diff --git a/accessible/tests/browser/windows/ia2/browser.toml b/accessible/tests/browser/windows/ia2/browser.toml
index 025e64c03ea2..b72c9162a4c4 100644
--- a/accessible/tests/browser/windows/ia2/browser.toml
+++ b/accessible/tests/browser/windows/ia2/browser.toml
@@ -24,3 +24,6 @@ prefs = [
 ["browser_scrolling.js"]
 
 ["browser_text.js"]
+
+["browser_textSelectionContainer.js"]
+skip-if = ["true"] # Bug 1857116
diff --git a/accessible/tests/browser/windows/ia2/browser_text.js b/accessible/tests/browser/windows/ia2/browser_text.js
index b280e93d31b9..e5257b645025 100644
--- a/accessible/tests/browser/windows/ia2/browser_text.js
+++ b/accessible/tests/browser/windows/ia2/browser_text.js
@@ -9,11 +9,11 @@
  */
 addAccessibleTask(`<p id="cluster">a🤦‍♂️c`, async function testChar() {
   await runPython(`
-      doc = getDocIa2()
-      global cluster
-      cluster = findIa2ByDomId(doc, "cluster")
-      cluster = cluster.QueryInterface(IAccessibleText)
-    `);
+    doc = getDocIa2()
+    global cluster
+    cluster = findIa2ByDomId(doc, "cluster")
+    cluster = cluster.QueryInterface(IAccessibleText)
+  `);
   SimpleTest.isDeeply(
     await runPython(`cluster.textAtOffset(0, IA2_TEXT_BOUNDARY_CHAR)`),
     [0, 1, "a"],
diff --git a/accessible/tests/browser/windows/ia2/browser_textSelectionContainer.js b/accessible/tests/browser/windows/ia2/browser_textSelectionContainer.js
new file mode 100644
index 000000000000..d73de13dab8e
--- /dev/null
+++ b/accessible/tests/browser/windows/ia2/browser_textSelectionContainer.js
@@ -0,0 +1,75 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/* import-globals-from ../../../mochitest/text.js */
+
+loadScripts({ name: "text.js", dir: MOCHITESTS_DIR });
+
+function checkSelection(root, ranges) {
+  const selRanges = root.selectionRanges;
+  is(selRanges.length, ranges.length, "Correct number of selection ranges");
+  for (let r = 0; r < ranges.length; ++r) {
+    const selRange = selRanges.queryElementAt(r, nsIAccessibleTextRange);
+    testTextRange(selRange, root.id, ...ranges[r]);
+  }
+}
+
+/**
+ * Test IAccessibleTextSelectionContainer::setSelections.
+ */
+addAccessibleTask(
+  `<p id="p">ab<a id="link" href="/">cd</a>ef</p>`,
+  async function testSetSelections(browser, docAcc) {
+    docAcc.QueryInterface(nsIAccessibleText);
+    await runPython(`
+      global doc, docSel, p, link
+      doc = getDocIa2()
+      docSel = doc.QueryInterface(IAccessibleTextSelectionContainer)
+      p = findIa2ByDomId(doc, "p").QueryInterface(IAccessibleText)
+      link = findIa2ByDomId(doc, "link").QueryInterface(IAccessibleText)
+    `);
+
+    info("Selecting ab, end at link 0");
+    const p = findAccessibleChildByID(docAcc, "p");
+    let selected = waitForEvent(EVENT_TEXT_SELECTION_CHANGED, p);
+    await runPython(`
+      docSel.setSelections(1, byref(IA2TextSelection(p, 0, link, 0, False)))
+    `);
+    await selected;
+    const link = findAccessibleChildByID(docAcc, "link");
+    checkSelection(docAcc, [[p, 0, link, 0]]);
+
+    info("Selecting bc");
+    selected = waitForEvent(EVENT_TEXT_SELECTION_CHANGED, p);
+    await runPython(`
+      docSel.setSelections(1, byref(IA2TextSelection(p, 1, link, 1, False)))
+    `);
+    await selected;
+    checkSelection(docAcc, [[p, 1, link, 1]]);
+
+    info("Selecting de");
+    selected = waitForEvent(EVENT_TEXT_SELECTION_CHANGED, p);
+    await runPython(`
+      docSel.setSelections(1, byref(IA2TextSelection(link, 1, p, 4, False)))
+    `);
+    await selected;
+    checkSelection(docAcc, [[link, 1, p, 4]]);
+
+    info("Selecting a, c");
+    selected = waitForEvent(EVENT_TEXT_SELECTION_CHANGED, link);
+    await runPython(`
+      docSel.setSelections(2, (IA2TextSelection * 2)(
+        IA2TextSelection(p, 0, p, 1, False),
+        IA2TextSelection(link, 0, link, 1, False)
+      ))
+    `);
+    await selected;
+    checkSelection(docAcc, [
+      [p, 0, p, 1],
+      [link, 0, link, 1],
+    ]);
+  }
+);