feat(sample-app): ledger spec parity (#18)

* feat(sample-app): add FocusTracker

* feat(sample-app): support description on TextInput

* feat(sample-app): support description on AppButton and Segmented

* feat(sample-app): stable ids on login screen

* feat(sample-app): stable ids on add-account screen

* feat(sample-app): stable ids on add-transaction screen

* feat(sample-app): stable ids on home and ledger screens

* feat(sample-app): hoist error + form state into UiState

* feat(sample-app): register auth_status + accounts snapshots

* feat(sample-app): register ledger_rows + ledger_balance snapshots

* feat(sample-app): register error + focused_input snapshots

* refactor(sample-app): scaffold spec.ts extractors + safety

* feat(sample-app): spec accounting invariants

* feat(sample-app): spec state-machine monotonicity

* feat(sample-app): spec liveness properties

* feat(sample-app): spec auth + account action generators

* feat(sample-app): spec transaction action generators

* feat(sample-app): spec weighted workflow

* feat(sample-app): publish login form input snapshots

* feat(sample-app): publish account + txn input snapshots

* feat(sample-app): register form input snapshots

* fix(sample-app): sequence login + idempotent text inputs in spec

* fix(sample-app): clear UiState on page dispose

* fix(sample-app): tighten adversarial login, allow retype on error

* test(verifier): update sample-app spec integration for new selectors

* feat(sidecar): clear focused field before InputText types

* refactor(sample-app): simplify loginHelper to focus-driven sequencing

* refactor(sample-app): drop input-value UiState mirrors

* refactor(sample-app): drop input-value snapshot registrations

* test(verifier): adjust sample-app integration for replace-on-type

sidecar/src/main/kotlin/dev/uatu/sidecar/DriverBackend.kt

@@ -89,6 +89,31 @@ class StubDriverBackend(private val platform: String) : DriverBackend {
             return null
         }
 
+        // Hard cap on KEYCODE_DEL events per clear. Guards against a pathological
+        // hierarchy that reports an enormous text length for the focused field.
+        internal const val MAX_CLEAR_DELETES: Int = 1024
+
+        // Matches a uiautomator-dump <node ...> tag where `focused="true"` is
+        // present. Captures only the tag's attribute string so we can pull
+        // `text="..."` out of it without building a full XML tree.
+        private val FOCUSED_NODE = Regex(
+            "<node\\b([^>]*\\bfocused=\"true\"[^>]*)/?>",
+        )
+        private val TEXT_ATTRIBUTE = Regex("\\btext=\"([^\"]*)\"")
+
+        internal fun parseFocusedText(xml: String): String? {
+            val node = FOCUSED_NODE.find(xml) ?: return null
+            val match = TEXT_ATTRIBUTE.find(node.groupValues[1]) ?: return ""
+            return decodeXmlAttribute(match.groupValues[1])
+        }
+
+        private fun decodeXmlAttribute(value: String): String = value
+            .replace("&amp;", "&")
+            .replace("&lt;", "<")
+            .replace("&gt;", ">")
+            .replace("&quot;", "\"")
+            .replace("&apos;", "'")
+
         internal val KEY_MAP: Map<String, String> = mapOf(
             "back" to "KEYCODE_BACK",
             "home" to "KEYCODE_HOME",
@@ -158,9 +183,34 @@ class StubDriverBackend(private val platform: String) : DriverBackend {
 
     override fun inputText(text: String) {
         lastInputText = text
+        // `adb shell input text` types keystrokes at the caret, so repeated
+        // calls append. Clear the focused field first so the caller sees a
+        // pure replace: read the current value's length from the hierarchy,
+        // then move-end + N backspaces before typing.
+        clearFocusedField()
         runAdb(listOf("shell", "input", "text", text.replace(" ", "%s")))
     }
 
+    private fun clearFocusedField() {
+        val current = focusedFieldText() ?: return
+        if (current.isEmpty()) return
+        val deletes = minOf(current.length, MAX_CLEAR_DELETES)
+        val keyevents = mutableListOf("shell", "input", "keyevent", "KEYCODE_MOVE_END")
+        repeat(deletes) { keyevents.add("KEYCODE_DEL") }
+        runAdb(keyevents)
+    }
+
+    private fun focusedFieldText(): String? {
+        val xml = try {
+            hierarchy()
+        } catch (cause: Exception) {
+            println("inputText: hierarchy dump failed: $cause")
+            return null
+        }
+        if (xml.isBlank() || xml == "<hierarchy/>") return null
+        return parseFocusedText(xml)
+    }
+
     @Volatile var lastSwipe: SwipeRecord? = null
         private set
     @Volatile var lastKey: String? = null

sidecar/src/test/kotlin/dev/uatu/sidecar/InputTextClearTest.kt

@@ -0,0 +1,48 @@
+package dev.uatu.sidecar
+
+import org.junit.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
+
+class InputTextClearTest {
+
+    @Test fun parsesTextFromFocusedNode() {
+        val xml = """
+            <hierarchy>
+              <node text="ignored" focused="false"/>
+              <node resource-id="app:id/email" text="old@value" focused="true"/>
+            </hierarchy>
+        """.trimIndent()
+
+        assertEquals("old@value", StubDriverBackend.parseFocusedText(xml))
+    }
+
+    @Test fun returnsEmptyWhenFocusedNodeHasNoTextAttribute() {
+        val xml = """<hierarchy><node focused="true"/></hierarchy>"""
+
+        assertEquals("", StubDriverBackend.parseFocusedText(xml))
+    }
+
+    @Test fun returnsNullWhenNoFocusedNode() {
+        val xml = """<hierarchy><node text="x" focused="false"/></hierarchy>"""
+
+        assertNull(StubDriverBackend.parseFocusedText(xml))
+    }
+
+    @Test fun decodesXmlEntitiesInAttribute() {
+        val xml = """<hierarchy><node text="a&amp;b&lt;c&quot;d" focused="true"/></hierarchy>"""
+
+        assertEquals("a&b<c\"d", StubDriverBackend.parseFocusedText(xml))
+    }
+
+    @Test fun picksFirstFocusedNodeWhenMultiplePresent() {
+        val xml = """
+            <hierarchy>
+              <node text="first" focused="true"/>
+              <node text="second" focused="true"/>
+            </hierarchy>
+        """.trimIndent()
+
+        assertEquals("first", StubDriverBackend.parseFocusedText(xml))
+    }
+}