test: the test suite exits on its own, without --forceExit (closes #585)

Some tests left timers running when they ended, and --forceExit hid them; both test scripts drop it. Six background test files left the background's 20-second timer running while an approval was pending; each now stubs it for the whole file. Five popup test files left a flash message's two-second timer running; they now use fake timers, and a wait on real zero-delay timeouts became jest.advanceTimersByTimeAsync(0). Two ethers timers can still run for up to 250 ms after a test ends; they stop before jest checks for open handles.

Model: opus-5-5

Dockerfile

@@ -10,6 +10,7 @@ WORKDIR /app
 
 COPY script/ script/
 COPY package.json yarn.lock ./
+# yarn warns about the workspaces field in eslint and babel-plugin-istanbul; no newer release drops it.
 RUN script/bootstrap
 
 COPY . .

README.md

@@ -2053,15 +2053,21 @@ view would leave a wallet one click from deletion.
       fee estimate and the contract and never-sent recipient checks ask that
       network's RPC endpoint, and the Etherscan label check asks that network's
       explorer
-    - "Sign & Send" (correct password) when the gas limit, a fee per gas or the
+    - "Sign & Send" (correct password) when the gas limit or a fee is over its
-      total fee the RPC endpoint fills in at signing is over its bound in
+      bound → nothing is signed; "The gas limit or fee the RPC endpoint quoted
-      `assertWithinCeilings()` (`src/shared/approvalVerify.js`) → nothing is
+      for this transaction is more than this wallet will sign for, so it was not
-      signed; "The gas limit or fee the RPC endpoint quoted for this transaction
+      sent. Please go back and try again." in its own box, no screen change. For
-      is more than this wallet will sign for, so it was not sent. Please go back
+      an ETH amount that Send's "Max" filled in, the gas limit and fees are
-      and try again." in its own box, the same sentence for all three, no screen
+      those of this screen's own fee estimate (see Amount above). For any other
-      change
+      send, the RPC endpoint fills in the gas limit and fees at signing. Just
-    - "Sign & Send" (wrong password) → "Wrong password." on the password error
+      before signing, `assertWithinCeilings()` (`src/shared/approvalVerify.js`)
-      line, no screen change
+      refuses the send when any of these is over its bound:
+        - the gas limit
+        - each fee per gas the transaction sets
+        - the total fee: the gas limit times `maxFeePerGas`, or times `gasPrice`
+          when the transaction has no `maxFeePerGas`
+    - "Sign & Send" (wrong password) → "That password is incorrect. Please try
+      again." on the password error line, no screen change
     - "Sign & Send" signs as the From address above, not as whichever address is
       selected: the two are saved separately, so the popup can reopen onto this
       screen with another address selected. When the selected wallet does not
@@ -2233,6 +2239,8 @@ view would leave a wallet one click from deletion.
       **AddressDetail**
     - "Add" with a token already tracked, a scam-listed address, or a failed
       contract lookup → flash message, no screen change
+    - "Add", then the contract lookup answers while another screen shows, or
+      after AddToken was opened again → tracks the token, no screen change
     - "Add", then a network switch in Settings before the contract lookup
       answers → nothing is tracked; "The active network changed before the
       lookup finished, so the token was not added." flash message, no screen
@@ -2279,6 +2287,9 @@ view would leave a wallet one click from deletion.
           no user data and is made whether or not "Use Blockscout" is ticked.
     - If the network changes before either "Save" stores its URL, the URL is not
       saved and a flash message says so
+    - Either "Save" stores its URL only if the input still shows that URL when
+      the endpoint answers. Otherwise a flash message says that the URL was not
+      saved
     - Etherscan:
         - "Check recipients on Etherscan" checkbox, unticked until the user
           ticks it

package.json

@@ -6,8 +6,8 @@
     "license": "GPL-3.0",
     "private": true,
     "scripts": {
-        "test": "jest --forceExit --maxWorkers=3",
+        "test": "jest --maxWorkers=3",
-        "test:verbose": "jest --forceExit --maxWorkers=3 --verbose",
+        "test:verbose": "jest --maxWorkers=3 --verbose",
         "build": "node build.js",
         "lint": "eslint . && prettier --check .",
         "fmt": "prettier --write .",

script/bootstrap

@@ -118,6 +118,7 @@ ensure_yarn() {
     fi
 }
 
+# yarn warns about the workspaces field in eslint and babel-plugin-istanbul; no newer release drops it.
 install_js_deps() {
     if missing yarn && [ -s "$HOME/.nvm/nvm.sh" ]; then
         nvm_sh "nvm use $NODE_VERSION >/dev/null && cd \"$ROOT\" && \

src/popup/index.js

@@ -65,7 +65,14 @@ function renderWalletList() {
 const pageClosed = new AbortController();
 window.addEventListener("pagehide", () => pageClosed.abort());
 
+// While a refresh runs, a request through ctx is not dropped. The request sets
+// refreshAgain, and one more refresh runs once the running one ends. Several
+// requests in that time lead to one more refresh, not several. An import asks
+// for a refresh after its address scan. A refresh already running does not
+// have the addresses the scan found
+// (https://git.eeqj.de/sneak/AutistMask/issues/581).
 let refreshInFlight = false;
+let refreshAgain = false;
 
 // The ten-second refresh startRefresh() starts, stopped when the popup moves to
 // the recovery screen: there is no profile left to refresh.
@@ -89,7 +96,10 @@ let refreshTimer = null;
 // user turned "Use Blockscout" off. So the save drops every token the user has
 // not tracked if the stored setting is off by then.
 async function doRefreshAndRender() {
-    if (refreshInFlight) return;
+    if (refreshInFlight) {
+        refreshAgain = true;
+        return;
+    }
     refreshInFlight = true;
     try {
         await followStoredSettings();
@@ -132,28 +142,35 @@ async function doRefreshAndRender() {
         });
         renderWalletList();
     } catch (e) {
-        // Every call site fires this and walks away — the boot below, the ten
+        // No caller waits for this function, so it must never reject. An
-        // second interval, and eight views through ctx — so it must never
+        // unhandled rejection reports nothing. The save inside it reports its
-        // reject: an unhandled rejection is not a report of anything. The save
+        // own failure through onSaveFailure() (see src/shared/state.js); what
-        // inside it reports its own failure through onSaveFailure() (see
+        // is left here is a failed network round trip, which the next tick
-        // src/shared/state.js); what is left here is a failed network round
+        // retries.
-        // trip, which the next tick retries.
         log.errorf("popup: background refresh failed:", e);
     } finally {
         refreshInFlight = false;
     }
+    if (refreshAgain) {
+        refreshAgain = false;
+        doRefreshAndRender();
+    }
 }
 
