diff --git a/test/fixtures/expected/blur-0.3.jpg b/test/fixtures/expected/blur-0.3.jpg
new file mode 100644
index 00000000..e982f561
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diff --git a/test/fixtures/expected/blur-1.jpg b/test/fixtures/expected/blur-1.jpg
new file mode 100644
index 00000000..09112714
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diff --git a/test/fixtures/expected/blur-10.jpg b/test/fixtures/expected/blur-10.jpg
new file mode 100644
index 00000000..9e0945cf
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diff --git a/test/fixtures/expected/blur-mild.jpg b/test/fixtures/expected/blur-mild.jpg
new file mode 100644
index 00000000..383f05ed
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diff --git a/test/fixtures/expected/sharpen-10.jpg b/test/fixtures/expected/sharpen-10.jpg
new file mode 100644
index 00000000..f04e7e9b
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diff --git a/test/fixtures/expected/sharpen-3-0.5-2.5.jpg b/test/fixtures/expected/sharpen-3-0.5-2.5.jpg
new file mode 100644
index 00000000..5901f668
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diff --git a/test/fixtures/expected/sharpen-5-2-4.jpg b/test/fixtures/expected/sharpen-5-2-4.jpg
new file mode 100644
index 00000000..df1da7ba
Binary files /dev/null and b/test/fixtures/expected/sharpen-5-2-4.jpg differ
diff --git a/test/fixtures/expected/sharpen-mild.jpg b/test/fixtures/expected/sharpen-mild.jpg
new file mode 100644
index 00000000..86b9424c
Binary files /dev/null and b/test/fixtures/expected/sharpen-mild.jpg differ
diff --git a/test/unit/blur.js b/test/unit/blur.js
index 5c6c080f..15f50404 100755
--- a/test/unit/blur.js
+++ b/test/unit/blur.js
@@ -13,12 +13,11 @@ describe('Blur', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 240)
       .blur(1)
-      .toFile(fixtures.path('output.blur-1.jpg'), function(err, info) {
-        if (err) throw err;
+      .toBuffer(function(err, data, info) {
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(240, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('blur-1.jpg'), data, done);
       });
   });
 
@@ -26,12 +25,11 @@ describe('Blur', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 240)
       .blur(10)
-      .toFile(fixtures.path('output.blur-10.jpg'), function(err, info) {
-        if (err) throw err;
+      .toBuffer(function(err, data, info) {
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(240, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('blur-10.jpg'), data, done);
       });
   });
 
@@ -39,12 +37,11 @@ describe('Blur', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 240)
       .blur(0.3)
-      .toFile(fixtures.path('output.blur-0.3.jpg'), function(err, info) {
-        if (err) throw err;
+      .toBuffer(function(err, data, info) {
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(240, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('blur-0.3.jpg'), data, done);
       });
   });
 
@@ -52,24 +49,18 @@ describe('Blur', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 240)
       .blur()
-      .toFile(fixtures.path('output.blur-mild.jpg'), function(err, info) {
-        if (err) throw err;
+      .toBuffer(function(err, data, info) {
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(240, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('blur-mild.jpg'), data, done);
       });
   });
 
-  it('invalid radius', function(done) {
-    var isValid = true;
-    try {
+  it('invalid radius', function() {
+    assert.throws(function() {
       sharp(fixtures.inputJpg).blur(0.1);
-    } catch (err) {
-      isValid = false;
-    }
-    assert.strictEqual(false, isValid);
-    done();
+    });
   });
 
