--- a/browser/base/content/test/fullscreen/browser.ini
+++ b/browser/base/content/test/fullscreen/browser.ini
@@ -9,16 +9,18 @@ support-files = fullscreen.html fullscre
 [browser_fullscreen_api_fission.js]
 https_first_disabled = true
 support-files = fullscreen.html FullscreenFrame.sys.mjs
 [browser_fullscreen_context_menu.js]
 [browser_fullscreen_cross_origin.js]
 support-files = fullscreen.html fullscreen_frame.html
 [browser_fullscreen_enterInUrlbar.js]
 skip-if = (os == 'mac') || (os == 'linux') # Bug 1648649
+[browser_fullscreen_from_minimize.js]
+skip-if = (os == 'linux') || (os == 'win') # Bug 1818795 and Bug 1818796
 [browser_fullscreen_newtab.js]
 [browser_fullscreen_permissions_prompt.js]
 [browser_fullscreen_warning.js]
 support-files = fullscreen.html
 [browser_fullscreen_window_focus.js]
 skip-if = (os == 'mac') && debug # Bug 1568570
 [browser_fullscreen_window_open.js]
 skip-if = (os == 'linux') && swgl # Bug 1795491

new file mode 100644
--- /dev/null
+++ b/browser/base/content/test/fullscreen/browser_fullscreen_from_minimize.js
@@ -0,0 +1,72 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test checks whether fullscreen windows can transition to minimized windows,
+// and back again. This is sometimes not directly supported by the OS widgets. For
+// example, in macOS, the minimize button is greyed-out in the title bar of
+// fullscreen windows, making this transition impossible for users to initiate.
+// Still, web APIs do allow arbitrary combinations of window calls, and this test
+// exercises some of those combinations.
+
+add_task(async function() {
+  registerCleanupFunction(function() {
+    window.restore();
+  });
+
+  // We reuse these variables to create new promises for each transition.
+  let promiseSizeModeChange;
+  let promiseFullscreen;
+
+  ok(!window.fullScreen, "Window should be normal at start of test.");
+
+  // Get to fullscreen.
+  info("Requesting fullscreen.");
+  promiseFullscreen = document.documentElement.requestFullscreen();
+  await promiseFullscreen;
+  ok(window.fullScreen, "Window should be fullscreen before being minimized.");
+
+  // Transition between fullscreen and minimize states.
+  info("Requesting minimize on a fullscreen window.");
+  promiseSizeModeChange = BrowserTestUtils.waitForEvent(
+    window,
+    "sizemodechange"
+  );
+  window.minimize();
+  await promiseSizeModeChange;
+  is(
+    window.windowState,
+    window.STATE_MINIMIZED,
+    "Window should be minimized after fullscreen."
+  );
+
+  // Whether or not the previous transition worked, restore the window
+  // and then minimize it.
+  if (window.windowState != window.STATE_NORMAL) {
+    info("Restoring window.");
+    promiseSizeModeChange = BrowserTestUtils.waitForEvent(
+      window,
+      "sizemodechange"
+    );
+    window.restore();
+    await promiseSizeModeChange;
+    is(window.windowState, window.STATE_NORMAL, "Window should be normal.");
+  }
+
+  info("Requesting minimize on a normal window.");
+  promiseSizeModeChange = BrowserTestUtils.waitForEvent(
+    window,
+    "sizemodechange"
+  );
+  window.minimize();
+  await promiseSizeModeChange;
+  is(
+    window.windowState,
+    window.STATE_MINIMIZED,
+    "Window should be minimized before fullscreen."
+  );
+
+  info("Requesting fullscreen on a minimized window.");
+  promiseFullscreen = document.documentElement.requestFullscreen();
+  await promiseFullscreen;
+  ok(window.fullScreen, "Window should be fullscreen after being minimized.");
+});

--- a/browser/base/content/test/general/browser.ini
+++ b/browser/base/content/test/general/browser.ini
@@ -399,17 +399,17 @@ skip-if = true # Bug 1409184 disabled be
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_visibleTabs_bookmarkAllPages.js]
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_visibleTabs_tabPreview.js]
 skip-if =
   os == "win" && !debug
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_windowactivation.js]
-skip-if = 
+skip-if =
   verify
   os == "linux" && debug # Bug 1678774
 support-files =
   file_window_activation.html
   file_window_activation2.html
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_zbug569342.js]
 skip-if = true # Bug 1094240 - has findbar-related failures

