
+    });
+
+    it("renders a poll with local, non-local and invalid votes", () => {
+        const votes = [
+            responseEvent("@a:example.com", "pizza", 12),
+            responseEvent("@b:example.com", [], 13),
+            responseEvent("@c:example.com", "italian", 14),
+            responseEvent("@d:example.com", "italian", 14),
+            responseEvent("@e:example.com", "wings", 15),
+            responseEvent("@me:example.com", "italian", 16),
+        ];
+        const body = newMPollBody(votes);
+        clickRadio(body, "italian");
+        expect(body).toMatchSnapshot();
+    });
+});
+
+function newPollRelations(relationEvents: Array<MatrixEvent>): Relations {
+    const pollRelations = new Relations(
+        "m.reference", "org.matrix.msc3381.poll.response", null);
+    for (const ev of relationEvents) {
+        pollRelations.addEvent(ev);
+    }
+    return pollRelations;
+}
+
+function newMPollBody(
+    relationEvents: Array<MatrixEvent>,
+    answers?: IPollAnswer[],
+): ReactWrapper {
+    const pollRelations = new Relations(
+        "m.reference", "org.matrix.msc3381.poll.response", null);
+    for (const ev of relationEvents) {
+        pollRelations.addEvent(ev);
+    }
+
+    return mount(<MPollBody
+        mxEvent={new MatrixEvent({
+            "event_id": "$mypoll",
+            "room_id": "#myroom:example.com",
+            "content": newPollStart(answers),
+        })}
+        getRelationsForEvent={
+            (eventId: string, relationType: string, eventType: string) => {
+                expect(eventId).toBe("$mypoll");
+                expect(relationType).toBe("m.reference");
+                expect(eventType).toBe("org.matrix.msc3381.poll.response");
+                return pollRelations;
+            }
+        }
+    />);
+}
+
+function clickRadio(wrapper: ReactWrapper, value: string) {
+    wrapper.find(`StyledRadioButton[value="${value}"]`).simulate("click");
+}
+
+function votesCount(wrapper: ReactWrapper, value: string): string {
+    return wrapper.find(
+        `StyledRadioButton[value="${value}"] .mx_MPollBody_optionVoteCount`,
+    ).text();
+}
+
+function newPollStart(answers?: IPollAnswer[]): IPollContent {
+    if (!answers) {
+        answers = [
+            { "id": "pizza", "org.matrix.msc1767.text": "Pizza" },
+            { "id": "poutine", "org.matrix.msc1767.text": "Poutine" },
+            { "id": "italian", "org.matrix.msc1767.text": "Italian" },
+            { "id": "wings", "org.matrix.msc1767.text": "Wings" },
+        ];
+    }
+
+    return {
+        "org.matrix.msc3381.poll.start": {
+            "question": {
+                "org.matrix.msc1767.text": "What should we order for the party?",
+            },
+            "kind": "org.matrix.msc3381.poll.disclosed",
+            "answers": answers,
+        },
+        "org.matrix.msc1767.text": "What should we order for the party?\n" +
+            "1. Pizza\n2. Poutine\n3. Italian\n4. Wings",
+    };
+}
+
+function badResponseEvent(): MatrixEvent {
+    return new MatrixEvent(
+        {
+            "event_id": nextId(),
+            "type": "org.matrix.msc3381.poll.response",
+            "content": {
+                "m.relates_to": {
+                    "rel_type": "m.reference",
+                    "event_id": "$mypoll",
+                },
+                // Does not actually contain a response
+            },
+        },
+    );
+}
+
+function responseEvent(
+    sender = "@alice:example.com",
+    answers: string | Array<string> = "italian",
+    ts = 0,
+): MatrixEvent {
+    const ans = typeof answers === "string" ? [answers] : answers;
+    return new MatrixEvent(
+        {
+            "event_id": nextId(),
+            "room_id": "#myroom:example.com",
+            "origin_server_ts": ts,
+            "type": "org.matrix.msc3381.poll.response",
+            "sender": sender,
+            "content": {
+                "m.relates_to": {
+                    "rel_type": "m.reference",
+                    "event_id": "$mypoll",
+                },
+                "org.matrix.msc3381.poll.response": {
+                    "answers": ans,
+                },
+            },
+        },
+    );
+}
+
+function expectedResponseEvent(answer: string) {
+    return {
+        "content": {
+            "org.matrix.msc3381.poll.response": {
+                "answers": [answer],
+            },
+            "m.relates_to": {
+                "event_id": "$mypoll",
+                "rel_type": "m.reference",
+            },
+        },
+        "eventType": "org.matrix.msc3381.poll.response",
+        "roomId": "#myroom:example.com",
+        "txnId": undefined,
+        "callback": undefined,
+    };
+}
+
+let EVENT_ID = 0;
+function nextId(): string {
+    EVENT_ID++;
+    return EVENT_ID.toString();
+}