1 files changed, 102 insertions, 0 deletions
diff --git a/docshell/test/navigation/browser_test_bfcache_eviction.js b/docshell/test/navigation/browser_test_bfcache_eviction.js
new file mode 100644
index 0000000000..32772fe42c
--- /dev/null
+++ b/docshell/test/navigation/browser_test_bfcache_eviction.js
@@ -0,0 +1,102 @@
+add_task(async function () {
+  // We don't want the number of total viewers to be calculated by the available size
+  // for this test case. Instead, fix the number of viewers.
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.sessionhistory.max_total_viewers", 3],
+      ["docshell.shistory.testing.bfevict", true],
+      // If Fission is disabled, the pref is no-op.
+      ["fission.bfcacheInParent", true],
+    ],
+  });
+
+  // 1. Open a tab
+  var testPage =
+    "data:text/html,<html id='html1'><body id='body1'>First tab ever opened</body></html>";
+  await BrowserTestUtils.withNewTab(
+    { gBrowser, url: testPage },
+    async function (browser) {
+      let testDone = {};
+      if (!SpecialPowers.Services.appinfo.sessionHistoryInParent) {
+        // 2.  Add a promise that will be resolved when the 'content viewer evicted' event goes off
+        testDone.promise = SpecialPowers.spawn(browser, [], async function () {
+          return new Promise(resolve => {
+            let webNavigation = content.docShell.QueryInterface(
+              Ci.nsIWebNavigation
+            );
+            let { legacySHistory } = webNavigation.sessionHistory;
+            // 3. Register a session history listener to listen for a 'content viewer evicted' event.
+            let historyListener = {
+              OnContentViewerEvicted() {
+                ok(
+                  true,
+                  "History listener got called after a content viewer was evicted"
+                );
+                legacySHistory.removeSHistoryListener(historyListener);
+                // 6. Resolve the promise when we got our 'content viewer evicted' event
+                resolve();
+              },
+              QueryInterface: ChromeUtils.generateQI([
+                "nsISHistoryListener",
+                "nsISupportsWeakReference",
+              ]),
+            };
+            legacySHistory.addSHistoryListener(historyListener);
+            // Keep the weak shistory listener alive
+            content._testListener = historyListener;
+          });
+        });
+      } else {
+        // 2.  Add a promise that will be resolved when the 'content viewer evicted' event goes off
+        testDone.promise = new Promise(resolve => {
+          testDone.resolve = resolve;
+        });
+        let shistory = browser.browsingContext.sessionHistory;
+        // 3. Register a session history listener to listen for a 'content viewer evicted' event.
+        let historyListener = {
+          OnContentViewerEvicted() {
+            ok(
+              true,
+              "History listener got called after a content viewer was evicted"
+            );
+            shistory.removeSHistoryListener(historyListener);
+            delete window._testListener;
+            // 6. Resolve the promise when we got our 'content viewer evicted' event
+            testDone.resolve();
+          },
+          QueryInterface: ChromeUtils.generateQI([
+            "nsISHistoryListener",
+            "nsISupportsWeakReference",
+          ]),
+        };
+        shistory.addSHistoryListener(historyListener);
+        // Keep the weak shistory listener alive
+        window._testListener = historyListener;
+      }
+
+      // 4. Open a second tab
+      testPage = `data:text/html,<html id='html1'><body id='body1'>I am a second tab!</body></html>`;
+      let tab2 = await BrowserTestUtils.openNewForegroundTab(
+        gBrowser,
+        testPage
+      );
+
+      // 5. Navigate the first tab to 4 different pages.
+      // We should get 1 content viewer evicted because it will be outside of the range.
+      // If we have the following pages in our session history: P1 P2 P3 P4 P5
+      // and we are currently at P5, then P1 is outside of the range
+      // (it is more than 3 entries away from current entry) and thus will be evicted.
+      for (var i = 0; i < 4; i++) {
+        testPage = `data:text/html,<html id='html1'><body id='body1'>${i}</body></html>`;
+        let pagePromise = BrowserTestUtils.browserLoaded(browser);
+        BrowserTestUtils.loadURIString(browser, testPage);
+        await pagePromise;
+      }
+      // 7. Wait for 'content viewer evicted' event to go off
+      await testDone.promise;
+
+      // 8. Close the second tab
+      BrowserTestUtils.removeTab(tab2);
+    }
+  );
+});