(#169) Added error message in case needle is way to large for haystack

Author: svettwer

lib/match-result.class.ts

@@ -4,5 +4,6 @@ export class MatchResult {
   constructor(
     public readonly confidence: number,
     public readonly location: Region,
+    public readonly error?: Error
   ) {}
 }

lib/provider/opencv/__mocks__/fat-needle.png

@@ -91,4 +91,23 @@ describe("Template-matching finder", () => {
             .rejects
             .toThrowError(`Failed to load ${pathToHaystack}. Reason: 'Failed to load image from '${pathToHaystack}''.`);
     });
+
+    it("findMatch should reject, if needle was way lager than the haystack", async () => {
+        // GIVEN
+        const imageLoader = new ImageReader();
+        const SUT = new TemplateMatchingFinder();
+        const haystackPath = path.resolve(__dirname, "./__mocks__/mouse.png");
+        const needlePath = path.resolve(__dirname, "./__mocks__/fat-needle.png");
+        const haystack = await imageLoader.load(haystackPath);
+        const minConfidence = 0.99;
+        const searchRegion = new Region(0, 0, haystack.width, haystack.height);
+        const matchRequest = new MatchRequest(haystack, needlePath, searchRegion, minConfidence);
+        const expectedRejection = "The provided image sample is larger than the provided search region"
+
+        // WHEN
+        const findMatchPromise = SUT.findMatch(matchRequest);
+
+        // THEN
+        await expect(findMatchPromise).rejects.toEqual(expectedRejection)
+    });
 });

lib/provider/opencv/template-matching-finder.class.spec.ts

@@ -101,7 +101,8 @@ export default class TemplateMatchingFinder implements FinderInterface {
                             0,
                             0,
                             0
-                        )
+                        ),
+                        new Error("The provided image sample is larger than the provided search region")
                     );
                 }
                 const matchResult = await matchImages(haystack, needle);
@@ -120,7 +121,8 @@ export default class TemplateMatchingFinder implements FinderInterface {
                                 0,
                                 0,
                                 0
-                            )
+                            ),
+                            new Error("The provided image sample is larger than the provided search region")
                         );
                     }
                     const matchResult = await matchImages(haystack, scaledNeedle);
@@ -142,7 +144,8 @@ export default class TemplateMatchingFinder implements FinderInterface {
                                 0,
                                 0,
                                 0
-                            )
+                            ),
+                            new Error("The provided image sample is larger than the provided search region")
                         );
                     }
                     const matchResult = await matchImages(scaledHaystack, needle);
@@ -182,7 +185,11 @@ export default class TemplateMatchingFinder implements FinderInterface {
                     matches.sort((a, b) => a.confidence - b.confidence);
                     const bestMatch = matches.pop();
                     if (bestMatch) {
-                        reject(`No match with required confidence ${matchRequest.confidence}. Best match: ${bestMatch.confidence} at ${bestMatch.location}`)
+                        if(bestMatch.error) {
+                            reject(bestMatch.error.message)
+                        }else {
+                            reject(`No match with required confidence ${matchRequest.confidence}. Best match: ${bestMatch.confidence} at ${bestMatch.location}`)
+                        }
                     } else {
                         reject(`Unable to locate ${matchRequest.pathToNeedle}, no match!`);
                     }

lib/provider/opencv/template-matching-finder.class.ts

@@ -5,7 +5,8 @@ export class ScaledMatchResult extends MatchResult {
   constructor(public readonly confidence: number,
               public readonly scale: number,
               public readonly location: Region,
+              public readonly error?: Error
   ) {
-    super(confidence, location);
+    super(confidence, location, error);
   }
 }