fix(chargepilot): a percent sign the driver reads, not the one the formatter escapes

The battery calibration hint read "Charging to 100 %%", and the charge-model
notice "at least 2 %%", because both strings escaped their percent for a
format call that never happens: they are rendered by plain getString(id),
which hands back the two characters as written. A single % is the literal,
with formatted="false" so lint does not read it as a conversion.

StringPercentTest fails on any %% left in a string with no positional
argument, in both locales, so the next one is caught before it ships. Gradle
cannot see resources as an input of a JVM test, so the test task declared
res/ and the seeded fixtures itself — without that the guard stays
UP-TO-DATE and a changed string passes the check unread.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: malys

app/build.gradle.kts

@@ -115,6 +115,21 @@ tasks.register("printUnstableVersion") {
     }
 }
 
+// Some unit tests read files off disk: res/values*/strings.xml, because the app's own resources
+// are not on a plain JVM test's classpath and nothing here runs Robolectric, and the seeded
+// fixtures, which live beside the mise task that pushes them. Gradle cannot see those inputs by
+// itself, so a changed string or fixture would leave the tests UP-TO-DATE and the check would
+// pass without running them. Declared here rather than worked around in the tests.
+tasks.withType<Test>().configureEach {
+    inputs.dir(layout.projectDirectory.dir("src/main/res"))
+        .withPropertyName("appResources")
+        .withPathSensitivity(PathSensitivity.RELATIVE)
+    inputs.files(rootProject.layout.projectDirectory.files(
+        "evchargepilot-trips.json",
+        "evchargepilot-battery-ledger.json",
+    )).withPropertyName("seededFixtures").withPathSensitivity(PathSensitivity.RELATIVE)
+}
+
 dependencies {
     implementation(project(":evhardware"))
     implementation(libs.androidx.core.ktx)

app/src/main/res/values-fr/strings.xml

@@ -191,7 +191,7 @@
     <string name="energy_breakdown_charge_verdict_climate">Les portions parcourues climatisation en marche ont coûté plus de charge que vos trajets habituels.</string>
     <string name="energy_breakdown_charge_verdict_other">Un résiduel se distingue, mais les preuves disponibles ne permettent pas de l\'attribuer à un consommateur précis.</string>
     <string name="energy_breakdown_charge_rate">Sur ce trajet, 1 %% de charge a couvert environ %1$.1f km. La charge hors portions modélisées reste sur sa propre ligne.</string>
-    <string name="energy_breakdown_charge_untrained">Pas encore assez de conduite enregistrée pour ajuster le modèle de charge de cette voiture : il faut douze portions d\'au moins 2 %% et 2 km, sur une plage de vitesses et de températures. Aucune estimation n\'est affichée à la place.</string>
+    <string name="energy_breakdown_charge_untrained" formatted="false">Pas encore assez de conduite enregistrée pour ajuster le modèle de charge de cette voiture : il faut douze portions d\'au moins 2 % et 2 km, sur une plage de vitesses et de températures. Aucune estimation n\'est affichée à la place.</string>
     <string name="energy_breakdown_charge_no_interval">Ce trajet ne comporte aucune portion avec une vitesse, une température extérieure et une lecture de charge dont le modèle puisse parler.</string>
     <string name="energy_breakdown_charge_too_small">La jauge n\'a pas bougé de plus de deux crans sur ce trajet. Répartir cela entre conduite et reste reviendrait à répartir la résolution de la jauge.</string>
     <string name="action_speed_what_if">Comparer les vitesses</string>
@@ -464,7 +464,7 @@ Consommation %6$s %% par km</string>
     <string name="battery_health_declared">Votre valeur déclarée : %1$.0f %% de %2$.1f kWh.</string>
     <string name="battery_health_calibration_settled">Stable. La jauge a vu une charge complète il y a %1$.0f jours, et c’est là-dessus qu’elle se recale.</string>
     <string name="battery_health_calibration_watch">À surveiller. Dernière charge complète il y a %1$.0f jours.</string>
-    <string name="battery_health_calibration_re_anchor">Une charge complète aiderait. Charger à 100 %% et laisser la voiture branchée jusqu’à l’arrêt du courant est ce qui permet au pack de recaler son estimation de charge.</string>
+    <string name="battery_health_calibration_re_anchor" formatted="false">Une charge complète aiderait. Charger à 100 % et laisser la voiture branchée jusqu’à l’arrêt du courant est ce qui permet au pack de recaler son estimation de charge.</string>
     <string name="battery_health_calibration_never_full">Cette application n’a jamais vu cette voiture chargée au-dessus de %1$.0f %%.</string>
     <string name="battery_health_calibration_steps">%1$d saut(s) de charge que rien n’explique, le plus grand de %2$.0f points à l’arrêt. C’est la jauge qui se réestime, pas le pack qui se vide.</string>
     <string name="battery_health_calibration_cycles">%1$.1f cycles complets équivalents depuis.</string>