 // Refreshes now and every ten seconds from then on. Called once a wallet
 // exists: by init() when the popup opens with one, and by AddWallet when it
 // adds one, which in a popup that opened on Welcome is the first
-// (https://git.eeqj.de/sneak/AutistMask/issues/530). With the refresh already
+// (https://git.eeqj.de/sneak/AutistMask/issues/530). With the ten-second
-// running it starts no second one, and on the recovery screen it does nothing.
+// refresh already started, it starts no second one. On the recovery screen it
+// does nothing.
 function startRefresh() {
     if (!$("view-state-recovery").classList.contains("hidden")) return;
     doRefreshAndRender();
     if (refreshTimer === null) {
-        refreshTimer = setInterval(doRefreshAndRender, 10000);
+        // A tick that finds a refresh running is dropped.
+        refreshTimer = setInterval(() => {
+            if (!refreshInFlight) return doRefreshAndRender();
+        }, 10000);
     }
 }
 

src/popup/views/addToken.js

@@ -5,7 +5,12 @@ const { lookupTokenInfo } = require("../../shared/balances");
 const { isScamAddress } = require("../../shared/scamlist");
 const { log } = require("../../shared/log");
 
+// Counts the times AddToken has opened. A contract lookup started before
+// AddToken was last opened changes neither the screen nor the status line.
+let addTokenScreenOpenings = 0;
+
 function show() {
+    addTokenScreenOpenings++;
     $("add-token-address").value = "";
     $("add-token-info").textContent = "";
     $("add-token-info").style.visibility = "hidden";
@@ -55,6 +60,7 @@ function init(ctx) {
         // The network the lookup asks, which Settings may switch away from
         // before it answers, as for a transaction in confirmTx.js.
         const chainId = currentNetwork().chainId;
+        const opening = addTokenScreenOpenings;
         try {
             const info = await lookupTokenInfo(
                 contractAddr,
@@ -80,6 +86,17 @@ function init(ctx) {
             });
             await saveState();
             ctx.doRefreshAndRender();
+            // If the lookup answers after AddToken was opened again, the
+            // token is still added, but the screen and the status line stay
+            // as they are.
+            if (addTokenScreenOpenings !== opening) return;
+            // The lookup is over, so a later Back onto AddToken shows no
+            // status.
+            infoEl.textContent = "";
+            infoEl.style.visibility = "hidden";
+            // If the lookup answers while another screen shows, the token is
+            // still added but the screen does not change.
+            if (state.currentView !== "add-token") return;
             // Pop the stack (back to address detail) and re-render it
             // so the newly added token is visible immediately.
             if (state.viewStack.length > 0) {
@@ -100,6 +117,7 @@ function init(ctx) {
                     ? detail
                     : "Could not add the token.",
             );
+            if (addTokenScreenOpenings !== opening) return;
             infoEl.textContent = "";
             infoEl.style.visibility = "hidden";
         }

src/popup/views/settings.js

@@ -339,17 +339,31 @@ function showNewSettings() {
 // Another page may have stored a different URL since then. So `url` is set in
 // the stored record too. "Saved." then means that the stored record holds
 // `url`.
-async function saveEndpoint(field, url, networkId) {
+//
+// `input` is the id of the input that the user typed `url` in. When another
+// page changes the network, "Use Blockscout" or "Check recipients on
+// Etherscan", this page draws Settings again. A redraw during the endpoint
+// check puts the URL from `state` back in the input. So if the input no longer
+// shows `url`, nothing is saved. The flash message then says that the URL was
+// changed during the check. The save compares the input and sets `url` in
+// `state` in one step. So a redraw after the comparison shows `url`.
+async function saveEndpoint(field, input, url, networkId) {
     let refused = false;
+    let inputChanged = false;
     await saveState((stored) => {
         refused =
             state.networkId !== networkId || stored.networkId !== networkId;
-        if (refused) return false;
+        inputChanged = $(input).value.trim() !== url;
+        if (refused || inputChanged) return false;
         state[field] = url;
         stored[field] = url;
     });
     if (refused) {
         showFlash("The URL was not saved because the network changed.");
+    } else if (inputChanged) {
+        showFlash(
+            "The URL was not saved because it was changed during the check.",
+        );
     } else {
         showFlash("Saved.");
     }
@@ -401,7 +415,7 @@ function init(_ctx) {
             showFlash("Could not reach endpoint.");
             return;
         }
-        await saveEndpoint("rpcUrl", url, net.id);
+        await saveEndpoint("rpcUrl", "settings-rpc", url, net.id);
     });
 
     $("btn-save-blockscout").addEventListener("click", async () => {
@@ -425,7 +439,7 @@ function init(_ctx) {
             showFlash("Could not reach endpoint.");
             return;
         }
-        await saveEndpoint("blockscoutUrl", url, net.id);
+        await saveEndpoint("blockscoutUrl", "settings-blockscout", url, net.id);
     });
 
     // Each change is made inside the save, holding the lock. So

src/popup/views/transactionDetail.js

@@ -311,10 +311,21 @@ function populateOnChainDetails(txData, chainId) {
     }
 }
 
+// Whether TransactionDetail still holds the transaction with `txHash` on
+// `chainId`. Opening another transaction replaces the one TransactionDetail
+// holds. A visit to Settings does not.
+function holdsTransaction(txHash, chainId) {
+    const tx = state.viewData.tx;
+    return tx?.hash === txHash && tx?.chainId === chainId;
+}
+
 // Reads the block, network details and calldata from Blockscout, and decodes
 // the calldata. While the stored "Use Blockscout" is off, Blockscout is not
 // asked. An answer that lands after the setting went off is dropped
 // (src/shared/storedSettings.js). Either way none of them is shown.
+//
+// Blockscout can answer after the user has opened another transaction. That
+// answer is dropped.
 async function loadFullTxDetails(txHash, chainId) {
     if (!(await storedSettingIsOn("useBlockscout"))) return;
     const section = $("tx-detail-calldata-section");
@@ -333,6 +344,7 @@ async function loadFullTxDetails(txHash, chainId) {
         if (!resp.ok) return;
         const txData = await resp.json();
         if (!(await storedSettingIsOn("useBlockscout"))) return;
+        if (!holdsTransaction(txHash, chainId)) return;
 
