add ThemeInstrumentedTest to verify theme settings and functionality

Author: 314systems

app/src/androidTest/kotlin/com/vrem/wifianalyzer/MainInstrumentedTest.kt

@@ -115,4 +115,9 @@ class MainInstrumentedTest {
     fun settings() {
         SettingsInstrumentedTest().run()
     }
+
+    @Test
+    fun theme() {
+        ThemeInstrumentedTest().run()
+    }
 }

app/src/androidTest/kotlin/com/vrem/wifianalyzer/ThemeInstrumentedTest.kt

@@ -0,0 +1,66 @@
+/*
+ * WiFiAnalyzer
+ * Copyright (C) 2026 VREM Software Development <VREMSoftwareDevelopment@gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ */
+package com.vrem.wifianalyzer
+
+import androidx.appcompat.app.AppCompatDelegate
+import androidx.test.espresso.Espresso.onView
+import androidx.test.espresso.Espresso.pressBack
+import androidx.test.espresso.action.ViewActions.click
+import androidx.test.espresso.assertion.ViewAssertions.matches
+import androidx.test.espresso.matcher.ViewMatchers.isDisplayed
+import androidx.test.espresso.matcher.ViewMatchers.withText
+import org.junit.Assert.assertEquals
+
+internal class ThemeInstrumentedTest : Runnable {
+    override fun run() {
+        verifyThemeSettings()
+
+        listOf(
+            "Dark" to AppCompatDelegate.MODE_NIGHT_YES,
+            "Light" to AppCompatDelegate.MODE_NIGHT_NO,
+            "System" to AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM,
+            "Black" to AppCompatDelegate.MODE_NIGHT_YES,
+        ).forEach { (themeName, expectedNightMode) ->
+            changeThemeAndVerify(themeName, expectedNightMode)
+        }
+    }
+
+    private fun verifyThemeSettings() {
+        selectMenuItem(R.id.nav_drawer_settings, "Settings")
+        scrollToAndVerify("Theme")
+        pressBack()
+    }
+
+    private fun changeThemeAndVerify(
+        themeName: String,
+        expectedNightMode: Int,
+    ) {
+        selectMenuItem(R.id.nav_drawer_settings, "Settings")
+        scrollToAndVerify("Theme")
+        onView(withText("Theme")).perform(click())
+        pauseShort()
+        onView(withText(themeName)).check(matches(isDisplayed()))
+        onView(withText(themeName)).perform(click())
+        pauseShort()
+        assertEquals(
+            "Theme $themeName should set night mode to $expectedNightMode",
+            expectedNightMode,
+            AppCompatDelegate.getDefaultNightMode(),
+        )
+    }
+}