Use image fingerprints in functional tests #122

README.md

@@ -669,6 +669,10 @@ A [guide for contributors](https://github.com/lovell/sharp/blob/master/CONTRIBUT
 
 ### Functional tests
 
+Where possible, the functional tests use gradient-based perceptual hashes
+based on [dHash](http://www.hackerfactor.com/blog/index.php?/archives/529-Kind-of-Like-That.html)
+to compare expected vs actual images.
+
 #### Coverage
 
 [![Test Coverage](https://coveralls.io/repos/lovell/sharp/badge.png?branch=master)](https://coveralls.io/r/lovell/sharp?branch=master)

test/fixtures/index.js

@@ -1,11 +1,42 @@
 'use strict';
 
 var path = require('path');
+var assert = require('assert');
+
+var sharp = require('../../index');
 
 var getPath = function(filename) {
   return path.join(__dirname, filename);
 };
 
+// Generates a 64-bit-as-binary-string image fingerprint
+// Based on the dHash gradient method - see http://www.hackerfactor.com/blog/index.php?/archives/529-Kind-of-Like-That.html
+var fingerprint = function(image, done) {
+  sharp(image)
+    .greyscale()
+    .normalise()
+    .resize(9, 8)
+    .ignoreAspectRatio()
+    .interpolateWith(sharp.interpolator.vertexSplitQuadraticBasisSpline)
+    .raw()
+    .toBuffer(function(err, data) {
+      if (err) {
+        done(err);
+      } else {
+        var fingerprint = '';
+        for (var col = 0; col < 8; col++) {
+          var gradient = 0;
+          for (var row = 0; row < 8; row++) {
+            var left = data[row * 8 + col];
+            var right = data[row * 8 + col + 1];
+            fingerprint = fingerprint + (left < right ? '1' : '0');
+          }
+        }
+        done(null, fingerprint);
+      }
+    });
+};
+
 module.exports = {
 
   inputJpg: getPath('2569067123_aca715a2ee_o.jpg'), // http://www.flickr.com/photos/grizdave/2569067123/
@@ -35,6 +66,30 @@ module.exports = {
   outputWebP: getPath('output.webp'),
   outputZoinks: getPath('output.zoinks'), // an 'unknown' file extension
 
-  path: getPath // allows tests to write files to fixtures directory (for testing with human eyes)
+  // Path for tests requiring human inspection
+  path: getPath,
+
+  // Path for expected output images
+  expected: function(filename) {
+    return getPath(path.join('expected', filename));
+  },
+
+  // Verify similarity of expected vs actual images via fingerprint
+  assertSimilar: function(expectedImage, actualImage, done) {
+    fingerprint(expectedImage, function(err, expectedFingerprint) {
+      if (err) throw err;
+      fingerprint(actualImage, function(err, actualFingerprint) {
+        if (err) throw err;
+        var distance = 0;
+        for (var i = 0; i < 64; i++) {
+          if (expectedFingerprint[i] !== actualFingerprint[i]) {
+            distance++;
+          }
+        }
+        assert.strictEqual(true, distance <= 5);  // ~7% threshold
+        done();
+      });
+    });
+  }
 
 };

test/unit/alpha.js

@@ -13,7 +13,12 @@ describe('Alpha transparency', function() {
     sharp(fixtures.inputPngWithTransparency)
       .flatten()
       .resize(400, 300)
-      .toFile(fixtures.path('output.flatten-black.jpg'), done);
+      .toBuffer(function(err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(400, info.width);
+        assert.strictEqual(300, info.height);
+        fixtures.assertSimilar(fixtures.expected('flatten-black.jpg'), data, done);
+      });
   });
 
   it('Flatten to RGB orange', function(done) {
@@ -21,7 +26,12 @@ describe('Alpha transparency', function() {
       .flatten()
       .background({r: 255, g: 102, b: 0})
       .resize(400, 300)
-      .toFile(fixtures.path('output.flatten-rgb-orange.jpg'), done);
+      .toBuffer(function(err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(400, info.width);
+        assert.strictEqual(300, info.height);
+        fixtures.assertSimilar(fixtures.expected('flatten-orange.jpg'), data, done);
+      });
   });
 
   it('Flatten to CSS/hex orange', function(done) {
@@ -29,7 +39,12 @@ describe('Alpha transparency', function() {
       .flatten()
       .background('#ff6600')
       .resize(400, 300)
-      .toFile(fixtures.path('output.flatten-hex-orange.jpg'), done);
+      .toBuffer(function(err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(400, info.width);
+        assert.strictEqual(300, info.height);
+        fixtures.assertSimilar(fixtures.expected('flatten-orange.jpg'), data, done);
+      });
   });
 
   it('Do not flatten', function(done) {

test/unit/crop.js

@@ -13,11 +13,11 @@ describe('Crop gravities', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 80)
       .crop(sharp.gravity.north)
-      .toFile(fixtures.path('output.gravity-north.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(320, info.width);
         assert.strictEqual(80, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('gravity-north.jpg'), data, done);
       });
   });
 