   it('blurred image is smaller than non-blurred', function(done) {
@@ -77,7 +68,6 @@ describe('Blur', function() {
       .resize(320, 240)
       .blur(false)
       .toBuffer(function(err, notBlurred, info) {
-        if (err) throw err;
         assert.strictEqual(true, notBlurred.length > 0);
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
@@ -86,7 +76,6 @@ describe('Blur', function() {
           .resize(320, 240)
           .blur(true)
           .toBuffer(function(err, blurred, info) {
-            if (err) throw err;
             assert.strictEqual(true, blurred.length > 0);
             assert.strictEqual(true, blurred.length < notBlurred.length);
             assert.strictEqual('jpeg', info.format);
diff --git a/test/unit/sharpen.js b/test/unit/sharpen.js
index 96bf024f..c989b901 100755
--- a/test/unit/sharpen.js
+++ b/test/unit/sharpen.js
@@ -13,12 +13,11 @@ describe('Sharpen', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 240)
       .sharpen(10)
-      .toFile(fixtures.path('output.sharpen-10.jpg'), function(err, info) {
-        if (err) throw err;
+      .toBuffer(function(err, data, info) {
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(240, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('sharpen-10.jpg'), data, done);
       });
   });
 
@@ -26,12 +25,11 @@ describe('Sharpen', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 240)
       .sharpen(3, 0.5, 2.5)
-      .toFile(fixtures.path('output.sharpen-3-0.5-2.5.jpg'), function(err, info) {
-        if (err) throw err;
+      .toBuffer(function(err, data, info) {
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(240, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('sharpen-3-0.5-2.5.jpg'), data, done);
       });
   });
 
@@ -39,12 +37,11 @@ describe('Sharpen', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 240)
       .sharpen(5, 2, 4)
-      .toFile(fixtures.path('output.sharpen-5-2-4.jpg'), function(err, info) {
-        if (err) throw err;
+      .toBuffer(function(err, data, info) {
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(240, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('sharpen-5-2-4.jpg'), data, done);
       });
   });
 
@@ -52,46 +49,30 @@ describe('Sharpen', function() {
     sharp(fixtures.inputJpg)
       .resize(320, 240)
       .sharpen()
-      .toFile(fixtures.path('output.sharpen-mild.jpg'), function(err, info) {
-        if (err) throw err;
+      .toBuffer(function(err, data, info) {
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
         assert.strictEqual(240, info.height);
-        done();
+        fixtures.assertSimilar(fixtures.expected('sharpen-mild.jpg'), data, done);
       });
   });
 
-  it('invalid radius', function(done) {
-    var isValid = true;
-    try {
+  it('invalid radius', function() {
+    assert.throws(function() {
       sharp(fixtures.inputJpg).sharpen(1.5);
-    } catch (err) {
-      isValid = false;
-    }
-    assert.strictEqual(false, isValid);
-    done();
+    });
   });
 
-  it('invalid flat', function(done) {
-    var isValid = true;
-    try {
+  it('invalid flat', function() {
+    assert.throws(function() {
       sharp(fixtures.inputJpg).sharpen(1, -1);
-    } catch (err) {
-      isValid = false;
-    }
-    assert.strictEqual(false, isValid);
-    done();
+    });
   });
 
-  it('invalid jagged', function(done) {
-    var isValid = true;
-    try {
+  it('invalid jagged', function() {
+    assert.throws(function() {
       sharp(fixtures.inputJpg).sharpen(1, 1, -1);
-    } catch (err) {
-      isValid = false;
-    }
-    assert.strictEqual(false, isValid);
-    done();
+    });
   });
 
   it('sharpened image is larger than non-sharpened', function(done) {
@@ -99,7 +80,6 @@ describe('Sharpen', function() {
       .resize(320, 240)
       .sharpen(false)
       .toBuffer(function(err, notSharpened, info) {
-        if (err) throw err;
         assert.strictEqual(true, notSharpened.length > 0);
         assert.strictEqual('jpeg', info.format);
         assert.strictEqual(320, info.width);
@@ -108,7 +88,6 @@ describe('Sharpen', function() {
           .resize(320, 240)
           .sharpen(true)
           .toBuffer(function(err, sharpened, info) {
-            if (err) throw err;
             assert.strictEqual(true, sharpened.length > 0);
             assert.strictEqual(true, sharpened.length > notSharpened.length);
             assert.strictEqual('jpeg', info.format);