Deprecate MSD class, fix tests

packages/core/src/common/classes.ts

@@ -200,6 +200,7 @@ export const MULTISTEP_DIALOG = `${NS}-multistep-dialog`;
 export const MULTISTEP_DIALOG_PANELS = `${MULTISTEP_DIALOG}-panels`;
 export const MULTISTEP_DIALOG_LEFT_PANEL = `${MULTISTEP_DIALOG}-left-panel`;
 export const MULTISTEP_DIALOG_RIGHT_PANEL = `${MULTISTEP_DIALOG}-right-panel`;
+/** @deprecated use `Classes.DIALOG_FOOTER` instead */
 export const MULTISTEP_DIALOG_FOOTER = `${MULTISTEP_DIALOG}-footer`;
 export const MULTISTEP_DIALOG_NAV_TOP = `${MULTISTEP_DIALOG}-nav-top`;
 export const MULTISTEP_DIALOG_NAV_RIGHT = `${MULTISTEP_DIALOG}-nav-right`;

packages/core/src/components/dialog/multistepDialog.tsx

@@ -217,7 +217,12 @@ export class MultistepDialog extends AbstractPureComponent2<MultistepDialogProps
         const maybeCloseButton = !isFooterCloseButtonVisible ? undefined : (
             <DialogStepButton text="Close" onClick={onClose} {...closeButtonProps} />
         );
-        return <DialogFooter actions={this.renderButtons()}>{maybeCloseButton}</DialogFooter>;
+        return (
+            // eslint-disable-next-line deprecation/deprecation -- need to keep adding this class for backcompat, can be removed in next major version
+            <DialogFooter className={Classes.MULTISTEP_DIALOG_FOOTER} actions={this.renderButtons()}>
+                {maybeCloseButton}
+            </DialogFooter>
+        );
     }
 
     private renderButtons() {

packages/core/test/multistep-dialog/multistepDialogTests.tsx

@@ -43,7 +43,7 @@ describe("<MultistepDialog>", () => {
             Classes.DIALOG_STEP_TITLE,
             Classes.DIALOG_FOOTER_ACTIONS,
         ].forEach(className => {
-            assert.lengthOf(dialog.find(`.${className}`), 1, `missing ${className}`);
+            assert.lengthOf(dialog.find(`.${className}`).hostNodes(), 1, `missing ${className}`);
         });
         dialog.unmount();
     });