added test for compare

test/compare.js

@@ -7,26 +7,32 @@ module.exports = function (gm, dir, finish, GM) {
     if (err) return finish(err);
     if (!same) return finish(new Error('Compare should be the same!'));
 
-    // Create a new noisy image
-    gm.noise(0.3).write(dir + '/noise3.png', function (err) {
+    // Compare almost similar images for which ImageMagick
+    // returns a exponent-style floating point number
+    gm.compare(__dirname + '/fixtures/compare_1.png', __dirname + '/fixtures/compare_2.png', function(err, same, diff) {
       if (err) return finish(err);
 
-      var options = {
-        highlightColor: 'yellow',
-        file: dir + '/diff.png',
-        tolerance: 0.001
-      };
-
-      // Compare these images and write diff to a file.
-      GM.compare(dir + '/original.jpg', dir + '/noise3.png', options, function(err, same) {
+      // Create a new noisy image
+      gm.noise(0.3).write(dir + '/noise3.png', function (err) {
         if (err) return finish(err);
         if (!same) return finish(new Error('Compare should be the same!'));
 
-        fs.exists(options.file, function(exists) {
-          if (exists) finish();
-          else finish(new Error('Diff file does not exist.'));
+        var options = {
+          highlightColor: 'yellow',
+          file: dir + '/diff.png',
+          tolerance: 0.001
+        };
+
+        // Compare these images and write to a file.
+        GM.compare(dir + '/original.jpg', dir + '/noise3.png', options, function(err) {
+          if (err) return finish(err);
+
+          fs.exists(options.file, function(exists) {
+            if (exists) finish();
+            else finish(new Error('Diff file does not exist.'));
+          });
         });
       });
-    })
+    });
   });
 };