fix: show every password error in its own line below the field (closes #493)

The add wallet screen reported a missing, short or mismatched password in
the flash line at the top of the popup, and the private key export,
recovery phrase and delete wallet screens each wrote to a line of their own
above the password field. All four now use showError() and hideError() with
a fixed-height error line below the field, as the send confirmation and
approval screens do. The line clears when the screen is shown again and
when the password is tried again. Other add wallet messages stay in the
flash line.

Model: opus-5-5

tests/passwordErrorLines.test.js

@@ -0,0 +1,159 @@
+// Every screen that asks for a password shows a password error the same way:
+// through showError() and hideError() in src/popup/views/helpers.js, in a
+// fixed-height error line below the password field, and never in the flash
+// line at the top of the popup
+// (https://git.eeqj.de/sneak/AutistMask/issues/493). These boot the real popup
+// over src/popup/index.html, so each error line has to exist in the markup,
+// and check that the error appears in it and clears again.
+
+jest.mock("../src/shared/vault", () => ({
+    decryptWithPassword: jest.fn(),
+    encryptWithPassword: jest.fn(),
+}));
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+} = require("./support/popupBoot");
+
+const PASSWORD = "correct horse battery staple";
+const WRONG_PASSWORD = "That password is incorrect. Please try again.";
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// The error line as the user sees it.
+function errorLine(page, id) {
+    return {
+        inMarkup: page.document.authoredIds.has(id),
+        text: page.text(id),
+        visibility: page.node(id).style.visibility,
+    };
+}
+
+function shown(text) {
+    return { inMarkup: true, text, visibility: "visible" };
+}
+
+const cleared = { inMarkup: true, text: "", visibility: "hidden" };
+
+describe("the add wallet screen", () => {
+    const ERROR = "add-wallet-password-error";
+
+    // First run: Welcome, "Add wallet", then the die for a valid phrase.
+    async function openAddWallet() {
+        const page = await bootPopup(undefined);
+        await page.click("btn-welcome-add");
+        await page.click("btn-generate-phrase");
+        return page;
+    }
+
+    function setPasswords(page, password, confirm) {
+        page.node("add-wallet-password").value = password;
+        page.node("add-wallet-password-confirm").value = confirm;
+    }
+
+    test("shows a password problem below the password fields, and clears it on the next press", async () => {
+        const page = await openAddWallet();
+        setPasswords(page, "short", "short");
+        await page.click("btn-add-wallet-confirm");
+        expect(errorLine(page, ERROR)).toEqual(
+            shown("Password must be at least 12 characters."),
+        );
+        expect(page.text("flash-msg")).toBe("");
+
+        // The password is fixed and the phrase emptied: the password error
+        // goes, and the phrase problem is still reported in the flash line.
+        setPasswords(page, PASSWORD, PASSWORD);
+        page.node("wallet-mnemonic").value = "";
+        await page.click("btn-add-wallet-confirm");
+        expect(errorLine(page, ERROR)).toEqual(cleared);
+        expect(page.text("flash-msg")).toBe(
+            "Enter a recovery phrase, or press the die.",
+        );
+
+        // Leaving clears the flash line and stops its timer, which would
+        // otherwise fire after this page is gone.
+        await page.click("btn-add-wallet-back");
+    });
+
+    test("clears the error when the screen is shown again", async () => {
+        const page = await openAddWallet();
+        setPasswords(page, PASSWORD, PASSWORD + " typo");
+        await page.click("btn-add-wallet-confirm");
+        expect(errorLine(page, ERROR)).toEqual(
+            shown("Passwords do not match."),
+        );
+
+        await page.click("btn-add-wallet-back");
+        await page.click("btn-welcome-add");
+        expect(errorLine(page, ERROR)).toEqual(cleared);
+    });
+});
+
+describe.each([
+    {
+        screen: "the private key export screen",
+        open: () => require("../src/popup/views/exportPrivkey").show(0, 0),
+        field: "export-privkey-password",
+        button: "btn-export-privkey-confirm",
+        error: "export-privkey-password-error",
+    },
+    {
+        screen: "the recovery phrase screen",
+        open: () => require("../src/popup/views/showPhrase").show(0),
+        field: "show-phrase-password",
+        button: "btn-show-phrase-reveal",
+        error: "show-phrase-password-error",
+    },
+    {
+        screen: "the delete wallet screen",
+        open: () => require("../src/popup/views/deleteWallet").show(0),
+        field: "delete-wallet-password",
+        button: "btn-delete-wallet-confirm",
+        error: "delete-wallet-password-error",
+    },
+])("$screen", ({ open, field, button, error }) => {
+    // Opens the screen and enters a password the vault rejects.
+    async function failedAttempt() {
+        const page = await bootPopup(unversionedValidProfile());
+        open();
+        const { decryptWithPassword } = require("../src/shared/vault");
+        decryptWithPassword.mockRejectedValue(new Error("wrong password"));
+        page.node(field).value = "not the password";
+        await page.click(button);
+        return { page, decryptWithPassword };
+    }
+
+    test("shows a wrong password below the password field", async () => {
+        const { page } = await failedAttempt();
+        expect(errorLine(page, error)).toEqual(shown(WRONG_PASSWORD));
+    });
+
+    test("clears the error while the next password is checked", async () => {
+        const { page, decryptWithPassword } = await failedAttempt();
+        let rejectDecrypt;
+        decryptWithPassword.mockReturnValue(
+            new Promise((resolve, reject) => {
+                rejectDecrypt = reject;
+            }),
+        );
+
+        page.node(field).value = "another guess";
+        const pressed = page.click(button);
+        await page.settle();
+        expect(errorLine(page, error)).toEqual(cleared);
+
+        rejectDecrypt(new Error("wrong password"));
+        await pressed;
+        expect(errorLine(page, error)).toEqual(shown(WRONG_PASSWORD));
+    });
+
+    test("clears the error when the screen is shown again", async () => {
+        const { page } = await failedAttempt();
+        open();
+        expect(errorLine(page, error)).toEqual(cleared);
+    });
+});