[test] Fix outdated tests

Author: eps1lon

packages/material-ui-styles/src/withStyles.js

@@ -85,9 +85,7 @@ const withStyles = (stylesOrCreator, options = {}) => Component => {
 
       return new Error(
         'Material-UI: The `innerRef` prop is deprecated and will be removed in v5. ' +
-          `Refs are now automatically forwarded to the inner component.${
-            process.env.NODE_ENV === 'test' ? Date.now() : ''
-          }`,
+          'Refs are now automatically forwarded to the inner component.',
       );
     }),
   };

packages/material-ui-styles/src/withStyles.test.js

@@ -80,6 +80,7 @@ describe('withStyles', () => {
 
       afterEach(() => {
         consoleErrorMock.reset();
+        PropTypes.resetWarningCache();
       });
 
       it('is deprecated', () => {

packages/material-ui-styles/src/withTheme.js

@@ -35,9 +35,7 @@ const withTheme = Component => {
 
       return new Error(
         'Material-UI: The `innerRef` prop is deprecated and will be removed in v5. ' +
-          `Refs are now automatically forwarded to the inner component.${
-            process.env.NODE_ENV === 'test' ? Date.now() : ''
-          }`,
+          'Refs are now automatically forwarded to the inner component.',
       );
     }),
   };

packages/material-ui-styles/src/withTheme.test.js

@@ -62,7 +62,7 @@ describe('withTheme', () => {
           return null;
         }
       }
-      const ThemedTarget = withTheme()(TargetComponent);
+      const ThemedTarget = withTheme(TargetComponent);
 
       const ref = React.createRef();
       mount(
@@ -75,7 +75,7 @@ describe('withTheme', () => {
     });
 
     it('forwards refs to React.forwardRef types', () => {
-      const ThemedTarget = withTheme()(
+      const ThemedTarget = withTheme(
         React.forwardRef((props, ref) => <div {...props} ref={ref} />),
       );
 
@@ -96,10 +96,11 @@ describe('withTheme', () => {
 
       afterEach(() => {
         consoleErrorMock.reset();
+        PropTypes.resetWarningCache();
       });
 
       it('is deprecated', () => {
-        const ThemedDiv = withTheme()('div');
+        const ThemedDiv = withTheme('div');
 
         mount(
           <>