         // Populate on-chain detail fields (block, nonce, gas, fee)
         populateOnChainDetails(txData, chainId);

src/shared/chainSwitch.js

@@ -53,18 +53,31 @@ function clearPopupCaches() {
 // change. So the switch also resets these fields in the stored record:
 //
 // - every address's balance and token balances;
-// - the time of the last balance refresh.
+// - the time of the last balance refresh;
+// - the fraud contracts.
 //
-// A balance that the background or another page stored since this page's last
+// A balance or a fraud contract that the background or another page stored
-// save is then not kept under the new network
+// since this page's last save is then not kept under the new network
-// (https://git.eeqj.de/sneak/AutistMask/issues/653).
+// (https://git.eeqj.de/sneak/AutistMask/issues/653,
+// https://git.eeqj.de/sneak/AutistMask/issues/692).
+//
+// Before the switch, `state` takes the tracked tokens that another page stored
+// since this page's last save (takeStoredTrackedTokens() in state.js). The
+// switch then puts them away under the previous network, the network they were
+// added on. When the stored record is on another network, a switch saved
+// elsewhere has not reached this page yet. The stored record's tokens are then
+// that network's, and none are taken.
 async function onChainSwitch(newNetworkId) {
-    const { state, saveState } = require("./state");
+    const { state, saveState, takeStoredTrackedTokens } = require("./state");
     let net = null;
     await saveState((stored) => {
         if (state.networkId === newNetworkId) return false;
+        if (stored.networkId === state.networkId) {
+            takeStoredTrackedTokens(stored);
+        }
         net = applyChainSwitchFields(state, newNetworkId);
         stored.lastBalanceRefresh = 0;
+        stored.fraudContracts = [];
         for (const wallet of stored.wallets) {
             for (const addr of wallet.addresses) {
                 addr.balance = "0";

src/shared/state.js

@@ -125,11 +125,12 @@ function currentNetwork() {
     return networkById(state.networkId);
 }
 
-// The persisted fields as this page held them when its last loadState()
+// `baseline` holds the persisted fields as this page held them when its last
-// finished, or when its last successful saveState() began, with any network
+// loadState() finished, or when its last successful saveState() began.
-// switch saved elsewhere that this page has taken since (takeStoredNetwork()).
+// takeStoredNetwork() and takeStoredTrackedTokens() also write into it what
-// saveState() diffs the live state against this to find only the fields THIS
+// this page has taken from the stored record since then. saveState() diffs the
-// page changed since.
+// live state against `baseline` to find only the fields THIS page changed
+// since.
 //
 // Deep-cloned, not a reference: callers mutate persisted objects and arrays
 // in place (state.wallets.push(...)), and a reference baseline would mutate
@@ -442,8 +443,10 @@ function mergeNetworkEndpoints(base, ours, theirs) {
 // milder than the other two.
 //
 // Every other persisted field stays a whole-field diff:
-// `trackedTokens`/`fraudContracts`/`viewStack` are arrays of scalars with no
+// `fraudContracts`/`viewStack` are arrays of scalars with no per-element
-// per-element identity to merge by; `networkTrackedTokens` is diffed whole like
+// identity to merge by; a save diffs `trackedTokens` whole, and a switch in
+// Settings first merges that list by contract address
+// (takeStoredTrackedTokens()); `networkTrackedTokens` is diffed whole like
 // `trackedTokens` and `networkId`, the two fields a network switch moves
 // together with it; `tokenHolderCache` is a map shaped like the ones above,
 // but nothing in src/ ever writes an entry into it — it is only ever reset
@@ -615,6 +618,28 @@ function takeStoredNetwork(stored) {
     copyChainSwitchFields(baseline, structuredClone(stored));
 }
 
+// Give this page the tracked tokens of `stored`, a record on this page's
+// network that a save of this page has just read (onChainSwitch() in
+// src/shared/chainSwitch.js calls this from `beforeWrite`):
+//
+// - A token that another page tracked or removed since this page's last save
+//   is tracked or removed in `state` too.
+// - A token that this page tracked or removed since then stays as this page
+//   has it.
+//
+// `baseline` takes the stored list, so the save stores the list in `state`
+// whenever the two differ.
+function takeStoredTrackedTokens(stored) {
+    rawState.trackedTokens = mergeListByIdentity(
+        baseline.trackedTokens,
+        rawState.trackedTokens,
+        stored.trackedTokens,
+        (token) => token.address.toLowerCase(),
+        (base, ours) => ours,
+    );
+    baseline.trackedTokens = structuredClone(stored.trackedTokens);
+}
+
 // Rejects with StateUnusableError for a stored record this build cannot make
 // sense of. Nothing is assigned and `loaded` stays false in that case, so a
 // caller that ignores the rejection gets StateNotLoadedError on the first
@@ -661,6 +686,7 @@ module.exports = {
     saveState,
     onSaveFailure,
     takeStoredNetwork,
+    takeStoredTrackedTokens,
     loadState,
     currentAddress,
     currentNetwork,

