feat(spec): add doubleTaps random-target builtin to defaultActions

pkg/spec/src/actions.ts

@@ -71,7 +71,7 @@ export function Wait(parameters: { durationMillis: number }): WaitAction {
 }
 
 function builtinGenerator(
-  name: "taps" | "typing" | "swipes" | "waitOnce" | "pressKeys",
+  name: "taps" | "doubleTaps" | "typing" | "swipes" | "waitOnce" | "pressKeys",
 ): ActionGenerator {
   return new Proxy({} as ActionGenerator, {
     get(_target, property) {
@@ -85,6 +85,7 @@ function builtinGenerator(
 }
 
 export const taps: ActionGenerator = builtinGenerator("taps");
+export const doubleTaps: ActionGenerator = builtinGenerator("doubleTaps");
 export const typing: ActionGenerator = builtinGenerator("typing");
 export const swipes: ActionGenerator = builtinGenerator("swipes");
 export const waitOnce: ActionGenerator = builtinGenerator("waitOnce");

pkg/spec/src/defaults/actions.ts

@@ -1,15 +1,21 @@
-import { swipes, taps, typing, weighted } from "../actions.ts";
+import { doubleTaps, swipes, taps, typing, weighted } from "../actions.ts";
 import type { ActionGenerator } from "../types.ts";
 
-export { pressKey, swipes, taps, typing, waitOnce } from "../actions.ts";
+export { doubleTaps, pressKey, swipes, taps, typing, waitOnce } from "../actions.ts";
 
 // A broad exploration generator: tap things, type edge-case values into fields,
 // and swipe. Layer it under targeted depth flows so the fuzzer wanders the whole
 // app while still driving the paths an author wrote. It deliberately omits the
 // hardware back key: backing out past the app's root screen exits the app under
 // test, and exploration must stay within the app.
+//
+// doubleTaps fires the same target twice ~50ms apart inside one step. Real users
+// double-tap (image zoom, like-to-favorite, play/pause); without this the fuzzer
+// can never produce sub-100ms event spacing, so race-window bugs (debounce gaps,
+// in-flight guards, init races) stay unreachable.
 export const defaultActions: ActionGenerator = weighted(
-  [55, taps],
+  [45, taps],
-  [30, typing],
+  [15, doubleTaps],
+  [25, typing],
   [15, swipes],
 );

pkg/spec/src/index.ts

@@ -38,6 +38,7 @@ export {
   Tap,
   Wait,
   actions,
+  doubleTaps,
   from,
   pressKey,
   swipes,

pkg/spec/src/types.ts

@@ -209,6 +209,7 @@ export interface SanderlingRuntime {
   pressKey: (parameters: { key: Key }) => PressKeyAction;
   wait: (parameters: { durationMillis: number }) => WaitAction;
   taps: ActionGenerator;
+  doubleTaps: ActionGenerator;
   typing: ActionGenerator;
   swipes: ActionGenerator;
   waitOnce: ActionGenerator;

pkg/spec/src/web-runtime.ts

@@ -350,6 +350,7 @@ const runtime = {
     return { kind: "Wait", durationMillis: p.durationMillis };
   },
   taps: { __sanderlingActionGenerator: true, __sanderlingKind: "taps" } as ActionGeneratorHandle,
+  doubleTaps: { __sanderlingActionGenerator: true, __sanderlingKind: "doubleTaps" } as ActionGeneratorHandle,
   typing: { __sanderlingActionGenerator: true, __sanderlingKind: "typing" } as ActionGeneratorHandle,
   swipes: { __sanderlingActionGenerator: true, __sanderlingKind: "swipes" } as ActionGeneratorHandle,
   waitOnce: { __sanderlingActionGenerator: true, __sanderlingKind: "waitOnce" } as ActionGeneratorHandle,
@@ -444,7 +445,9 @@ function resolveGenerator(handle: ActionGeneratorHandle): unknown {
       return resolveGenerator(inner);
     }
     case "taps":
-      return randomTap();
+      return randomTap("Tap");
+    case "doubleTaps":
+      return randomTap("DoubleTap");
     case "typing":
       return randomInput();
     case "swipes":
@@ -462,7 +465,7 @@ function resolveGenerator(handle: ActionGeneratorHandle): unknown {
 // doesn't re-walk the DOM and re-flush layout on every iteration.
 let randomTapCandidates: HTMLElement[] | null = null;
 
-function randomTap(): unknown {
+function randomTap(kind: "Tap" | "DoubleTap"): unknown {
   if (!randomTapCandidates) {
     randomTapCandidates = Array.from(
       document.querySelectorAll<HTMLElement>(
@@ -480,7 +483,7 @@ function randomTap(): unknown {
   if (!picked) return null;
   const rect = picked.getBoundingClientRect();
   return {
-    kind: "Tap",
+    kind,
     on: {
       x: Math.round(rect.left + rect.width / 2),
       y: Math.round(rect.top + rect.height / 2),

pkg/spec/test/api.test.ts

@@ -150,6 +150,7 @@ function installFakeRuntime(): RecordedRuntime {
     pressKey: ({ key }) => ({ kind: "PressKey", key }),
     wait: ({ durationMillis }) => ({ kind: "Wait", durationMillis }),
     taps: { __sanderlingActionGenerator: true, generate: () => [] },
+    doubleTaps: { __sanderlingActionGenerator: true, generate: () => [] },
     typing: { __sanderlingActionGenerator: true, generate: () => [] },
     swipes: { __sanderlingActionGenerator: true, generate: () => [] },
     waitOnce: { __sanderlingActionGenerator: true, generate: () => [] },

pkg/spec/test/defaults.test.ts

@@ -64,6 +64,7 @@ function installRuntime(initialState: State): RecordedRuntime {
     pressKey: ({ key }) => ({ kind: "PressKey", key }),
     wait: ({ durationMillis }) => ({ kind: "Wait", durationMillis }),
     taps: { __sanderlingActionGenerator: true, generate: () => [] } as ActionGenerator,
+    doubleTaps: { __sanderlingActionGenerator: true, generate: () => [] } as ActionGenerator,
     typing: { __sanderlingActionGenerator: true, generate: () => [] } as ActionGenerator,
     swipes: { __sanderlingActionGenerator: true, generate: () => [] } as ActionGenerator,
     waitOnce: { __sanderlingActionGenerator: true, generate: () => [] } as ActionGenerator,