Tests for GimpGradientFile and a sample .ggr by me

Tests/images/gimp_gradient.ggr

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+GIMP Gradient
+4
+0.000000 0.351923 0.534893 1.000000 1.000000 1.000000 0.910000 0.730303 0.510606 1.000000 0.480000 1 0
+0.501504 0.611002 0.637730 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 1.000000 1 0
+0.931891 0.951264 1.000000 0.531255 0.316078 1.031173 1.000000 0.000000 0.000000 0.000000 1.000000 0 0
+0.810551 0.881217 0.921883 0.717576 0.441331 0.081217 1.000000 0.751576 0.410331 0.081217 1.000000 0 0

Tests/test_file_gimpgradient.py

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+from helper import unittest, PillowTestCase
+
+from PIL import GimpGradientFile
+
+TEST_FILE = "Tests/images/gimp_gradient.ggr"
+
+
+class TestImage(PillowTestCase):
+
+    def test_linear_pos_le_middle(self):
+        # Arrange
+        middle = 0.5
+        pos = 0.25
+
+        # Act
+        ret = GimpGradientFile.linear(middle, pos)
+
+        # Assert
+        self.assertEqual(ret, 0.25)
+
+    def test_linear_pos_le_small_middle(self):
+        # Arrange
+        middle = 1e-11
+        pos = 1e-12
+
+        # Act
+        ret = GimpGradientFile.linear(middle, pos)
+
+        # Assert
+        self.assertEqual(ret, 0.0)
+
+    def test_linear_pos_gt_middle(self):
+        # Arrange
+        middle = 0.5
+        pos = 0.75
+
+        # Act
+        ret = GimpGradientFile.linear(middle, pos)
+
+        # Assert
+        self.assertEqual(ret, 0.75)
+
+    def test_linear_pos_gt_small_middle(self):
+        # Arrange
+        middle = 1 - 1e-11
+        pos = 1 - 1e-12
+
+        # Act
+        ret = GimpGradientFile.linear(middle, pos)
+
+        # Assert
+        self.assertEqual(ret, 1.0)
+
+    def test_curved(self):
+        # Arrange
+        middle = 0.5
+        pos = 0.75
+
+        # Act
+        ret = GimpGradientFile.curved(middle, pos)
+
+        # Assert
+        self.assertEqual(ret, 0.75)
+
+    def test_sphere_increasing(self):
+        # Arrange
+        middle = 0.5
+        pos = 0.75
+
+        # Act
+        ret = GimpGradientFile.sphere_increasing(middle, pos)
+
+        # Assert
+        self.assertEqual(ret, 0.9682458365518543)
+
+    def test_sphere_decreasing(self):
+        # Arrange
+        middle = 0.5
+        pos = 0.75
+
+        # Act
+        ret = GimpGradientFile.sphere_decreasing(middle, pos)
+
+        # Assert
+        self.assertEqual(ret, 0.3385621722338523)
+
+    def test_load_via_imagepalette(self):
+        # Arrange
+        from PIL import ImagePalette
+
+        # Act
+        palette = ImagePalette.load(TEST_FILE)
+
+        # Assert
+        # load returns raw palette information
+        self.assertEqual(len(palette[0]), 1024)
+        self.assertEqual(palette[1], "RGBA")
+
+
+if __name__ == '__main__':
+    unittest.main()
+
+# End of file