Add tolerance to Picasso tests

google · Mar 12, 2021 · c11e0e9 · c11e0e9
1 parent ff89179
commit c11e0e9
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Showing 3 changed files with 22 additions and 14 deletions.
diff --git a/imageloading-testutils/build.gradle b/imageloading-testutils/build.gradle
@@ -72,8 +72,6 @@ dependencies {
 
     implementation Libs.AndroidX.coreKtx
 
-    implementation Libs.AndroidX.Compose.runtime
-    implementation Libs.AndroidX.Compose.foundation
     implementation Libs.AndroidX.Compose.ui
 
     implementation Libs.Kotlin.stdlib
@@ -82,6 +80,8 @@ dependencies {
     api Libs.OkHttp.mockWebServer
     implementation Libs.OkHttp.okhttp
 
+    implementation Libs.truth
+
     implementation Libs.Coroutines.test
 
     implementation Libs.AndroidX.Compose.test

diff --git a/...tutils/src/main/java/dev/chrisbanes/accompanist/imageloading/test/ImageAssetAssertions.kt b/...tutils/src/main/java/dev/chrisbanes/accompanist/imageloading/test/ImageAssetAssertions.kt
@@ -18,16 +18,18 @@ package dev.chrisbanes.accompanist.imageloading.test
 
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.ImageBitmap
-import androidx.compose.ui.graphics.toArgb
 import androidx.compose.ui.graphics.toPixelMap
-import org.junit.Assert.assertEquals
+import com.google.common.truth.Truth.assertThat
 
 /**
  * Assert that all of the pixels in this image as of the [expected] color.
  */
-fun ImageBitmap.assertPixels(expected: Color) {
-    val expectedArgb = expected.toArgb()
+fun ImageBitmap.assertPixels(expected: Color, tolerance: Float = 0.0001f) {
     toPixelMap().buffer.forEach { pixel ->
-        assertEquals(expectedArgb, pixel)
+        val color = Color(pixel)
+        assertThat(color.red).isWithin(tolerance).of(expected.red)
+        assertThat(color.green).isWithin(tolerance).of(expected.green)
+        assertThat(color.blue).isWithin(tolerance).of(expected.blue)
+        assertThat(color.alpha).isWithin(tolerance).of(expected.alpha)
     }
 }
diff --git a/picasso/src/androidTest/java/dev/chrisbanes/accompanist/picasso/PicassoTest.kt b/picasso/src/androidTest/java/dev/chrisbanes/accompanist/picasso/PicassoTest.kt
@@ -64,6 +64,12 @@ import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
 import java.util.concurrent.TimeUnit
 
+/**
+ * This 4% tolerance is to work around scaling issues, which causes very slight color differences
+ * when using Picasso.
+ */
+private const val PixelTolerance = 0.04f
+
 @LargeTest
 @RunWith(JUnit4::class)
 class PicassoTest {
@@ -129,7 +135,7 @@ class PicassoTest {
             .assertHeightIsEqualTo(128.dp)
             .assertIsDisplayed()
             .captureToImage()
-            .assertPixels(Color.Red)
+            .assertPixels(Color.Red, PixelTolerance)
     }
 
     @OptIn(ExperimentalCoroutinesApi::class)
@@ -158,7 +164,7 @@ class PicassoTest {
             .assertHeightIsEqualTo(128.dp)
             .assertIsDisplayed()
             .captureToImage()
-            .assertPixels(Color.Red)
+            .assertPixels(Color.Red, PixelTolerance)
 
         // Now switch the data URI to the blue drawable
         data = server.url("/blue")
@@ -172,7 +178,7 @@ class PicassoTest {
             .assertHeightIsEqualTo(128.dp)
             .assertIsDisplayed()
             .captureToImage()
-            .assertPixels(Color.Blue)
+            .assertPixels(Color.Blue, PixelTolerance)
     }
 
     @OptIn(ExperimentalCoroutinesApi::class)
@@ -256,7 +262,7 @@ class PicassoTest {
         composeTestRule.onNodeWithTag(TestTags.Image)
             .assertIsDisplayed()
             .captureToImage()
-            .assertPixels(Color.Red)
+            .assertPixels(Color.Red, PixelTolerance)
     }
 
     @SdkSuppress(minSdkVersion = 26) // captureToImage
@@ -292,7 +298,7 @@ class PicassoTest {
         composeTestRule.onNodeWithTag(TestTags.Image)
             .assertIsDisplayed()
             .captureToImage()
-            .assertPixels(Color.Red)
+            .assertPixels(Color.Red, PixelTolerance)
     }
 
     @Test
@@ -407,7 +413,7 @@ class PicassoTest {
         composeTestRule.onNodeWithTag(TestTags.Image)
             .assertIsDisplayed()
             .captureToImage()
-            .assertPixels(Color.Cyan)
+            .assertPixels(Color.Cyan, PixelTolerance)
     }
 
     @Test
@@ -480,7 +486,7 @@ class PicassoTest {
         composeTestRule.onNodeWithTag(TestTags.Image)
             .assertIsDisplayed()
             .captureToImage()
-            .assertPixels(Color.Red)
+            .assertPixels(Color.Red, PixelTolerance)
     }
 
     @Test(expected = IllegalArgumentException::class)