tests/addTokenLateAnswer.test.js

@@ -0,0 +1,137 @@
+// A contract lookup on AddToken can answer after the user has left AddToken.
+// The token is still added, and the screen the user is on does not change
+// (https://git.eeqj.de/sneak/AutistMask/issues/603). An answer while AddToken
+// still shows goes to AddressDetail. Driven through the real popup over a
+// stored profile.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    TOKEN_ADDRESS,
+} = require("./support/popupBoot");
+
+const TOKEN = {
+    address: TOKEN_ADDRESS,
+    symbol: "TST",
+    decimals: 18,
+    name: "Test Token",
+};
+
+// A second contract address, typed after AddToken was opened again.
+const OTHER_TOKEN_ADDRESS = "0xBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB";
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// The popup reopened onto AddressDetail, then AddToken opened from it with
+// TOKEN's contract address typed in.
+async function openAddToken() {
+    const boot = await bootPopup(
+        unversionedValidProfile({
+            currentView: "address",
+            selectedWallet: 0,
+            selectedAddress: 0,
+        }),
+    );
+    expect(boot.pageErrors).toEqual([]);
+    await boot.click("btn-add-token");
+    expect(boot.visibleViews()).toEqual(["add-token"]);
+    boot.node("add-token-address").value = TOKEN.address;
+    return boot;
+}
+
+// Presses Add with a contract lookup that answers only when the function
+// returned here is called. That function waits for Add to finish.
+function addWithPendingLookup(boot) {
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    let answer;
+    lookupTokenInfo.mockImplementationOnce(
+        () =>
+            new Promise((resolve) => {
+                answer = resolve;
+            }),
+    );
+    const adding = boot.click("btn-add-token-confirm");
+    return async () => {
+        answer({
+            symbol: TOKEN.symbol,
+            decimals: TOKEN.decimals,
+            name: TOKEN.name,
+        });
+        await adding;
+    };
+}
+
+test("an answer after the user opened Settings adds the token and Settings stays", async () => {
+    const boot = await openAddToken();
+    const answerLookup = addWithPendingLookup(boot);
+    await boot.click("btn-settings");
+    expect(boot.visibleViews()).toEqual(["settings"]);
+
+    await answerLookup();
+    expect(boot.visibleViews()).toEqual(["settings"]);
+    expect(boot.storage.read("autistmask").trackedTokens).toEqual([TOKEN]);
+});
+
+test("Back from Settings onto AddToken after the lookup answered shows no lookup status", async () => {
+    const boot = await openAddToken();
+    const answerLookup = addWithPendingLookup(boot);
+    expect(boot.text("add-token-info")).toBe("Looking up token...");
+    await boot.click("btn-settings");
+    await answerLookup();
+
+    await boot.click("btn-settings-back");
+    expect(boot.visibleViews()).toEqual(["add-token"]);
+    expect(boot.text("add-token-info")).toBe("");
+    expect(boot.node("add-token-info").style.visibility).toBe("hidden");
+});
+
+test("an answer after AddToken was opened again adds the token and leaves AddToken and its status line as they are", async () => {
+    const boot = await openAddToken();
+    const answerFirstLookup = addWithPendingLookup(boot);
+    await boot.click("btn-add-token-back");
+    await boot.click("btn-add-token");
+    expect(boot.visibleViews()).toEqual(["add-token"]);
+    boot.node("add-token-address").value = OTHER_TOKEN_ADDRESS;
+    // The second lookup is never answered.
+    addWithPendingLookup(boot);
+
+    await answerFirstLookup();
+    expect(boot.visibleViews()).toEqual(["add-token"]);
+    expect(boot.text("add-token-info")).toBe("Looking up token...");
+    expect(boot.storage.read("autistmask").trackedTokens).toEqual([TOKEN]);
+});
+
+test("a lookup that fails after AddToken was opened again leaves the status line as it is", async () => {
+    const boot = await openAddToken();
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    let failFirstLookup;
+    lookupTokenInfo.mockImplementationOnce(
+        () =>
+            new Promise((_, reject) => {
+                failFirstLookup = reject;
+            }),
+    );
+    const firstAdd = boot.click("btn-add-token-confirm");
+    await boot.click("btn-add-token-back");
+    await boot.click("btn-add-token");
+    boot.node("add-token-address").value = OTHER_TOKEN_ADDRESS;
+    // The second lookup is never answered.
+    addWithPendingLookup(boot);
+
+    failFirstLookup(new Error("lookup failed"));
+    await firstAdd;
+    expect(boot.text("add-token-info")).toBe("Looking up token...");
+});
+
+test("an answer while AddToken still shows goes to AddressDetail with the token listed", async () => {
+    const boot = await openAddToken();
+    const answerLookup = addWithPendingLookup(boot);
+
+    await answerLookup();
+    expect(boot.visibleViews()).toEqual(["address"]);
+    expect(boot.node("address-balances").innerHTML).toContain("TST");
+    expect(boot.storage.read("autistmask").trackedTokens).toEqual([TOKEN]);
+});

tests/addressKey.test.js

@@ -161,7 +161,7 @@ function click(element) {
 
 // show() starts the fee estimate without awaiting it; this lets it settle.
 async function settle() {
-    for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
+    for (let i = 0; i < 10; i++) await jest.advanceTimersByTimeAsync(0);
 }
 
 // ------------------------------------------------------------ harness
@@ -188,7 +188,11 @@ let sent;
 // handler to the buttons it drew, as the browser's fresh list would have.
 let plusButton;
 
+// showFlash() starts a timer that clears the message one or two seconds later.
+// Each test here runs on fake timers and drops them in afterEach, so that timer
+// never outlives the test.
 beforeEach(() => {
+    jest.useFakeTimers();
     approvalDetails = null;
     sent = [];
     mockNode.broadcast = [];
@@ -239,6 +243,7 @@ beforeEach(() => {
 });
 
 afterEach(() => {
+    jest.useRealTimers();
     jest.restoreAllMocks();
 });
 

tests/backgroundApproval.test.js

@@ -537,7 +537,18 @@ async function settleIncludingRejections() {
     await new Promise((resolve) => setImmediate(resolve));
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
     jest.resetModules();
 });
@@ -1883,18 +1894,6 @@ describe("a closed approval window leaves the request pending", () => {
         return bg.actionPopups[bg.actionPopups.length - 1];
     }
 
-    // The timer that keeps the worker running while an approval is pending is
-    // stubbed, so no test here leaves that timer running when it ends.
-    let keepRunningTimer;
-    beforeEach(() => {
-        keepRunningTimer = jest
-            .spyOn(global, "setInterval")
-            .mockImplementation(() => 1);
-    });
-    afterEach(() => {
-        keepRunningTimer.mockRestore();
-    });
-
     test("the toolbar popup opens a closed transaction approval, and approving it there sends", async () => {
         const bg = loadBackground();
         const pending = bg.requestTx();

tests/backgroundStateIsolation.test.js

@@ -103,7 +103,18 @@ function deferred() {
     return { promise, resolve };
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
 });
 

tests/chainSwitchGate.test.js

@@ -56,7 +56,18 @@ async function settle() {
     for (let i = 0; i < 50; i++) await Promise.resolve();
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
 });
 

tests/coldWorkerChainSwitch.test.js

@@ -64,7 +64,18 @@ async function settle() {
     for (let i = 0; i < 50; i++) await Promise.resolve();
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
 });
 