@@ -25,11 +25,11 @@ describe('Crop gravities', function() {
     sharp(fixtures.inputJpg)
       .resize(80, 320)
       .crop(sharp.gravity.east)
-      .toFile(fixtures.path('output.gravity-east.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(80, info.width);
         assert.strictEqual(320, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('gravity-east.jpg'), data, done);
       });
   });
 
@@ -37,11 +37,11 @@ describe('Crop gravities', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 80)
       .crop(sharp.gravity.south)
-      .toFile(fixtures.path('output.gravity-south.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(320, info.width);
         assert.strictEqual(80, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('gravity-south.jpg'), data, done);
       });
   });
 
@@ -49,11 +49,11 @@ describe('Crop gravities', function() {
     sharp(fixtures.inputJpg)
       .resize(80, 320)
       .crop(sharp.gravity.west)
-      .toFile(fixtures.path('output.gravity-west.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(80, info.width);
         assert.strictEqual(320, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('gravity-west.jpg'), data, done);
       });
   });
 
@@ -61,11 +61,11 @@ describe('Crop gravities', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 80)
       .crop(sharp.gravity.center)
-      .toFile(fixtures.path('output.gravity-center.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(320, info.width);
         assert.strictEqual(80, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('gravity-center.jpg'), data, done);
       });
   });
 
@@ -73,23 +73,18 @@ describe('Crop gravities', function() {
     sharp(fixtures.inputJpg)
       .resize(80, 320)
       .crop(sharp.gravity.centre)
-      .toFile(fixtures.path('output.gravity-centre.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(80, info.width);
         assert.strictEqual(320, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('gravity-centre.jpg'), data, done);
       });
   });
 
-  it('Invalid', function(done) {
-    var isValid = true;
-    try {
+  it('Invalid', function() {
+    assert.throws(function() {
       sharp(fixtures.inputJpg).crop(5);
-    } catch (err) {
-      isValid = false;
-    }
-    assert.strictEqual(false, isValid);
-    done();
+    });
   });
 
 });

test/unit/extract.js

@@ -12,22 +12,22 @@ describe('Partial image extraction', function() {
   it('JPEG', function(done) {
     sharp(fixtures.inputJpg)
       .extract(2, 2, 20, 20)
-      .toFile(fixtures.path('output.extract.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(20, info.width);
         assert.strictEqual(20, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('extract.jpg'), data, done);
       });
   });
 
   it('PNG', function(done) {
     sharp(fixtures.inputPng)
       .extract(300, 200, 400, 200)
-      .toFile(fixtures.path('output.extract.png'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(400, info.width);
         assert.strictEqual(200, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('extract.png'), data, done);
       });
   });
 
@@ -35,11 +35,11 @@ describe('Partial image extraction', function() {
     it('WebP', function(done) {
       sharp(fixtures.inputWebP)
         .extract(50, 100, 125, 200)
-        .toFile(fixtures.path('output.extract.webp'), function(err, info) {
+        .toBuffer(function(err, data, info) {
           if (err) throw err;
           assert.strictEqual(125, info.width);
           assert.strictEqual(200, info.height);
-          done();
+          fixtures.assertSimilar(fixtures.expected('extract.webp'), data, done);
         });
     });
   }
@@ -47,11 +47,12 @@ describe('Partial image extraction', function() {
   it('TIFF', function(done) {
     sharp(fixtures.inputTiff)
       .extract(63, 34, 341, 529)
-      .toFile(fixtures.path('output.extract.tiff'), function(err, info) {
+      .jpeg()
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(341, info.width);
         assert.strictEqual(529, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('extract.tiff'), data, done);
       });
   });
 
@@ -59,11 +60,11 @@ describe('Partial image extraction', function() {
     sharp(fixtures.inputJpg)
       .extract(10, 10, 10, 500, 500)
       .resize(100, 100)
-      .toFile(fixtures.path('output.extract.resize.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(100, info.width);
         assert.strictEqual(100, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('extract-resize.jpg'), data, done);
       });
   });
 
@@ -72,11 +73,11 @@ describe('Partial image extraction', function() {
       .resize(500, 500)
       .crop(sharp.gravity.north)
       .extract(10, 10, 100, 100)
-      .toFile(fixtures.path('output.resize.crop.extract.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(100, info.width);
         assert.strictEqual(100, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('resize-crop-extract.jpg'), data, done);
       });
   });
 
@@ -86,11 +87,11 @@ describe('Partial image extraction', function() {
       .resize(500, 500)
       .crop(sharp.gravity.north)
       .extract(10, 10, 100, 100)
-      .toFile(fixtures.path('output.extract.resize.crop.extract.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(100, info.width);
         assert.strictEqual(100, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('extract-resize-crop-extract.jpg'), data, done);
       });
   });
 
