diff --git a/__tests__/applyAtRule.test.js b/__tests__/applyAtRule.test.js
index 652b44940..1829a3f9d 100644
--- a/__tests__/applyAtRule.test.js
+++ b/__tests__/applyAtRule.test.js
@@ -1,14 +1,14 @@
 import postcss from 'postcss'
 import plugin from '../src/lib/substituteClassApplyAtRules'
 
-function run(input, opts) {
+function run(input, opts = () => {}) {
     return postcss([plugin(opts)]).process(input)
 }
 
 test("it copies a class's declarations into itself", () => {
     const output = '.a { color: red; } .b { color: red; }'
 
-    return run('.a { color: red; } .b { @apply .a; }', {}).then(result => {
+    return run('.a { color: red; } .b { @apply .a; }').then(result => {
         expect(result.css).toEqual(output)
         expect(result.warnings().length).toBe(0)
     })
@@ -38,16 +38,15 @@ test("it doesn't copy a media query definition into itself", () => {
 
         .b {
             @apply .a;
-        }`,
-        {}
-    ).then(result => {
+        }`)
+    .then(result => {
         expect(result.css).toEqual(output)
         expect(result.warnings().length).toBe(0)
     })
 })
 
 test('it fails if the class does not exist', () => {
-    run('.b { @apply .a; }', {}).catch(error => {
+    run('.b { @apply .a; }').catch(error => {
         expect(error.reason).toEqual('No .a class found.')
     })
 })
diff --git a/__tests__/focusableAtRule.test.js b/__tests__/focusableAtRule.test.js
index 51cdda213..04fb8ba64 100644
--- a/__tests__/focusableAtRule.test.js
+++ b/__tests__/focusableAtRule.test.js
@@ -1,7 +1,7 @@
 import postcss from 'postcss'
 import plugin from '../src/lib/substituteFocusableAtRules'
 
-function run(input, opts = {}) {
+function run(input, opts = () => {}) {
   return postcss([plugin(opts)]).process(input)
 }
 
@@ -18,7 +18,7 @@ test("it adds a focusable variant to each nested class definition", () => {
       .chocolate, .focus\\:chocolate:focus { color: brown; }
   `
 
-  return run(input, {}).then(result => {
+  return run(input).then(result => {
     expect(result.css).toEqual(output)
     expect(result.warnings().length).toBe(0)
   })
diff --git a/__tests__/hoverableAtRule.test.js b/__tests__/hoverableAtRule.test.js
index cd6747bd8..afcd5096f 100644
--- a/__tests__/hoverableAtRule.test.js
+++ b/__tests__/hoverableAtRule.test.js
@@ -1,7 +1,7 @@
 import postcss from 'postcss'
 import plugin from '../src/lib/substituteHoverableAtRules'
 
-function run(input, opts = {}) {
+function run(input, opts = () => {}) {
   return postcss([plugin(opts)]).process(input)
 }
 
@@ -18,7 +18,7 @@ test("it adds a hoverable variant to each nested class definition", () => {
       .chocolate, .hover\\:chocolate:hover { color: brown; }
   `
 
-  return run(input, {}).then(result => {
+  return run(input).then(result => {
     expect(result.css).toEqual(output)
     expect(result.warnings().length).toBe(0)
   })