new file mode 100644
--- /dev/null
+++ b/dom/base/test/fullscreen/file_fullscreen-single.html
@@ -0,0 +1,78 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+
+Open one window, focus it and enter fullscreen, then exit fullscreen.
+
+-->
+<head>
+  <title>Simple Fullscreen Enter and Exit Test</title>
+  <script src="/tests/SimpleTest/EventUtils.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="application/javascript" src="file_fullscreen-utils.js"></script>
+</head>
+<body>
+
+<div id="fullscreen-div"><p>Fullscreen div</p></div>
+
+<script type="application/javascript">
+
+function ok(condition, msg) {
+  opener.ok(condition, "[single] " + msg);
+}
+
+function is(value, expected, msg) {
+  opener.is(value, expected, "[single] " + msg);
+}
+
+function isnot(value, unexpected, msg) {
+  opener.isnot(value, unexpected, "[single] " + msg);
+}
+
+function info(msg) {
+  opener.info("[single] " + msg);
+}
+
+function windowResized() {
+  info(`Window resized to width: ${window.innerWidth}, height: ${window.innerHeight}.`);
+}
+
+async function begin() {
+  window.addEventListener('resize', windowResized);
+
+  info(`Starting window width: ${window.innerWidth}, height: ${window.innerHeight}.`);
+  let windowedWidth = window.innerWidth;
+  let windowedHeight = window.innerHeight;
+
+  info("Requesting fullscreen.");
+  let entryPromise = document.getElementById('fullscreen-div').requestFullscreen()
+  info("Fullscreen requested, waiting for promise to resolve.");
+
+  await entryPromise;
+
+  info("element.requestFullscreen() promise resolved.");
+  info(`Fullscreen window width: ${window.innerWidth}, height: ${window.innerHeight}.`);
+  isnot(document.fullscreenElement, null, "document.fullscreenElement should exist.");
+  ok(window.fullScreen, "window.fullScreen");
+  isnot(windowedWidth, window.innerWidth, "window width should be changed.");
+  isnot(windowedHeight, window.innerHeight, "window height should be changed.");
+
+  info("Requesting fullscreen exit.");
+  let exitPromise = document.exitFullscreen()
+  info("Fullscreen exit requested, waiting for promise to resolve.");
+
+  await exitPromise;
+
+  info("document.exitFullscreen() promise resolved.");
+  info(`Restored window width: ${window.innerWidth}, height: ${window.innerHeight}.`);
+  is(document.fullscreenElement, null, "document.fullscreenElement should be null.");
+  ok(!window.fullScreen, "window.fullScreen should be false.");
+  is(window.innerWidth, windowedWidth, "window width should be restored.");
+  is(window.innerHeight, windowedHeight, "window height should be restored.");
+  opener.nextTest();
+}
+
+</script>
+</pre>
+</body>
+</html>

--- a/dom/base/test/fullscreen/mochitest.ini
+++ b/dom/base/test/fullscreen/mochitest.ini
@@ -1,13 +1,13 @@
 [DEFAULT]
 tags = fullscreen
 support-files =
+  file_fullscreen-api-race.html
   file_fullscreen-api.html
-  file_fullscreen-api-race.html
   file_fullscreen-async.html
   file_fullscreen-backdrop.html
   file_fullscreen-denied-inner.html
   file_fullscreen-denied.html
   file_fullscreen-esc-exit-inner.html
   file_fullscreen-esc-exit.html
   file_fullscreen-event-order.html
   file_fullscreen-featurePolicy.html
@@ -22,26 +22,26 @@ support-files =
   file_fullscreen-navigation.html
   file_fullscreen-nested.html
   file_fullscreen-prefixed.html
   file_fullscreen-resize.html
   file_fullscreen-rollback.html
   file_fullscreen-scrollbar.html
   file_fullscreen-selector.html
   file_fullscreen-shadowdom.html
+  file_fullscreen-single.html
   file_fullscreen-sub-iframe.html
   file_fullscreen-svg-element.html
   file_fullscreen-table.html
   file_fullscreen-top-layer.html
   file_fullscreen-utils.js
   file_fullscreen-with-full-zoom.html
 
+[test_fullscreen-api-race.html]
+skip-if = toolkit == 'android' # same as test_fullscreen-api.html, 1356570
+  os == "mac" && debug
 [test_fullscreen-api.html]
 allow_xul_xbl = true  # XUL is used in file_fullscreen-api.html
 skip-if =
   toolkit == 'android'
   os == 'mac' && bits == 64 && debug # Bug 1579623
-[test_fullscreen-api-race.html]
-skip-if = toolkit == 'android' # same as test_fullscreen-api.html, 1356570
-  verify && debug && os == 'mac'
-  os == "mac" && debug
 [test_fullscreen_meta_viewport.html]
 [test_fullscreen_modal.html]

--- a/dom/base/test/fullscreen/test_fullscreen-api.html
+++ b/dom/base/test/fullscreen/test_fullscreen-api.html
@@ -23,16 +23,17 @@
 
 /** Tests for Bug 545812 **/
 SimpleTest.requestFlakyTimeout("untriaged");
 
 // Run the tests which go full-screen in new windows, as mochitests normally
 // run in an iframe, which by default will not have the allowfullscreen
 // attribute set, so full-screen won't work.
 var gTestWindows = [
+  { test: "file_fullscreen-single.html" },
   { test: "file_fullscreen-multiple.html",
     prefs: [["full-screen-api.exit-on.windowRaise", false],
             ["full-screen-api.exit-on.windowOpen", false]] },
   { test: "file_fullscreen-rollback.html" },
   { test: "file_fullscreen-esc-exit.html" },
   { test: "file_fullscreen-denied.html" },
   { test: "file_fullscreen-api.html" },
   { test: "file_fullscreen-hidden.html" },
@@ -67,16 +68,17 @@ function finish() {
 
 function nextTest() {
   if (testWindow) {
     info("Waiting for focus to return to main window");
     window.addEventListener("focus", function() {
       info("main window focused, starting next test");
       SimpleTest.executeSoon(runNextTest);
     }, {once: true});
+    info("testWindow.close()");
     testWindow.close();
   } else {
     SimpleTest.executeSoon(runNextTest);
   }
 }
 
 function waitForEvent(eventTarget, eventName, checkFn, callback) {
   eventTarget.addEventListener(eventName, function listener(event) {