app/src/main/res/values/strings.xml

@@ -195,7 +195,7 @@
     <string name="energy_breakdown_charge_verdict_climate">The stretches driven with the climate on cost more charge than your usual trips do.</string>
     <string name="energy_breakdown_charge_verdict_other">A residual is distinguishable, but the available evidence cannot assign it to a separate consumer.</string>
     <string name="energy_breakdown_charge_rate">On this trip 1 %% of charge ran about %1$.1f km. Charge outside the modelled stretches stays in its own row.</string>
-    <string name="energy_breakdown_charge_untrained">Not enough recorded driving yet to fit this car\'s charge model: it needs twelve stretches of at least 2 %% and 2 km, across a range of speeds and temperatures. Nothing is estimated in its place.</string>
+    <string name="energy_breakdown_charge_untrained" formatted="false">Not enough recorded driving yet to fit this car\'s charge model: it needs twelve stretches of at least 2 % and 2 km, across a range of speeds and temperatures. Nothing is estimated in its place.</string>
     <string name="energy_breakdown_charge_no_interval">This trip has no stretch with a speed, an outside temperature and a charge reading the model can speak about.</string>
     <string name="energy_breakdown_charge_too_small">The gauge moved two steps or less across this trip. Splitting that between driving and everything else would be splitting the gauge\'s own resolution.</string>
     <string name="action_speed_what_if">Speed comparison</string>
@@ -473,7 +473,7 @@ Spending %6$s %% per km</string>
     <string name="battery_health_declared">Your declared figure: %1$.0f %% of %2$.1f kWh.</string>
     <string name="battery_health_calibration_settled">Settled. The gauge saw a full charge %1$.0f days ago, which is what it corrects itself against.</string>
     <string name="battery_health_calibration_watch">Worth watching. The last full charge was %1$.0f days ago.</string>
-    <string name="battery_health_calibration_re_anchor">A full charge would help. Charging to 100 %% and leaving the car plugged in until it stops drawing is what lets the pack re-anchor its own charge estimate.</string>
+    <string name="battery_health_calibration_re_anchor" formatted="false">A full charge would help. Charging to 100 % and leaving the car plugged in until it stops drawing is what lets the pack re-anchor its own charge estimate.</string>
     <string name="battery_health_calibration_never_full">This app has never seen this car charged above %1$.0f %%.</string>
     <string name="battery_health_calibration_steps">%1$d charge step(s) nothing explains, the largest %2$.0f points while parked. That is the gauge re-estimating, not the pack losing charge.</string>
     <string name="battery_health_calibration_cycles">%1$.1f equivalent full cycles since then.</string>

app/src/test/java/com/evsuite/chargepilot/StringPercentTest.kt

@@ -0,0 +1,33 @@
+package com.evsuite.chargepilot
+
+import java.io.File
+import javax.xml.parsers.DocumentBuilderFactory
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+/**
+ * `%%` is an escape, and only a formatted string is ever unescaped: `getString(id)` hands back the
+ * two characters as they are, which is how the battery page came to offer "Charging to 100 %%".
+ * A string carrying `%%` and no `%n$` argument is therefore always one of two bugs — a doubled
+ * sign shown to the driver, or an argument that was meant to be there and is not. Both locales are
+ * checked, because a translation is where the escape survives longest.
+ */
+class StringPercentTest {
+    @Test
+    fun `an escaped percent only appears in a string that is formatted`() {
+        val offenders = LOCALES.flatMap { locale ->
+            val file = File("src/main/res/$locale/strings.xml")
+            val root = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(file)
+            val strings = root.getElementsByTagName("string")
+            (0 until strings.length).map { strings.item(it) }
+                .filter { it.textContent.contains("%%") && !ARGUMENT.containsMatchIn(it.textContent) }
+                .map { "$locale/${it.attributes.getNamedItem("name").nodeValue}" }
+        }
+        assertEquals(emptyList<String>(), offenders)
+    }
+
+    private companion object {
+        val LOCALES = listOf("values", "values-fr")
+        val ARGUMENT = Regex("""%\d+\$""")
+    }
+}