1 files changed, 97 insertions, 0 deletions
diff --git a/docshell/test/mochitest/test_bug1747033.html b/docshell/test/mochitest/test_bug1747033.html
new file mode 100644
index 0000000000..539b78fec0
--- /dev/null
+++ b/docshell/test/mochitest/test_bug1747033.html
@@ -0,0 +1,97 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test history after loading multipart</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" href="/tests/SimpleTest/test.css"/>
+  <script>
+    SimpleTest.waitForExplicitFinish();
+
+    function runTest() {
+      let bc = new BroadcastChannel("bug1747033");
+      new Promise(resolve => {
+        bc.addEventListener("message", ({ data: { historyLength } }) => {
+          is(historyLength, 1, "Correct length for first normal load.");
+
+          resolve();
+        }, { once: true });
+
+        window.open("file_bug1747033.sjs", "", "noopener");
+      }).then(() => {
+        return new Promise(resolve => {
+          let loaded = 0;
+          bc.addEventListener("message", function listener({ data: { historyLength } }) {
+            ++loaded;
+
+            is(historyLength, 2, `Correct length for multipart load ${loaded}.`);
+
+            // We want 3 parts in total.
+            if (loaded < 3) {
+              if (loaded == 2) {
+                // We've had 2 parts, make the server send the last part.
+                fetch("file_bug1747033.sjs?sendLastPart");
+              } else {
+                fetch("file_bug1747033.sjs?sendNextPart");
+              }
+              return;
+            }
+
+            bc.removeEventListener("message", listener);
+            resolve();
+          });
+
+          bc.postMessage({ cmd: "load", arg: "file_bug1747033.sjs?multipart" });
+        });
+      }).then(() => {
+        return new Promise(resolve => {
+          bc.addEventListener("message", ({ data: { historyLength } }) => {
+            is(historyLength, 2, "Correct length after calling replaceState in multipart.");
+
+            resolve();
+          }, { once: true });
+
+          bc.postMessage({ cmd: "replaceState", arg: "file_bug1747033.sjs?replaced" });
+        });
+      }).then(() => {
+        return new Promise(resolve => {
+          bc.addEventListener("message", ({ data: { historyLength } }) => {
+            is(historyLength, 3, "Correct length for first normal load after multipart.");
+
+            resolve();
+          }, { once: true });
+
+          bc.postMessage({ cmd: "load", arg: "file_bug1747033.sjs" });
+        });
+      }).then(() => {
+        return new Promise(resolve => {
+          let goneBack = 0;
+          bc.addEventListener("message", function listener({ data: { historyLength } }) {
+            ++goneBack;
+
+            is(historyLength, 3, "Correct length after going back.");
+
+            if (goneBack == 1) {
+              bc.postMessage({ cmd: "back" });
+            } else if (goneBack == 2) {
+              bc.removeEventListener("message", listener);
+              resolve();
+            }
+          });
+
+          bc.postMessage({ cmd: "back" });
+        });
+      }).then(() => {
+        bc.postMessage({ cmd: "close" });
+
+        SimpleTest.finish();
+      });
+    }
+  </script>
+</head>
+<body onload="runTest();">
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+</body>
+</html>