diff --git a/packages/material-ui/src/Popper/Popper.test.js b/packages/material-ui/src/Popper/Popper.test.js
index 0dc8f518f7cffe..50c78b8a61e33a 100644
--- a/packages/material-ui/src/Popper/Popper.test.js
+++ b/packages/material-ui/src/Popper/Popper.test.js
@@ -52,7 +52,7 @@ describe('<Popper />', () => {
           </Popper>
         </ThemeProvider>,
       );
-      expect(renderSpy.callCount).to.equal(2); // 2 for strict mode
+      expect(renderSpy.callCount).to.equal(2); // strict mode renders twice
       expect(renderSpy.args[0][0]).to.equal('top');
     });