diff --git a/core/tests/coretests/AndroidManifest.xml b/core/tests/coretests/AndroidManifest.xml
index f6216fa659152..a73ebc2630b9b 100644
--- a/core/tests/coretests/AndroidManifest.xml
+++ b/core/tests/coretests/AndroidManifest.xml
@@ -1685,12 +1685,16 @@
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diff --git a/core/tests/coretests/src/android/content/res/FontScaleConverterActivityTest.java b/core/tests/coretests/src/android/content/res/FontScaleConverterActivityTest.java
new file mode 100644
index 0000000000000..55ef854081328
--- /dev/null
+++ b/core/tests/coretests/src/android/content/res/FontScaleConverterActivityTest.java
@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.content.res;
+
+import static androidx.test.espresso.Espresso.onView;
+import static androidx.test.espresso.assertion.ViewAssertions.matches;
+import static androidx.test.espresso.matcher.ViewMatchers.withId;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.app.Activity;
+import android.compat.testing.PlatformCompatChangeRule;
+import android.os.Bundle;
+import android.platform.test.annotations.Presubmit;
+import android.provider.Settings;
+import android.view.View;
+import android.widget.TextView;
+
+import androidx.test.core.app.ActivityScenario;
+import androidx.test.espresso.matcher.BoundedMatcher;
+import androidx.test.ext.junit.rules.ActivityScenarioRule;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.LargeTest;
+import androidx.test.platform.app.InstrumentationRegistry;
+
+import com.android.compatibility.common.util.ShellIdentityUtils;
+import com.android.frameworks.coretests.R;
+
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestRule;
+import org.junit.runner.RunWith;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Test for verifying non-linear font scaling behavior.
+ * Build/Install/Run:
+ * atest FrameworksCoreTests:android.content.res.FontScaleConverterActivityTest
+ */
+@RunWith(AndroidJUnit4.class)
+@LargeTest
+@Presubmit
+public class FontScaleConverterActivityTest {
+ @Rule
+ public ActivityScenarioRule rule = new ActivityScenarioRule<>(TestActivity.class);
+ @Rule
+ public TestRule compatChangeRule = new PlatformCompatChangeRule();
+
+ private float mOriginalFontScale = Float.MIN_VALUE;
+
+ @Before
+ public void setup() {
+ mOriginalFontScale = Settings.System.getFloat(
+ InstrumentationRegistry.getInstrumentation().getContext().getContentResolver(),
+ Settings.System.FONT_SCALE,
+ Float.MIN_VALUE
+ );
+ }
+
+ @After
+ public void teardown() {
+ if (mOriginalFontScale != Float.MIN_VALUE) {
+ setSystemFontScale(mOriginalFontScale);
+ }
+ }
+
+ @Test
+ public void testFontsScaleNonLinearly() {
+ final ActivityScenario scenario = rule.getScenario();
+
+ setSystemFontScale(2f);
+
+ var densityRef = new AtomicReference();
+ scenario.onActivity(activity -> {
+ densityRef.compareAndSet(null, activity.getResources().getDisplayMetrics().density);
+ });
+ var density = densityRef.get();
+ assertThat(density).isNotNull();
+
+ onView(withId(R.id.text8sp)).check(matches(withTextSizeInRange(
+ 15f * density,
+ 16f * density
+ )));
+ onView(withId(R.id.text18sp)).check(matches(withTextSizeInRange(
+ 20f * density,
+ 36f * density
+ )));
+ onView(withId(R.id.text35sp)).check(matches(withTextSizeInRange(
+ 35 * density,
+ 60 * density
+ )));
+ }
+
+ @Test
+ public void testOnConfigurationChanged_doesNotCrash() {
+ final ActivityScenario scenario = rule.getScenario();
+
+ scenario.onActivity(activity -> {
+ var config = new Configuration(activity.getResources().getConfiguration());
+ config.fontScale = 1.2f;
+
+ activity.onConfigurationChanged(config);
+ activity.finish();
+ });
+ }
+
+ @Test
+ public void testUpdateConfiguration_doesNotCrash() {
+ final ActivityScenario scenario = rule.getScenario();
+
+ scenario.onActivity(activity -> {
+ activity.updateConfiguration();
+ activity.finish();
+ });
+ }
+
+ private static void setSystemFontScale(float fontScale) {
+ ShellIdentityUtils.invokeWithShellPermissions(() -> {
+ Settings.System.putFloat(
+ InstrumentationRegistry.getInstrumentation().getContext().getContentResolver(),
+ Settings.System.FONT_SCALE,
+ fontScale
+ );
+ });
+ }
+
+ private Matcher withTextSizeInRange(float sizeStartPx, float sizeEndPx) {
+ return new BoundedMatcher<>(TextView.class) {
+ private static final float TOLERANCE = 0.05f;
+
+ @Override
+ public void describeMismatch(Object item, Description description) {
+ super.describeMismatch(item, description);
+ description.appendText("was ").appendValue(((TextView) item).getTextSize());
+ }
+
+ @Override
+ public void describeTo(Description description) {
+ description.appendText("withTextSize between " + sizeStartPx + " and " + sizeEndPx);
+ }
+
+ @Override
+ protected boolean matchesSafely(TextView textView) {
+ var textSize = textView.getTextSize();
+ return sizeStartPx - TOLERANCE < textSize && textSize < sizeEndPx + TOLERANCE;
+ }
+ };
+ }
+
+ /** Test Activity */
+ public static class TestActivity extends Activity {
+ final Configuration mConfig = new Configuration();
+
+ @Override
+ protected void onCreate(Bundle savedInstanceState) {
+ super.onCreate(savedInstanceState);
+ getWindow().getDecorView().setKeepScreenOn(true);
+ setShowWhenLocked(true);
+ setTurnScreenOn(true);
+
+ setContentView(R.layout.font_scale_converter_activity);
+ }
+
+ public Configuration updateConfiguration() {
+ Settings.System.getConfiguration(getContentResolver(), mConfig);
+ return mConfig;
+ }
+ }
+}