@@ -98,11 +99,11 @@ describe('Partial image extraction', function() {
     sharp(fixtures.inputJpg)
       .extract(10, 10, 100, 100)
       .rotate(90)
-      .toFile(fixtures.path('output.extract.extract-then-rotate.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(100, info.width);
         assert.strictEqual(100, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('extract-rotate.jpg'), data, done);
       });
   });
 
@@ -110,69 +111,44 @@ describe('Partial image extraction', function() {
     sharp(fixtures.inputJpg)
       .rotate(90)
       .extract(10, 10, 100, 100)
-      .toFile(fixtures.path('output.extract.rotate-then-extract.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(100, info.width);
         assert.strictEqual(100, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('rotate-extract.jpg'), data, done);
       });
   });
 
   describe('Invalid parameters', function() {
 
-    it('Undefined', function(done) {
-      var isValid = true;
-      try {
+    it('Undefined', function() {
+      assert.throws(function() {
         sharp(fixtures.inputJpg).extract();
-      } catch (err) {
-        isValid = false;
-      }
-      assert.strictEqual(false, isValid);
-      done();
+      });
     });
 
-    it('String top', function(done) {
-      var isValid = true;
-      try {
+    it('String top', function() {
+      assert.throws(function() {
         sharp(fixtures.inputJpg).extract('spoons', 10, 10, 10);
-      } catch (err) {
-        isValid = false;
-      }
-      assert.strictEqual(false, isValid);
-      done();
+      });
     });
 
-    it('Non-integral left', function(done) {
-      var isValid = true;
-      try {
+    it('Non-integral left', function() {
+      assert.throws(function() {
         sharp(fixtures.inputJpg).extract(10, 10.2, 10, 10);
-      } catch (err) {
-        isValid = false;
-      }
-      assert.strictEqual(false, isValid);
-      done();
+      });
     });
 
-    it('Negative width - negative', function(done) {
-      var isValid = true;
-      try {
+    it('Negative width - negative', function() {
+      assert.throws(function() {
         sharp(fixtures.inputJpg).extract(10, 10, -10, 10);
-      } catch (err) {
-        isValid = false;
-      }
-      assert.strictEqual(false, isValid);
-      done();
+      });
     });
 
-    it('Null height', function(done) {
-      var isValid = true;
-      try {
+    it('Null height', function() {
+      assert.throws(function() {
         sharp(fixtures.inputJpg).extract(10, 10, 10, null);
-      } catch (err) {
-        isValid = false;
-      }
-      assert.strictEqual(false, isValid);
-      done();
+      });
     });
 
   });

test/unit/rotate.js

@@ -37,12 +37,12 @@ describe('Rotation', function() {
     sharp(fixtures.inputJpgWithExif)
       .rotate()
       .resize(320)
-      .toFile(fixtures.path('output.exif.8.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(240, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('exif-8.jpg'), data, done);
       });
   });
 
@@ -50,12 +50,12 @@ describe('Rotation', function() {
     sharp(fixtures.inputJpgWithExifMirroring)
       .rotate()
       .resize(320)
-      .toFile(fixtures.path('output.exif.5.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(240, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('exif-5.jpg'), data, done);
       });
   });
 
@@ -85,26 +85,22 @@ describe('Rotation', function() {
       });
   });
 
-  it('Rotate to an invalid angle, should fail', function(done) {
-    var fail = false;
-    try {
+  it('Rotate to an invalid angle, should fail', function() {
+    assert.throws(function() {
       sharp(fixtures.inputJpg).rotate(1);
-      fail = true;
-    } catch (e) {}
-    assert(!fail);
-    done();
+    });
   });
 
   it('Flip - vertical', function(done) {
     sharp(fixtures.inputJpg)
       .resize(320)
       .flip()
-      .toFile(fixtures.path('output.flip.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(261, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('flip.jpg'), data, done);
       });
   });
 
@@ -112,12 +108,12 @@ describe('Rotation', function() {
     sharp(fixtures.inputJpg)
       .resize(320)
       .flop()
-      .toFile(fixtures.path('output.flop.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(261, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('flop.jpg'), data, done);
       });
   });
 
@@ -125,12 +121,12 @@ describe('Rotation', function() {
     sharp(fixtures.inputJpg)
       .resize(320)
       .flop()
-      .toFile(fixtures.path('output.flip.flop.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(261, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('flip-and-flop.jpg'), data, done);
       });
   });
 
@@ -139,12 +135,12 @@ describe('Rotation', function() {
       .resize(320)
       .flip(false)
       .flop(false)
-      .toFile(fixtures.path('output.flip.flop.nope.jpg'), function(err, info) {
+      .toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(261, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.inputJpg, data, done);
       });
   });