Add tests for coverage

Author: nmn

packages/@stylexjs/stylex/__tests__/stylex-test.js

@@ -22,6 +22,7 @@ describe('stylex', () => {
       'keyframes',
       'positionTry',
       'viewTransitionClass',
+      'defaultMarker',
     ].forEach((api) => {
       test(`stylex.${api}`, () => {
         expect(() => stylex[api]()).toThrow();
@@ -47,6 +48,18 @@ describe('stylex', () => {
         expect(() => stylex.types[api]()).toThrow();
       });
     });
+
+    [
+      'ancestor',
+      'descendant',
+      'siblingBefore',
+      'siblingAfter',
+      'anySibling',
+    ].forEach((api) => {
+      test(`stylex.when${api}`, () => {
+        expect(() => stylex.when[api](':hover')).toThrow();
+      });
+    });
   });
 
   describe('props', () => {

packages/@stylexjs/stylex/src/stylex.js

@@ -135,6 +135,24 @@ export const defaultMarker = (): StaticStyles<> => {
   throw errorForFn('defaultMarker');
 };
 
+export const when = {
+  ancestor: (_pseudo?: string): string => {
+    throw errorForFn('when.ancestor');
+  },
+  descendant: (_pseudo?: string): string => {
+    throw errorForFn('when.descendant');
+  },
+  siblingBefore: (_pseudo?: string): string => {
+    throw errorForFn('when.siblingBefore');
+  },
+  siblingAfter: (_pseudo?: string): string => {
+    throw errorForFn('when.siblingAfter');
+  },
+  anySibling: (_pseudo?: string): string => {
+    throw errorForFn('when.anySibling');
+  },
+};
+
 export const types = {
   angle: <T: string | 0 = string | 0>(
     _v: ValueWithDefault<T>,
@@ -222,6 +240,7 @@ type IStyleX = {
   }>,
   viewTransitionClass: (viewTransitionClass: ViewTransitionClass) => string,
   types: typeof types,
+  when: typeof when,
   __customProperties?: { [string]: mixed },
   ...
 };
@@ -242,6 +261,7 @@ _legacyMerge.keyframes = keyframes;
 _legacyMerge.positionTry = positionTry;
 _legacyMerge.props = props;
 _legacyMerge.types = types;
+_legacyMerge.when = when;
 _legacyMerge.viewTransitionClass = viewTransitionClass;
 
 export const legacyMerge: IStyleX = _legacyMerge;