Add test for unused data

Author: rhpvorderman

tests/test_isal_zlib.py

@@ -0,0 +1,55 @@
+# Copyright (c) 2020 Leiden University Medical Center
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+from isal import isal_zlib
+
+import pytest
+
+
+@pytest.mark.parametrize("wbits", [-15, 15, 31])
+def test_decompress_unused_data(wbits):
+    """
+    Test from CPython's zlib test suite, now improved for all possible modes
+    raw deflate, zlib and gzip
+    :return:
+    """
+    source = b'abcdefghijklmnopqrstuvwxyz'
+    remainder = b'0123456789'
+    y = isal_zlib.compress(source, wbits=wbits)
+    x = y + remainder
+
+    for maxlen in 0, 1000:
+        for step in 1, 2, len(y), len(x):
+            dco = isal_zlib.decompressobj(wbits=wbits)
+            data = b''
+            for i in range(0, len(x), step):
+                if i < len(y):
+                    assert dco.unused_data == b''
+                if maxlen == 0:
+                    data += dco.decompress(x[i: i + step])
+                    assert dco.unconsumed_tail == b''
+                else:
+                    data += dco.decompress(
+                        dco.unconsumed_tail + x[i: i + step], maxlen)
+            data += dco.flush()
+            assert dco.eof
+            assert data == source
+            assert dco.unconsumed_tail == b''
+            assert dco.unused_data == remainder