tests/coldWorkerSendTransaction.test.js

@@ -76,7 +76,18 @@ async function settle() {
     for (let i = 0; i < 60; i++) await Promise.resolve();
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
 });
 

tests/connectedSitesWorkerRestart.test.js

@@ -57,7 +57,18 @@ async function settle() {
     for (let i = 0; i < 50; i++) await Promise.resolve();
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
     jest.resetModules();
 });

tests/deleteWalletLostPassword.test.js

@@ -102,6 +102,17 @@ function makeDocument() {
 
 // ------------------------------------------------------------ harness
 
+// showFlash() starts a timer that clears the message two seconds later. Each
+// test here runs on fake timers and drops them in afterEach, so that timer
+// never outlives the test.
+beforeEach(() => {
+    jest.useFakeTimers();
+});
+
+afterEach(() => {
+    jest.useRealTimers();
+});
+
 function wallet(name, secret, addresses) {
     return {
         type: "hd",

tests/refreshDuringRefresh.test.js

@@ -0,0 +1,157 @@
+// While a refresh runs, a request through ctx is not dropped. One more refresh
+// runs once the running one ends, however many were asked for in that time
+// (https://git.eeqj.de/sneak/AutistMask/issues/581). A tick of the ten-second
+// timer that finds a refresh running is dropped. Each test boots the real popup
+// over a stored profile and holds the ten-second refresh open. `readChain()`
+// sets each address's balance from `CHAIN`, as the real `refreshBalances()`
+// sets it from the node.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    ADDRESS,
+} = require("./support/popupBoot");
+const {
+    hdWalletFromMnemonic,
+    deriveAddressFromXpub,
+} = require("../src/shared/wallet");
+
+const PHRASE =
+    "abandon abandon abandon abandon abandon abandon " +
+    "abandon abandon abandon abandon abandon about";
+const PASSWORD = "correct horse battery staple";
+
+// The first two addresses of PHRASE, both used on the chain.
+const { xpub, firstAddress } = hdWalletFromMnemonic(PHRASE);
+const SECOND_ADDRESS = deriveAddressFromXpub(xpub, 1);
+
+// The ETH balance the chain holds for each address, in ether.
+const CHAIN = {
+    [ADDRESS]: "1.5",
+    [firstAddress]: "2.0",
+    [SECOND_ADDRESS]: "3.0",
+};
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// The balance stand-in for a refresh that returns.
+async function readChain(wallets) {
+    for (const wallet of wallets) {
+        for (const addr of wallet.addresses) {
+            addr.balance = CHAIN[addr.address];
+        }
+    }
+}
+
+// Boots the popup over a profile with one wallet. From then on,
+// `refreshBalances()` never returns unless the test answers it. So an unwanted
+// refresh is counted once and then waits, instead of starting more.
+async function boot() {
+    const page = await bootPopup(unversionedValidProfile());
+    expect(page.pageErrors).toEqual([]);
+    const { refreshBalances } = require("../src/shared/balances");
+    refreshBalances.mockImplementation(() => new Promise(() => {}));
+    return { page, refreshBalances };
+}
+
+// Starts the ten-second refresh and holds it open until finish() is called.
+// The held refresh then writes the chain's balances. finish() resolves once
+// the held refresh has saved them and drawn Home. The one refresh after the
+// held one also returns.
+async function holdRefresh(page) {
+    const { refreshBalances } = require("../src/shared/balances");
+    let answer;
+    refreshBalances
+        .mockImplementationOnce(async (wallets) => {
+            await new Promise((resolve) => {
+                answer = resolve;
+            });
+            await readChain(wallets);
+        })
+        .mockImplementationOnce(readChain);
+    const ticking = page.tick();
+    await page.settle();
+    return {
+        finish: async () => {
+            answer();
+            await ticking;
+        },
+    };
+}
+
+// Imports PHRASE on AddWallet. Its address scan finds the phrase's first two
+// addresses.
+async function importPhrase(page) {
+    const { scanForAddresses } = require("../src/shared/balances");
+    scanForAddresses.mockImplementationOnce(async () => ({
+        addresses: [
+            { address: firstAddress, index: 0 },
+            { address: SECOND_ADDRESS, index: 1 },
+        ],
+        nextIndex: 2,
+    }));
+    await page.click("btn-add-wallet-bottom");
+    await page.click("tab-mnemonic");
+    page.node("wallet-mnemonic").value = PHRASE;
+    page.node("add-wallet-password").value = PASSWORD;
+    page.node("add-wallet-password-confirm").value = PASSWORD;
+    await page.click("btn-add-wallet-confirm");
+}
+
+// Imports the private key `key` on AddWallet.
+async function importKey(page, key) {
+    await page.click("btn-add-wallet-bottom");
+    await page.click("tab-privkey");
+    page.node("import-private-key").value = key;
+    page.node("add-wallet-password").value = PASSWORD;
+    page.node("add-wallet-password-confirm").value = PASSWORD;
+    await page.click("btn-add-wallet-confirm");
+}
+
+test("addresses that an import finds during a refresh show their balances once one more refresh returns", async () => {
+    const { page } = await boot();
+    const refresh = await holdRefresh(page);
+
+    await importPhrase(page);
+    expect(page.visibleViews()).toEqual(["main"]);
+    expect(page.text("flash-msg")).toBe("Found 2 addresses.");
+
+    await refresh.finish();
+    await page.settle();
+
+    const list = page.node("wallet-list").innerHTML;
+    expect(list).toContain("<span>2.0000</span>");
+    expect(list).toContain("<span>3.0000</span>");
+});
+
+test("several requests during a refresh lead to exactly one more refresh", async () => {
+    const { page, refreshBalances } = await boot();
+    const refresh = await holdRefresh(page);
+    const calls = refreshBalances.mock.calls.length;
+
+    await importKey(page, "0x" + "11".repeat(32));
+    await importKey(page, "0x" + "22".repeat(32));
+    await importPhrase(page);
+    expect(refreshBalances).toHaveBeenCalledTimes(calls);
+
+    await refresh.finish();
+    await page.settle();
+
+    expect(refreshBalances).toHaveBeenCalledTimes(calls + 1);
+});
+
+test("a tick of the ten-second timer during a refresh starts no other refresh", async () => {
+    const { page, refreshBalances } = await boot();
+    const refresh = await holdRefresh(page);
+    const calls = refreshBalances.mock.calls.length;
+
+    await page.tick();
+
+    await refresh.finish();
+    await page.settle();
+
+    expect(refreshBalances).toHaveBeenCalledTimes(calls);
+});

tests/sendAmountRule.test.js

@@ -131,10 +131,14 @@ async function review(amount, token) {
 async function confirm(amount, token) {
     const txInfo = await review("0.5", token);
     confirmTx.show({ ...txInfo, amount });
-    for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
+    for (let i = 0; i < 10; i++) await jest.advanceTimersByTimeAsync(0);
 }
 
