diff --git a/__tests__/customConfig.test.js b/__tests__/customConfig.test.js
index 24399bb43..f0c32aa93 100644
--- a/__tests__/customConfig.test.js
+++ b/__tests__/customConfig.test.js
@@ -29,3 +29,35 @@ test('it uses the values from the custom config file', () => {
       expect(result.css).toMatchCss(expected)
     })
 })
+
+test('custom config can be passed as an object', () => {
+  return postcss([tailwind({
+    screens: {
+      mobile: '400px',
+    },
+  })])
+    .process(
+      `
+        @responsive {
+          .foo {
+            color: blue;
+          }
+        }
+      `,
+      { from: undefined }
+    )
+    .then(result => {
+      const expected = `
+        .foo {
+          color: blue;
+        }
+        @media (min-width: 400px) {
+          .mobile\\:foo {
+            color: blue;
+          }
+        }
+      `
+
+      expect(result.css).toMatchCss(expected)
+    })
+})