Add simple tests (run ./pytest).

test_everything.py

@@ -0,0 +1,13 @@
+from ResDecompress import GetEncoding, DecompressResource, CompressResource
+
+def compress_then_extract(dat, encoding):
+    a = CompressResource(dat, encoding);
+    if encoding != 'UnknownCompression': assert a.startswith(b'\xA8\x9F\x65\x72')
+    assert GetEncoding(a) == encoding
+    b = DecompressResource(a)
+    assert b == dat
+
+def test_all():
+    for enc in ['GreggyBits', 'UnknownCompression']:
+        compress_then_extract(bytes(100), encoding=enc)
+        compress_then_extract(b'The quick brown fox jumps over the lazy dog', encoding=enc)