+// showFlash() starts a timer that clears the message two seconds later. Each
+// test here runs on fake timers and drops them in afterEach, so that timer
+// never outlives the test.
 beforeEach(() => {
+    jest.useFakeTimers();
     elements.clear();
     state.wallets = [
         {
@@ -167,6 +171,10 @@ beforeEach(() => {
     state.currentView = null;
 });
 
+afterEach(() => {
+    jest.useRealTimers();
+});
+
 describe.each([
     ["1e-3", "ETH"],
     ["1e-3", "TOK"],

tests/sendMax.test.js

@@ -277,14 +277,18 @@ async function review() {
 
 // show() starts the fee estimate without awaiting it; this lets it settle.
 async function settle() {
-    for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
+    for (let i = 0; i < 10; i++) await jest.advanceTimersByTimeAsync(0);
 }
 
 function canSend() {
     return !el("btn-confirm-send").disabled;
 }
 
+// showFlash() starts a timer that clears the message two seconds later. Each
+// test here runs on fake timers and drops them in afterEach, so that timer
+// never outlives the test.
 beforeEach(() => {
+    jest.useFakeTimers();
     elements.clear();
     log.errorf.mockClear();
     pageClosed = new AbortController();
@@ -297,6 +301,10 @@ beforeEach(() => {
     mockNode.broadcast = [];
 });
 
+afterEach(() => {
+    jest.useRealTimers();
+});
+
 describe("Max on an ETH send", () => {
     test("fills in the exact balance minus the fee reserve", async () => {
         await refreshWith(BALANCE_WEI);

tests/settingsEndpointSave.test.js

@@ -47,3 +47,123 @@ test.each([
         expect(page.text("flash-msg")).toBe("Saved.");
     },
 );
+
+// The user types a URL in Settings and taps "Save". While the check waits for
+// the endpoint's answer, another page turns "Use Blockscout" on. This page
+// follows that change and draws Settings again, with the stored URL in the
+// input. The check then passes. The typed URL is not stored. The flash message
+// says that the URL was changed during the check
+// (https://git.eeqj.de/sneak/AutistMask/issues/695).
+test.each([
+    { button: "btn-save-rpc", input: "settings-rpc", field: "rpcUrl" },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+    },
+])(
+    "$button stores nothing when Settings is drawn again during the check",
+    async ({ button, input, field }) => {
+        const page = await bootPopup(unversionedValidProfile());
+        await page.click("btn-settings");
+        const storedUrl = page.value(input);
+        let answer;
+        globalThis.fetch.mockReturnValue(
+            new Promise((resolve) => {
+                answer = resolve;
+            }),
+        );
+
+        page.node(input).value = "https://typed.example.invalid";
+        const saving = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        // The browser announces this write to this page.
+        await page.storage.local.set({
+            autistmask: {
+                ...page.storage.read("autistmask"),
+                useBlockscout: true,
+            },
+        });
+        await page.settle();
+        expect(page.node("settings-use-blockscout").checked).toBe(true);
+        // This answer passes both endpoint checks on Ethereum Mainnet.
+        answer({
+            ok: true,
+            json: async () => ({ result: NETWORKS.mainnet.chainId }),
+        });
+        await Promise.all(saving);
+        await page.settle();
+
+        expect(page.storage.read("autistmask")[field]).toBe(storedUrl);
+        expect(page.value(input)).toBe(storedUrl);
+        expect(page.text("flash-msg")).toBe(
+            "The URL was not saved because it was changed during the check.",
+        );
+    },
+);
+
+// As above, but another write holds the lock. So this page's follow of the
+// change to "Use Blockscout" waits for the lock. The endpoint answers while the
+// input still shows the typed URL. The save then asks for the lock, after the
+// follow did. So the follow draws Settings again before the save compares the
+// input.
+test.each([
+    { button: "btn-save-rpc", input: "settings-rpc", field: "rpcUrl" },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+    },
+])(
+    "$button stores nothing when Settings is drawn again while the save waits for the lock",
+    async ({ button, input, field }) => {
+        const page = await bootPopup(unversionedValidProfile());
+        await page.click("btn-settings");
+        const storedUrl = page.value(input);
+        let answer;
+        globalThis.fetch.mockReturnValue(
+            new Promise((resolve) => {
+                answer = resolve;
+            }),
+        );
+        const typedUrl = "https://typed.example.invalid";
+
+        page.node(input).value = typedUrl;
+        const saving = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        let releaseLock;
+        const lockHeld = navigator.locks.request(
+            "autistmask",
+            () =>
+                new Promise((resolve) => {
+                    releaseLock = resolve;
+                }),
+        );
+        // The browser announces this write to this page.
+        await page.storage.local.set({
+            autistmask: {
+                ...page.storage.read("autistmask"),
+                useBlockscout: true,
+            },
+        });
+        await page.settle();
+        // This answer passes both endpoint checks on Ethereum Mainnet.
+        answer({
+            ok: true,
+            json: async () => ({ result: NETWORKS.mainnet.chainId }),
+        });
+        await page.settle();
+        expect(page.value(input)).toBe(typedUrl);
+        releaseLock();
+        await lockHeld;
+        await Promise.all(saving);
+        await page.settle();
+
+        expect(page.node("settings-use-blockscout").checked).toBe(true);
+        expect(page.storage.read("autistmask")[field]).toBe(storedUrl);
+        expect(page.value(input)).toBe(storedUrl);
+        expect(page.text("flash-msg")).toBe(
+            "The URL was not saved because it was changed during the check.",
+        );
+    },
+);

tests/trackedTokensPerNetwork.test.js

@@ -5,6 +5,9 @@
 // a contract lookup that answers after one. Driven through the real popup over
 // a stored profile; the same switch made by the background is in
 // tests/coldWorkerChainSwitch.test.js.
+//
+// The tests of what another page stored before a switch in Settings cover a
+// fraud contract too (https://git.eeqj.de/sneak/AutistMask/issues/692).
 
