Add more test for `ReactionsRowButton.tsx`

test/components/views/messages/ReactionsRowButton-test.tsx

@@ -116,4 +116,18 @@ describe("ReactionsRowButton", () => {
 
         expect(root.asFragment()).toMatchSnapshot();
     });
+
+    it("renders without a room", () => {
+        mockClient.getRoom.mockImplementation(() => null);
+
+        const props = createProps({});
+
+        const root = render(
+            <MatrixClientContext.Provider value={mockClient}>
+                <ReactionsRowButton {...props} />
+            </MatrixClientContext.Provider>,
+        );
+
+        expect(root.asFragment()).toMatchSnapshot();
+    });
 });

test/components/views/messages/__snapshots__/ReactionsRowButton-test.tsx.snap

@@ -97,3 +97,24 @@ exports[`ReactionsRowButton renders reaction row button emojis correctly 2`] = `
   </div>
 </DocumentFragment>
 `;
+
+exports[`ReactionsRowButton renders without a room 1`] = `
+<DocumentFragment>
+  <div
+    class="mx_AccessibleButton mx_ReactionsRowButton"
+    role="button"
+    tabindex="0"
+  >
+    <span
+      aria-hidden="true"
+      class="mx_ReactionsRowButton_content"
+    />
+    <span
+      aria-hidden="true"
+      class="mx_ReactionsRowButton_count"
+    >
+      2
+    </span>
+  </div>
+</DocumentFragment>
+`;