Fix tests

Author: TrySound

src/index.js

@@ -314,10 +314,8 @@ module.exports = postcss.plugin(
       options.mode !== 'local' &&
       options.mode !== 'pure'
     ) {
-      return result.error(
-        Error(
-          'options.mode must be either "global", "local" or "pure" (default "local")'
-        )
+      throw Error(
+        'options.mode must be either "global", "local" or "pure" (default "local")'
       )
     }
     var pureMode = options.mode === 'pure'

test.js

@@ -441,11 +441,11 @@ const run = (css, options) =>
 tests.forEach(testCase => {
   test(testCase.should, () => {
     if (testCase.error) {
-      expect(run(testCase.input, testCase.options)).rejects.toMatch(
+      return expect(run(testCase.input, testCase.options)).rejects.toMatch(
         RegExp(testCase.error)
       )
     } else {
-      expect(run(testCase.input, testCase.options)).resolves.toEqual(
+      return expect(run(testCase.input, testCase.options)).resolves.toEqual(
         testCase.expected
       )
     }