 const {
     bootPopup,
@@ -178,9 +181,8 @@ test("a token added by contract address on Sepolia is tracked on Sepolia only",
 });
 
 // Another popup page tracks DAI on Ethereum Mainnet after this page's last
-// save. The switch's save writes only the token lists that this page changed.
+// save. The switch to Sepolia puts DAI away under Ethereum Mainnet.
-// So DAI stays in `trackedTokens`, the active network's list.
+test("a token another page tracked before a switch in Settings stays tracked on Ethereum Mainnet", async () => {
-test("a token another page tracked before a switch in Settings stays in trackedTokens", async () => {
     const boot = await bootPopup(unversionedValidProfile());
     expect(boot.pageErrors).toEqual([]);
     boot.storage.write("autistmask", {
@@ -193,10 +195,97 @@ test("a token another page tracked before a switch in Settings stays in trackedT
 
     const stored = boot.storage.read("autistmask");
     expect(stored.networkId).toBe("sepolia");
-    expect(stored.trackedTokens).toEqual([MAINNET_TOKEN]);
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([MAINNET_TOKEN]);
+});
+
+// Another popup page stops tracking DAI on Ethereum Mainnet after this page's
+// last save. This page still holds DAI. The switch to Sepolia does not store
+// DAI under Ethereum Mainnet again.
+test("a token another page removed before a switch in Settings stays removed", async () => {
+    const boot = await bootPopup(
+        unversionedValidProfile({ trackedTokens: [MAINNET_TOKEN] }),
+    );
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        trackedTokens: [],
+    });
+
+    await boot.click("btn-settings");
+    await chooseNetwork(boot, "sepolia");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
     expect(stored.networkTrackedTokens.mainnet).toEqual([]);
 });
 
+// Another popup page removes DAI after this page's last save. That page then
+// adds DAI again, typing the contract address in lower case. The two pages'
+// entries for DAI match, because contract addresses are compared ignoring
+// letter case. The switch to Sepolia keeps this page's entry under Ethereum
+// Mainnet.
+test("a token another page added again with a lower-case address keeps this page's entry", async () => {
+    const boot = await bootPopup(
+        unversionedValidProfile({ trackedTokens: [MAINNET_TOKEN] }),
+    );
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        trackedTokens: [
+            { ...MAINNET_TOKEN, address: MAINNET_TOKEN.address.toLowerCase() },
+        ],
+    });
+
+    await boot.click("btn-settings");
+    await chooseNetwork(boot, "sepolia");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.networkTrackedTokens.mainnet).toEqual([MAINNET_TOKEN]);
+});
+
+// Another popup page saves a switch to Sepolia after this page's last save.
+// TST is tracked on Sepolia. This page has not taken that switch yet. A switch
+// to Sepolia in this page's Settings keeps TST off Ethereum Mainnet's list.
+test("a token tracked on Sepolia when another page switched there is not tracked on Ethereum Mainnet", async () => {
+    const boot = await bootPopup(unversionedValidProfile());
+    expect(boot.pageErrors).toEqual([]);
+    await boot.click("btn-settings");
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkId: "sepolia",
+        trackedTokens: [SEPOLIA_TOKEN],
+    });
+
+    await chooseNetwork(boot, "sepolia");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([SEPOLIA_TOKEN]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([]);
+});
+
+// Another popup page records a fraud contract on Ethereum Mainnet after this
+// page's last save. The switch to Sepolia drops that fraud contract, as the
+// switch drops this page's own.
+test("a fraud contract another page recorded before a switch in Settings is not kept on Sepolia", async () => {
+    const boot = await bootPopup(unversionedValidProfile());
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        fraudContracts: [NEW_TOKEN_ADDRESS],
+    });
+
+    await boot.click("btn-settings");
+    await chooseNetwork(boot, "sepolia");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.fraudContracts).toEqual([]);
+});
+
 // The contract lookup on SettingsAddToken answers on Ethereum Mainnet while the
 // switch to Sepolia waits for the lock. The page adds the token to Ethereum
 // Mainnet's list. The switch then keeps that list for Ethereum Mainnet.

