fune/browser/components/sessionstore/test/browser_docshell_uuid_consistency.js

// First test - open a tab and duplicate it, using session restore to restore the history into the new tab.
add_task(async function duplicateTab() {
  const TEST_URL = "data:text/html,foo";
  let tab = BrowserTestUtils.addTab(gBrowser, TEST_URL);
  await BrowserTestUtils.browserLoaded(tab.linkedBrowser);

  if (!Services.appinfo.sessionHistoryInParent) {
    await SpecialPowers.spawn(tab.linkedBrowser, [], function () {
      let docshell = content.window.docShell.QueryInterface(
        Ci.nsIWebNavigation
      );
      let shEntry = docshell.sessionHistory.legacySHistory.getEntryAtIndex(0);
      is(shEntry.docshellID.toString(), docshell.historyID.toString());
    });
  } else {
    let historyID = tab.linkedBrowser.browsingContext.historyID;
    let shEntry =
      tab.linkedBrowser.browsingContext.sessionHistory.getEntryAtIndex(0);
    is(shEntry.docshellID.toString(), historyID.toString());
  }

  let tab2 = gBrowser.duplicateTab(tab);
  await BrowserTestUtils.browserLoaded(tab2.linkedBrowser);

  if (!Services.appinfo.sessionHistoryInParent) {
    await SpecialPowers.spawn(tab2.linkedBrowser, [], function () {
      let docshell = content.window.docShell.QueryInterface(
        Ci.nsIWebNavigation
      );
      let shEntry = docshell.sessionHistory.legacySHistory.getEntryAtIndex(0);
      is(shEntry.docshellID.toString(), docshell.historyID.toString());
    });
  } else {
    let historyID = tab2.linkedBrowser.browsingContext.historyID;
    let shEntry =
      tab2.linkedBrowser.browsingContext.sessionHistory.getEntryAtIndex(0);
    is(shEntry.docshellID.toString(), historyID.toString());
  }

  BrowserTestUtils.removeTab(tab);
  BrowserTestUtils.removeTab(tab2);
});

// Second test - open a tab and navigate across processes, which triggers sessionrestore to persist history.
add_task(async function contentToChromeNavigate() {
  const TEST_URL = "data:text/html,foo";
  let tab = BrowserTestUtils.addTab(gBrowser, TEST_URL);
  await BrowserTestUtils.browserLoaded(tab.linkedBrowser);

  if (!Services.appinfo.sessionHistoryInParent) {
    await SpecialPowers.spawn(tab.linkedBrowser, [], function () {
      let docshell = content.window.docShell.QueryInterface(
        Ci.nsIWebNavigation
      );
      let sh = docshell.sessionHistory;
      is(sh.count, 1);
      is(
        sh.legacySHistory.getEntryAtIndex(0).docshellID.toString(),
        docshell.historyID.toString()
      );
    });
  } else {
    let historyID = tab.linkedBrowser.browsingContext.historyID;
    let sh = tab.linkedBrowser.browsingContext.sessionHistory;
    is(sh.count, 1);
    is(sh.getEntryAtIndex(0).docshellID.toString(), historyID.toString());
  }

  // Force the browser to navigate to the chrome process.
  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, "about:config");
  await BrowserTestUtils.browserLoaded(tab.linkedBrowser);

  // Check to be sure that we're in the chrome process.
  let docShell = tab.linkedBrowser.frameLoader.docShell;

  // 'cause we're in the chrome process, we can just directly poke at the shistory.
  if (!Services.appinfo.sessionHistoryInParent) {
    let sh = docShell.QueryInterface(Ci.nsIWebNavigation).sessionHistory;

    is(sh.count, 2);
    is(
      sh.legacySHistory.getEntryAtIndex(0).docshellID.toString(),
      docShell.historyID.toString()
    );
    is(
      sh.legacySHistory.getEntryAtIndex(1).docshellID.toString(),
      docShell.historyID.toString()
    );
  } else {
    let sh = docShell.browsingContext.sessionHistory;

    is(sh.count, 2);
    is(
      sh.getEntryAtIndex(0).docshellID.toString(),
      docShell.historyID.toString()
    );
    is(
      sh.getEntryAtIndex(1).docshellID.toString(),
      docShell.historyID.toString()
    );
  }

  BrowserTestUtils.removeTab(tab);
});