Rewrite images comparison tests using images input

.gitignore

@@ -3,3 +3,4 @@
 /Packages
 /*.xcodeproj
 xcuserdata/
+.swiftpm

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.1
+// swift-tools-version:5.3
 
 /*
  SUITCase

Sources/SUITCase/Assets.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/de_iPhone_X_dna_unexpected.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "de_iPhone_X_dna_unexpected.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/dna_difference.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "dna_difference.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_average_difference.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_average_difference.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_average_reference.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_average_reference.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_average_unexpected.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_average_unexpected.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_dna_reference.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_dna_reference.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_greyscale_difference.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_greyscale_difference.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_greyscale_reference.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_greyscale_reference.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_greyscale_unexpected.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_greyscale_unexpected.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_strict_difference.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_strict_difference.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_strict_reference.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_strict_reference.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_strict_unexpected.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_strict_unexpected.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_tolerance_difference.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_tolerance_difference.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_tolerance_reference.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_tolerance_reference.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/Assets.xcassets/en_iPhone_X_tolerance_unexpected.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "en_iPhone_X_tolerance_unexpected.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sources/SUITCase/SUITCase+getImagePaths.swift

@@ -25,7 +25,7 @@ extension SUITCase {
 
     // swiftlint:disable large_tuple
     func getImagePaths(withLabel customLabel: String?,
-                       imageSize: CGSize) throws -> (reference: String, suggested: String, unexpected: String) {
+                       imageSize: CGSize) throws -> (reference: String, suggested: String, unexpected: String, difference: String) {
         guard let imagesFolder = SUITCase.screenshotComparisonImagesFolder,
             let testClassName = testClassName,
             var testName = testName,
@@ -50,11 +50,11 @@ extension SUITCase {
         }
 
         var imagePaths: [String] = []
-        for subfolder in ["Reference", "Suggested", "Unexpected"] {
+        for subfolder in ["Reference", "Suggested", "Unexpected", "Difference"] {
             let fullPath = [imagesFolder, subfolder, filePath].joined(separator: "/")
             imagePaths.append(fullPath)
         }
 
-        return (imagePaths[0], imagePaths[1], imagePaths[2])
+        return (imagePaths[0], imagePaths[1], imagePaths[2], imagePaths[3])
     }
 }

Sources/SUITCase/SUITCase+verifyScreenshot.swift

@@ -141,9 +141,16 @@ extension SUITCase {
             addNote("Collected and reference screenshots are similar")
         } else {
             addImage(referenceImage, name: "Reference image")
-            addImage(difference.image.uiImage, name: "Difference image")
+            let differenceImage = difference.image.uiImage
+            addImage(differenceImage, name: "Difference image")
             if difference.value > threshold {
                 try actualImage.writePNG(filePath: filePaths.unexpected)
+
+                if savesDifferenceImages {
+                    try differenceImage.writePNG(filePath: filePaths.difference)
+                    addNote("Difference image saving is enabled. Saved difference image")
+                }
+
                 throw VerifyScreenshotError.noMatch
             }
         }

Sources/SUITCase/SUITCase.swift

@@ -27,4 +27,6 @@ open class SUITCase: XCTestCase {
     public var screenshotComparisonGlobalThreshold = 0.01
     /// Changes current reference images naming strategy.
     public var screenshotComparisonNamingStrategy = ScreenshotComparisonNamingStrategies.imageSize
+    /// Indicates weather difference images should be saved along with collected (unexpected) images
+    public var savesDifferenceImages = false
 }