From 67c1258cfcb9dc23b000c0fe572da59f0cf76217 Mon Sep 17 00:00:00 2001
From: Luis G <luis.gg1990@gmail.com>
Date: Sun, 19 Jun 2016 21:39:31 -0300
Subject: [PATCH 1/4] Expose registered file extensions

This adds a new method in Image (registered_extensions) that exposes the
internal EXTENSION dictionary to consumers of the library
---
 PIL/Image.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/PIL/Image.py b/PIL/Image.py
index f49834e5b47..e368ef18779 100644
--- a/PIL/Image.py
+++ b/PIL/Image.py
@@ -2512,6 +2512,16 @@ def register_extension(id, extension):
     EXTENSION[extension.lower()] = id.upper()
 
 
+def registered_extensions():
+    """
+    Returns a dictionary containing all file extensions belonging
+    to registered plugins
+    """
+    if not bool(EXTENSION):
+        init()
+    return EXTENSION
+
+
 # --------------------------------------------------------------------
 # Simple display support.  User code may override this.
 

From dad59715618926a405eff12c828b2c704053ff18 Mon Sep 17 00:00:00 2001
From: Luis G <luis.gg1990@gmail.com>
Date: Mon, 20 Jun 2016 12:36:26 -0300
Subject: [PATCH 2/4] Add unit tests

Add unit tests for registered_extensions
---
 Tests/test_image.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Tests/test_image.py b/Tests/test_image.py
index f1457a85bb6..85d1f3f5c37 100644
--- a/Tests/test_image.py
+++ b/Tests/test_image.py
@@ -196,6 +196,24 @@ def test_alpha_composite(self):
         img_colors = sorted(img.getcolors())
         self.assertEqual(img_colors, expected_colors)
 
+    def test_registered_extensions_uninitialized(self):
+        # Act
+        ext = Image.registered_extensions()
+
+        # Assert
+        self.assertEqual(bool(ext), True)
+
+    def test_registered_extensions(self):
+        # Arrange
+        # Open an image to trigger plugin registration
+        Image.open('Tests/images/rgb.jpg')
+
+        # Act
+        ext = Image.registered_extensions()
+
+        # Assert
+        self.assertEqual(bool(ext), True)
+
     def test_effect_mandelbrot(self):
         # Arrange
         size = (512, 512)

From 2a93cdb698fea78a3fec9b3bace5244178db1360 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@gmail.com>
Date: Sat, 7 Jan 2017 11:35:09 +1100
Subject: [PATCH 3/4] Simplified assertEqual checks to assertTrue

---
 Tests/test_image.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Tests/test_image.py b/Tests/test_image.py
index 85d1f3f5c37..a02596b2072 100644
--- a/Tests/test_image.py
+++ b/Tests/test_image.py
@@ -201,7 +201,7 @@ def test_registered_extensions_uninitialized(self):
         ext = Image.registered_extensions()
 
         # Assert
-        self.assertEqual(bool(ext), True)
+        self.assertTrue(bool(ext))
 
     def test_registered_extensions(self):
         # Arrange
@@ -212,7 +212,7 @@ def test_registered_extensions(self):
         ext = Image.registered_extensions()
 
         # Assert
-        self.assertEqual(bool(ext), True)
+        self.assertTrue(bool(ext))
 
     def test_effect_mandelbrot(self):
         # Arrange

From 89742225bfade3df3f7cc2d755916c75ff7aad3c Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@gmail.com>
Date: Sat, 7 Jan 2017 13:20:16 +1100
Subject: [PATCH 4/4] Fixed test coverage

---
 Tests/test_image.py | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/Tests/test_image.py b/Tests/test_image.py
index a02596b2072..70bc638773c 100644
--- a/Tests/test_image.py
+++ b/Tests/test_image.py
@@ -197,11 +197,20 @@ def test_alpha_composite(self):
         self.assertEqual(img_colors, expected_colors)
 
     def test_registered_extensions_uninitialized(self):
+        # Arrange
+        Image._initialized = 0
+        extension = Image.EXTENSION
+        Image.EXTENSION = {}
+
         # Act
-        ext = Image.registered_extensions()
+        Image.registered_extensions()
 
         # Assert
-        self.assertTrue(bool(ext))
+        self.assertEqual(Image._initialized, 2)
+
+        # Restore the original state and assert
+        Image.EXTENSION = extension
+        self.assertTrue(Image.EXTENSION)
 
     def test_registered_extensions(self):
         # Arrange
@@ -209,10 +218,12 @@ def test_registered_extensions(self):
         Image.open('Tests/images/rgb.jpg')
 
         # Act
-        ext = Image.registered_extensions()
+        extensions = Image.registered_extensions()
 
         # Assert
-        self.assertTrue(bool(ext))
+        self.assertTrue(bool(extensions))
+        for ext in ['.cur', '.icns', '.tif', '.tiff']:
+            self.assertIn(ext, extensions)
 
     def test_effect_mandelbrot(self):
         # Arrange