test(widgets): add JVM unit and composable tests for ScaleBar

maps-compose-widgets/build.gradle.kts

@@ -58,6 +58,12 @@ android {
             enableAndroidTestCoverage = true
         }
     }
+
+    testOptions {
+        unitTests {
+            isIncludeAndroidResources = true
+        }
+    }
 }
 
 kotlin {
@@ -96,9 +102,24 @@ dependencies {
     api(libs.maps.ktx.utils)
 
     testImplementation(libs.test.junit)
+    testImplementation(libs.robolectric)
+    testImplementation(libs.truth)
+    testImplementation(libs.mockk)
+    testImplementation(libs.androidx.test.compose.ui)
+    testImplementation(libs.androidx.activity.compose)
+    testImplementation(libs.androidx.test.core)
+    testImplementation(libs.kotlinx.coroutines.test)
+    testImplementation(libs.maps.robolectric.shadows)
+
     androidTestImplementation(platform(libs.androidx.compose.bom))
     androidTestImplementation(libs.androidx.test.espresso)
     androidTestImplementation(libs.androidx.test.junit.ktx)
     androidTestImplementation(libs.mockk.android)
     androidTestImplementation(libs.truth)
 }
+
+tasks.withType<Test>().configureEach {
+    javaLauncher.set(javaToolchains.launcherFor {
+        languageVersion.set(JavaLanguageVersion.of(21))
+    })
+}

maps-compose-widgets/src/debug/AndroidManifest.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+ Copyright 2026 Google LLC
+
+ 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.
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <application>
+        <activity
+            android:name="androidx.activity.ComponentActivity"
+            android:exported="true" />
+    </application>
+</manifest>

maps-compose-widgets/src/test/java/com/google/maps/android/compose/widgets/ScaleBarTest.kt

@@ -0,0 +1,125 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * 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 com.google.maps.android.compose.widgets
+
+import android.graphics.Point
+import androidx.activity.ComponentActivity
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.test.junit4.AndroidComposeTestRule
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import androidx.compose.ui.unit.Density
+import androidx.compose.ui.unit.dp
+import androidx.test.ext.junit.rules.ActivityScenarioRule
+import com.google.android.gms.maps.Projection
+import com.google.android.gms.maps.model.CameraPosition
+import com.google.android.gms.maps.model.LatLng
+import com.google.android.maps.robolectric.annotation.EnableMapsShadows
+import com.google.common.truth.Truth.assertThat
+import com.google.maps.android.compose.CameraPositionState
+import com.google.maps.android.ktx.utils.sphericalDistance
+import io.mockk.every
+import io.mockk.mockk
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+// [START maps_compose_widgets_scale_bar_test]
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [34])
+@EnableMapsShadows
+internal class ScaleBarTest {
+
+    @get:Rule
+    internal val composeTestRule: AndroidComposeTestRule<ActivityScenarioRule<ComponentActivity>, ComponentActivity> =
+        createAndroidComposeRule<ComponentActivity>()
+
+    @Test
+    internal fun testCalculateDistance_computesExpectedCanvasDistance(): Unit {
+        val projection = mockk<Projection>(relaxed = true)
+        val density = Density(1f, 1f)
+        val width = 100.dp
+
+        val startPoint = Point(0, 0)
+        val endPoint = Point(width.value.toInt(), 0)
+
+        val startLatLng = LatLng(0.0, 0.0)
+        val endLatLng = LatLng(0.0, 0.001)
+
+        every { projection.fromScreenLocation(startPoint) } returns startLatLng
+        every { projection.fromScreenLocation(endPoint) } returns endLatLng
+
+        val expectedDistance = startLatLng.sphericalDistance(endLatLng)
+        val expectedResult = (expectedDistance * 8 / 9).toInt()
+
+        val result = calculateDistance(projection, width, density)
+
+        assertThat(result).isEqualTo(expectedResult)
+    }
+
+    @Test
+    internal fun testUnitConversions_toFeetAndToMiles(): Unit {
+        val meters = 1609.344 // 1 mile in meters
+        val feet = meters.toFeet()
+        assertThat(feet).isWithin(1.0).of(5280.0)
+
+        val miles = feet.toMiles()
+        assertThat(miles).isWithin(0.01).of(1.0)
+    }
+
+    @Test
+    internal fun testScaleBar_rendersWithoutCrashing(): Unit {
+        val cameraState = CameraPositionState(
+            position = CameraPosition.fromLatLngZoom(LatLng(37.7749, -122.4194), 12f)
+        )
+
+        composeTestRule.setContent {
+            ScaleBar(
+                cameraPositionState = cameraState,
+                width = 80.dp,
+                height = 50.dp,
+                textColor = Color.Black,
+                lineColor = Color.Blue,
+                shadowColor = Color.White
+            )
+        }
+
+        composeTestRule.waitForIdle()
+    }
+
+    @Test
+    internal fun testDisappearingScaleBar_rendersAndRespondsToCameraPosition(): Unit {
+        val cameraState = CameraPositionState(
+            position = CameraPosition.fromLatLngZoom(LatLng(37.7749, -122.4194), 10f)
+        )
+
+        composeTestRule.setContent {
+            DisappearingScaleBar(
+                cameraPositionState = cameraState,
+                visibilityDurationMillis = 500
+            )
+        }
+
+        composeTestRule.waitForIdle()
+
+        // Update camera position to trigger visibility LaunchedEffect
+        cameraState.position = CameraPosition.fromLatLngZoom(LatLng(37.7749, -122.4194), 14f)
+        composeTestRule.waitForIdle()
+    }
+}
+// [END maps_compose_widgets_scale_bar_test]