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diff --git a/devtools/client/inspector/grids/test/browser_grids_grid-outline-cannot-show-outline.js b/devtools/client/inspector/grids/test/browser_grids_grid-outline-cannot-show-outline.js
new file mode 100644
index 0000000000..a2f293c44d
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+++ b/devtools/client/inspector/grids/test/browser_grids_grid-outline-cannot-show-outline.js
@@ -0,0 +1,57 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Tests that grid outline does not show when cells are too small to be drawn and that
+// "Cannot show outline for this grid." message is displayed.
+
+const TEST_URI = `
+  <style type='text/css'>
+    #grid {
+      display: grid;
+      grid-template-columns: repeat(51, 20px);
+      grid-template-rows: repeat(51, 20px);
+    }
+  </style>
+  <div id="grid">
+    <div id="cellA">cell A</div>
+    <div id="cellB">cell B</div>
+  </div>
+`;
+
+add_task(async function () {
+  await addTab("data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI));
+
+  const { inspector, gridInspector } = await openLayoutView();
+  const { document: doc } = gridInspector;
+  const { highlighters, store } = inspector;
+
+  await selectNode("#grid", inspector);
+  const outline = doc.getElementById("grid-outline-container");
+  const gridList = doc.getElementById("grid-list");
+  const checkbox = gridList.children[0].querySelector("input");
+
+  info("Toggling ON the CSS grid highlighter from the layout panel.");
+  const onHighlighterShown = highlighters.once("grid-highlighter-shown");
+  const onGridOutlineRendered = waitForDOM(doc, ".grid-outline-text", 1);
+  const onCheckboxChange = waitUntilState(
+    store,
+    state => state.grids.length == 1 && state.grids[0].highlighted
+  );
+  checkbox.click();
+  await onHighlighterShown;
+  await onCheckboxChange;
+  const elements = await onGridOutlineRendered;
+
+  const cannotShowGridOutline = elements[0];
+
+  info(
+    "Checking the grid outline is not rendered and an appropriate message is shown."
+  );
+  ok(!outline, "Outline component is not shown.");
+  ok(
+    cannotShowGridOutline,
+    "The message 'Cannot show outline for this grid' is displayed."
+  );
+});