Merge pull request #209 from Shopify/206-generate-diffs

Add ability for Testify to generate companion diff images for failed tests

Author: DanielJette

CHANGELOG.md

@@ -4,6 +4,10 @@
 
 ### Library
 
+#### Added
+
+- Added `TestifyFeatures.GenerateDiffs`. When enabled, will output a `.diff.png` alongside existing baseline images. These images are high-contrast images where each difference, regardless of how minor, are indicated in red against a black background. See the `generateDiffs` test in `ScreenshotRuleExampleTests` for an example. Diff images will be pulled from the device when running `screenshotPull`.
+
 #### Changes
 
 - Optional constructor argument enableReporter added to ScreenshotRule. Allows you to specify whether to run the reporter for this test rule.

Library/build.gradle

@@ -78,4 +78,3 @@ android {
 
 apply from: "bintray.build.gradle"
 apply from: '../ktlint.gradle'
-

Library/src/main/java/com/shopify/testify/ScreenshotRule.kt

@@ -75,6 +75,7 @@ import com.shopify.testify.internal.modification.HidePasswordViewModification
 import com.shopify.testify.internal.modification.HideScrollbarsViewModification
 import com.shopify.testify.internal.modification.HideTextSuggestionsViewModification
 import com.shopify.testify.internal.modification.SoftwareRenderViewModification
+import com.shopify.testify.internal.processor.diff.HighContrastDiff
 import com.shopify.testify.internal.output.OutputFileUtility
 import com.shopify.testify.report.ReportSession
 import com.shopify.testify.report.Reporter
@@ -544,6 +545,13 @@ open class ScreenshotRule<T : Activity> @JvmOverloads constructor(
                         screenshotUtility.deleteBitmap(activity, outputFileName)
                     )
                 } else {
+                    if (TestifyFeatures.GenerateDiffs.isEnabled(activity)) {
+                        HighContrastDiff()
+                            .name(outputFileName)
+                            .baseline(baselineBitmap)
+                            .current(currentBitmap)
+                            .generate(context = activity)
+                    }
                     if (isRecordMode()) {
                         instrumentationPrintln(
                             "\n\t✓ " + 27.toChar() + "[36mRecording baseline for " + testName +

Library/src/main/java/com/shopify/testify/ScreenshotUtility.kt

@@ -59,7 +59,7 @@ class ScreenshotUtility {
             return options
         }
 
-    private fun saveBitmapToFile(context: Context, bitmap: Bitmap?, outputFilePath: String): Boolean {
+    fun saveBitmapToFile(context: Context, bitmap: Bitmap?, outputFilePath: String): Boolean {
         if (bitmap == null) {
             return false
         }

Library/src/main/java/com/shopify/testify/TestifyFeatures.kt

@@ -32,6 +32,7 @@ enum class TestifyFeatures(internal val tags: List<String>, private val defaultV
     ExampleDisabledFeature(listOf("testify-disabled")),
 
     Reporter(listOf("testify-reporter")),
+    GenerateDiffs(listOf("testify-generate-diffs"), defaultValue = false),
     Locale(listOf("testify-experimental-locale"), defaultValue = true),
     CanvasCapture(listOf("testify-canvas-capture")),
     PixelCopyCapture(listOf("testify-experimental-capture", "testify-pixelcopy-capture"));

Library/src/main/java/com/shopify/testify/internal/processor/diff/HighContrastDiff.kt

@@ -0,0 +1,52 @@
+package com.shopify.testify.internal.processor.diff
+
+import android.content.Context
+import android.graphics.Bitmap
+import android.graphics.Color
+import com.shopify.testify.ScreenshotUtility
+import com.shopify.testify.internal.output.OutputFileUtility
+import com.shopify.testify.internal.processor.ParallelPixelProcessor
+import com.shopify.testify.internal.processor.createBitmap
+
+class HighContrastDiff {
+
+    private lateinit var fileName: String
+    private lateinit var baselineBitmap: Bitmap
+    private lateinit var currentBitmap: Bitmap
+
+    fun generate(context: Context) {
+        val transformResult = ParallelPixelProcessor
+            .create()
+            .baseline(baselineBitmap)
+            .current(currentBitmap)
+            .transform { baselinePixel, currentPixel ->
+                if (baselinePixel == currentPixel) {
+                    Color.BLACK
+                } else {
+                    Color.RED
+                }
+            }
+
+        val screenshotUtility = ScreenshotUtility()
+        screenshotUtility.saveBitmapToFile(
+            context = context,
+            bitmap = transformResult.createBitmap(),
+            outputFilePath = OutputFileUtility().getOutputFilePath(context, "$fileName.diff")
+        )
+    }
+
+    fun name(outputFileName: String): HighContrastDiff {
+        fileName = outputFileName
+        return this
+    }
+
+    fun baseline(baselineBitmap: Bitmap): HighContrastDiff {
+        this.baselineBitmap = baselineBitmap
+        return this
+    }
+
+    fun current(currentBitmap: Bitmap): HighContrastDiff {
+        this.currentBitmap = currentBitmap
+        return this
+    }
+}

Plugins/Gradle/jar/Plugin-local.jar

@@ -37,6 +37,7 @@ import com.shopify.testify.TestifyFeatures
 import com.shopify.testify.annotation.ScreenshotInstrumentation
 import com.shopify.testify.annotation.TestifyLayout
 import com.shopify.testify.extensions.boundingBox
+import com.shopify.testify.internal.exception.ScreenshotIsDifferentException
 import com.shopify.testify.sample.test.TestHarnessActivity
 import com.shopify.testify.sample.test.TestHarnessActivity.Companion.EXTRA_TITLE
 import com.shopify.testify.sample.test.clientDetailsView
@@ -54,7 +55,8 @@ class ScreenshotRuleExampleTests {
      * [R.id.harness_root] is the topmost/root view in the hierarchy. Testify will load views in
      * this root.
      */
-    @get:Rule var rule = ScreenshotRule(
+    @get:Rule
+    var rule = ScreenshotRule(
         activityClass = TestHarnessActivity::class.java,
         launchActivity = false,
         rootViewId = R.id.harness_root
@@ -227,6 +229,25 @@ class ScreenshotRuleExampleTests {
             .assertSame()
     }
 
+
+    @TestifyLayout(R.layout.view_client_details)
+    @ScreenshotInstrumentation
+    @Test(expected = ScreenshotIsDifferentException::class)
+    fun generateDiffs() {
+        TestifyFeatures.GenerateDiffs.setEnabled(true)
+        rule.setViewModifications { harnessRoot ->
+            rule.activity.getViewState(name = "A Name").let {
+                val state = it.copy(
+                    name = "A Different Name",
+                    avatar = R.drawable.avatar2,
+                    heading = harnessRoot.context.getString(R.string.client_since, "2019")
+                )
+                harnessRoot.clientDetailsView.render(state)
+                rule.activity.title = state.name
+            }
+        }.assertSame()
+    }
+
     /**
      * Demonstrates Testify's ability to take a screenshot of a single view.
      *