Added support for decoding plain PPM formats

Tests/test_file_ppm.py

@@ -3,7 +3,7 @@
 
 import pytest
 
-from PIL import Image, UnidentifiedImageError
+from PIL import Image, PpmImagePlugin
 
 from .helper import assert_image_equal_tofile, assert_image_similar, hopper
 
@@ -50,20 +50,144 @@ def test_pnm(tmp_path):
         assert_image_equal_tofile(im, f)
 
 
-def test_magic(tmp_path):
+def test_plain_pbm(tmp_path):
+    with Image.open("Tests/images/hopper_1bit_plain.pbm") as im:
+        assert_image_equal_tofile(im, "Tests/images/hopper_1bit.pbm")
+
+
+def test_8bit_plain_pgm(tmp_path):
+    with Image.open("Tests/images/hopper_8bit_plain.pgm") as im:
+        assert_image_equal_tofile(im, "Tests/images/hopper_8bit.pgm")
+
+
+def test_8bit_plain_ppm(tmp_path):
+    with Image.open("Tests/images/hopper_8bit_plain.ppm") as im:
+        assert_image_equal_tofile(im, "Tests/images/hopper_8bit.ppm")
+
+
+def test_16bit_plain_pgm(tmp_path):
+    with Image.open("Tests/images/hopper_16bit_plain.pgm") as im:
+        assert im.mode == "I"
+        assert im.size == (128, 128)
+        assert im.get_format_mimetype() == "image/x-portable-graymap"
+
+        assert_image_equal_tofile(im, "Tests/images/hopper_16bit.pgm")
+
+
+def test_32bit_plain_pgm(tmp_path):
+    with Image.open("Tests/images/hopper_32bit_plain.pgm") as im:
+        assert im.mode == "I"
+        assert im.size == (128, 128)
+        assert im.get_format_mimetype() == "image/x-portable-graymap"
+
+        assert_image_equal_tofile(im, "Tests/images/hopper_32bit.pgm")
+
+
+def test_plain_pbm_data_with_comments(tmp_path):
+    path1 = str(tmp_path / "temp1.ppm")
+    path2 = str(tmp_path / "temp2.ppm")
+    comment = b"# veeery long comment" * 10**6
+    with open(path1, "wb") as f1, open(path2, "wb") as f2:
+        f1.write(b"P1\n2 2\n\n1010")
+        f2.write(b"P1\n2 2\n" + comment + b"\n1010" + comment)
+
+    with Image.open(path1) as im:
+        assert_image_equal_tofile(im, path2)
+
+
+def test_plain_pbm_truncated_data(tmp_path):
     path = str(tmp_path / "temp.ppm")
     with open(path, "wb") as f:
-        f.write(b"PyInvalid")
+        f.write(b"P1\n128 128\n")
 
-    with pytest.raises(UnidentifiedImageError):
-        with Image.open(path):
-            pass
+    with Image.open(path) as im:
+        with pytest.raises(ValueError):
+            im.load()
+
+
+def test_plain_pbm_invalid_data(tmp_path):
+    path = str(tmp_path / "temp.ppm")
+    with open(path, "wb") as f:
+        f.write(b"P1\n128 128\n1009")
+
+    with Image.open(path) as im:
+        with pytest.raises(ValueError):
+            im.load()
+
+
+def test_plain_ppm_data_with_comments(tmp_path):
+    path1 = str(tmp_path / "temp1.ppm")
+    path2 = str(tmp_path / "temp2.ppm")
+    comment = b"# veeery long comment" * 10**6
+    with open(path1, "wb") as f1, open(path2, "wb") as f2:
+        f1.write(b"P3\n2 2\n255\n0 0 0 001 1 1 2 2 2 255 255 255")
+        f2.write(
+            b"P3\n2 2\n255\n" + comment + b"\n0 0 0 001 1 1 2 2 2 255 255 255" + comment
+        )
+
+    with Image.open(path1) as im:
+        assert_image_equal_tofile(im, path2)
+
+
+def test_plain_ppm_truncated_data(tmp_path):
+    path = str(tmp_path / "temp.ppm")
+    with open(path, "wb") as f:
+        f.write(b"P3\n128 128\n255\n")
+
+    with Image.open(path) as im:
+        with pytest.raises(ValueError):
+            im.load()
+
+
+def test_plain_ppm_invalid_data(tmp_path):
+    path = str(tmp_path / "temp.ppm")
+    with open(path, "wb") as f:
+        f.write(b"P3\n128 128\n255\n100A")
+
+    with Image.open(path) as im:
+        with pytest.raises(ValueError):
+            im.load()
+
+
+def test_plain_ppm_half_token_too_long(tmp_path):
+    path = str(tmp_path / "temp.ppm")
+    with open(path, "wb") as f:
+        f.write(b"P3\n128 128\n255\n012345678910")
+
+    with Image.open(path) as im:
+        with pytest.raises(ValueError):
+            im.load()
+
+
+def test_plain_ppm_token_too_long(tmp_path):
+    path = str(tmp_path / "temp.ppm")
+    with open(path, "wb") as f:
+        f.write(b"P3\n128 128\n255\n012345678910 0")
+
+    with Image.open(path) as im:
+        with pytest.raises(ValueError):
+            im.load()
+
+
+def test_plain_ppm_value_too_large(tmp_path):
+    path = str(tmp_path / "temp.ppm")
+    with open(path, "wb") as f:
+        f.write(b"P3\n128 128\n255\n256")
+
+    with Image.open(path) as im:
+        with pytest.raises(ValueError):
+            im.load()
+
+
+def test_magic(tmp_path):
+    with pytest.raises(SyntaxError):
+        PpmImagePlugin.PpmImageFile(fp=BytesIO(b"PyInvalid"))
 
 
 def test_header_with_comments(tmp_path):
     path = str(tmp_path / "temp.ppm")
     with open(path, "wb") as f:
-        f.write(b"P6 #comment\n#comment\r12#comment\r8\n128 #comment\n255\n")
+        f.write(b"P6 #comment\n#comment\r 12#comment\r8\n128 #comment\n255\n")
 
     with Image.open(path) as im:
         assert im.size == (128, 128)
@@ -79,7 +203,7 @@ def test_non_integer_token(tmp_path):
             pass
 
 
-def test_token_too_long(tmp_path):
+def test_header_token_too_long(tmp_path):
     path = str(tmp_path / "temp.ppm")
     with open(path, "wb") as f:
         f.write(b"P6\n 01234567890")
@@ -103,7 +227,7 @@ def test_too_many_colors(tmp_path):
     assert str(e.value) == "Too many colors for band: 1000"
 
 
-def test_truncated_file(tmp_path):
+def test_truncated_header(tmp_path):
     path = str(tmp_path / "temp.pgm")
     with open(path, "w") as f:
         f.write("P6")