tests/transactionDetailLateAnswer.test.js

@@ -0,0 +1,202 @@
+// TransactionDetail shows only details that Blockscout gave for the
+// transaction on screen (https://git.eeqj.de/sneak/AutistMask/issues/675).
+//
+// The screen asks Blockscout for its transaction and does not wait for the
+// answer. So the user can press Back and open another transaction before
+// Blockscout answers for the first. The first answer must then fill nothing on
+// the second transaction's screen. An answer that lands while Settings is up
+// must still fill TransactionDetail.
+//
+// Driven through the real popup over a stored profile
+// (tests/support/popupBoot.js). Each transaction is opened as a history screen
+// opens it: the current screen is pushed, then transactionDetail.show() draws
+// the transaction.
+
+"use strict";
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    ADDRESS,
+} = require("./support/popupBoot");
+
+const MAINNET_BLOCKSCOUT = "https://eth.blockscout.com/api/v2";
+const SEPOLIA_BLOCKSCOUT = "https://eth-sepolia.blockscout.com/api/v2";
+const RECIPIENT = "0x2222222222222222222222222222222222222222";
+
+// A history entry for a send of 1 `symbol` from ADDRESS to RECIPIENT, on the
+// network with `chainId`.
+function historyEntry(hash, chainId, symbol) {
+    return {
+        hash,
+        from: ADDRESS,
+        to: RECIPIENT,
+        value: "1.0000",
+        exactValue: "1.0",
+        symbol,
+        timestamp: 1790000000,
+        isError: false,
+        direction: "sent",
+        directionLabel: "Sent",
+        contractAddress: null,
+        chainId,
+    };
+}
+
+const FIRST = historyEntry("0x" + "aa".repeat(32), "0x1", "ETH");
+const SECOND = historyEntry("0x" + "bb".repeat(32), "0x1", "ETH");
+// A transaction on Sepolia with the same hash as FIRST.
+const FIRST_ON_SEPOLIA = historyEntry(FIRST.hash, "0xaa36a7", "SepoliaETH");
+
+// The URL that asks Blockscout for `entry`, on the network it was sent on.
+function requestUrl(entry) {
+    const blockscout =
+        entry.chainId === "0x1" ? MAINNET_BLOCKSCOUT : SEPOLIA_BLOCKSCOUT;
+    return blockscout + "/transactions/" + entry.hash;
+}
+
+// What Blockscout reports for each transaction, by the URL that asks for it.
+const ANSWERS = {
+    [requestUrl(FIRST)]: {
+        block_number: 21000001,
+        nonce: 4441,
+        fee: { value: "21000000000000" },
+        raw_input: "0x11111111",
+        method: "firstMethod",
+    },
+    [requestUrl(SECOND)]: {
+        block_number: 21000002,
+        nonce: 4442,
+        fee: { value: "42000000000000" },
+        raw_input: "0x22222222",
+        method: "secondMethod",
+    },
+    [requestUrl(FIRST_ON_SEPOLIA)]: {
+        block_number: 21000003,
+        nonce: 4443,
+        fee: { value: "63000000000000" },
+        raw_input: "0x33333333",
+        method: "sepoliaMethod",
+    },
+};
+
+// The text each answer puts on screen: its block, nonce, fee, method name and
+// raw data. No text from one answer appears in another.
+const FIRST_SHOWN = [
+    "21000001",
+    "4441",
+    "0.000021 ETH",
+    "firstMethod",
+    "0x11111111",
+];
+const SECOND_SHOWN = [
+    "21000002",
+    "4442",
+    "0.000042 ETH",
+    "secondMethod",
+    "0x22222222",
+];
+const FIRST_ON_SEPOLIA_SHOWN = [
+    "21000003",
+    "4443",
+    "0.000063 SepoliaETH",
+    "sepoliaMethod",
+    "0x33333333",
+];
+
+// Everything drawn in the fields that Blockscout's answer fills.
+function drawnDetails(page) {
+    return [
+        "tx-detail-block",
+        "tx-detail-nonce",
+        "tx-detail-fee",
+        "tx-detail-calldata-action",
+        "tx-detail-rawdata",
+    ]
+        .map((id) => page.node(id).innerHTML + page.node(id).textContent)
+        .join("\n");
+}
+
+// Opens `entry` on TransactionDetail, as a history screen does.
+function open(entry) {
+    require("../src/popup/views/helpers").pushCurrentView();
+    require("../src/popup/views/transactionDetail").show(entry);
+}
+
+// The URLs of every request to Blockscout so far, in order.
+function requestedUrls() {
+    return globalThis.fetch.mock.calls.map(([url]) => url);
+}
+
+// Boots the popup on Home with "Use Blockscout" on. Blockscout answers every
+// request at once from ANSWERS, except the request for `held`. Returns the
+// page and answer(), which lets the answer for `held` land.
+async function bootWithHeldRequest(held) {
+    const page = await bootPopup(
+        unversionedValidProfile({ useBlockscout: true }),
+    );
+    let answer;
+    const heldAnswer = new Promise((resolve) => {
+        answer = resolve;
+    });
+    globalThis.fetch = jest.fn(async (url) => {
+        if (url === requestUrl(held)) await heldAnswer;
+        return { ok: true, status: 200, json: async () => ANSWERS[url] };
+    });
+    return { page, answer: () => answer() };
+}
+
+// The user opens `first`, whose request to Blockscout is held. Then the user
+// presses Back and opens `second`. Then the answer for `first` lands. Returns
+// the page.
+async function firstAnswerLandsOnSecond(first, second) {
+    const { page, answer } = await bootWithHeldRequest(first);
+    open(first);
+    await page.settle();
+    await page.click("btn-tx-back");
+    expect(page.visibleViews()).toEqual(["main"]);
+    open(second);
+    await page.settle();
+    expect(requestedUrls()).toEqual([requestUrl(first), requestUrl(second)]);
+    answer();
+    await page.settle();
+    expect(page.visibleViews()).toEqual(["transaction"]);
+    return page;
+}
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+test("an answer for the first transaction that lands on the second one's screen fills nothing", async () => {
+    const page = await firstAnswerLandsOnSecond(FIRST, SECOND);
+
+    const drawn = drawnDetails(page);
+    for (const text of SECOND_SHOWN) expect(drawn).toContain(text);
+    for (const text of FIRST_SHOWN) expect(drawn).not.toContain(text);
+});
+
+test("an answer for a hash on mainnet that lands on the same hash's screen on Sepolia fills nothing", async () => {
+    const page = await firstAnswerLandsOnSecond(FIRST, FIRST_ON_SEPOLIA);
+
+    const drawn = drawnDetails(page);
+    for (const text of FIRST_ON_SEPOLIA_SHOWN) expect(drawn).toContain(text);
+    for (const text of FIRST_SHOWN) expect(drawn).not.toContain(text);
+});
+
+test("an answer that lands while Settings is up still fills TransactionDetail", async () => {
+    const { page, answer } = await bootWithHeldRequest(FIRST);
+    open(FIRST);
+    await page.settle();
+    await page.click("btn-settings");
+    expect(page.visibleViews()).toEqual(["settings"]);
+    answer();
+    await page.settle();
+    await page.click("btn-settings");
+
+    expect(page.visibleViews()).toEqual(["transaction"]);
+    expect(requestedUrls()).toEqual([requestUrl(FIRST)]);
+    const drawn = drawnDetails(page);
+    for (const text of FIRST_SHOWN) expect(drawn).toContain(text);
+});

tests/walletDefects.test.js

@@ -357,6 +357,11 @@ describe("every way to a signature or the private key refuses a defective wallet
     });
 
     beforeEach(() => {
+        // showFlash() starts a timer that clears the message two seconds
+        // later. Each test here runs on fake timers and drops them in
+        // afterEach, so that timer never outlives the test.
+        jest.useFakeTimers();
+
         const broken = brokenXprvWallet();
         // A balance, so that no Send button's zero-balance refusal can stand
         // in for the defect check.
@@ -398,6 +403,7 @@ describe("every way to a signature or the private key refuses a defective wallet
     });
 
     afterEach(() => {
+        jest.useRealTimers();
         state.wallets = [];
         state.activeAddress = null;
         state.selectedWallet = null;