Add more tests to test_stream. (#616)

* Define constants in `test_stream`.

* Add `Test_RemoteSeek` to `test_stream`.

* Add `Test_SetSize` to `test_stream`.
See also:
https://learn.microsoft.com/en-us/windows/win32/api/shlwapi/nf-shlwapi-istream_size

* Add `Test_RemoteCopyTo` to `test_stream`.

* Add `Test_Clone` to `test_stream`.

comtypes/test/test_stream.py

@@ -1,13 +1,19 @@
 import unittest as ut
 
-from ctypes import POINTER, byref, c_bool, c_ubyte
+from ctypes import POINTER, byref, c_bool, c_ubyte, c_ulonglong, oledll, pointer
 import comtypes
 import comtypes.client
 
 comtypes.client.GetModule("portabledeviceapi.dll")
 from comtypes.gen.PortableDeviceApiLib import IStream
 
 
+STGC_DEFAULT = 0
+STREAM_SEEK_SET = 0
+STREAM_SEEK_CUR = 1
+STREAM_SEEK_END = 2
+
+
 def _create_stream() -> IStream:
     # Create an IStream
     stream = POINTER(IStream)()  # type: ignore
@@ -35,9 +41,8 @@ def test_RemoteRead(self):
         stream.RemoteWrite(pv, len(test_data))
 
         # Make sure the data actually gets written before trying to read back
-        stream.Commit(0)
+        stream.Commit(STGC_DEFAULT)
         # Move the stream back to the beginning
-        STREAM_SEEK_SET = 0
         stream.RemoteSeek(0, STREAM_SEEK_SET)
 
         buffer_size = 1024
@@ -49,5 +54,78 @@ def test_RemoteRead(self):
         self.assertEqual(bytearray(read_buffer)[0:data_read], test_data)
 
 
+class Test_RemoteSeek(ut.TestCase):
+    def _create_sample_stream(self) -> IStream:
+        stream = _create_stream()
+        test_data = b"spam egg bacon ham"
+        pv = (c_ubyte * len(test_data)).from_buffer(bytearray(test_data))
+        stream.RemoteWrite(pv, len(test_data))
+        stream.Commit(STGC_DEFAULT)
+        return stream
+
+    def test_takes_STREAM_SEEK_SET_as_origin(self):
+        stream = self._create_sample_stream()
+        newpos = stream.RemoteSeek(9, STREAM_SEEK_SET)
+        self.assertEqual(newpos, 9)
+        buf, read = stream.RemoteRead(1024)
+        self.assertEqual(bytearray(buf)[0:read], b"bacon ham")
+
+    def test_takes_STREAM_SEEK_CUR_as_origin(self):
+        stream = self._create_sample_stream()
+        stream.RemoteSeek(8, STREAM_SEEK_SET)
+        newpos = stream.RemoteSeek(7, STREAM_SEEK_CUR)
+        self.assertEqual(newpos, 15)
+        buf, read = stream.RemoteRead(1024)
+        self.assertEqual(bytearray(buf)[0:read], b"ham")
+
+    def test_takes_STREAM_SEEK_END_as_origin(self):
+        stream = self._create_sample_stream()
+        stream.RemoteSeek(8, STREAM_SEEK_SET)
+        newpos = stream.RemoteSeek(-13, STREAM_SEEK_END)
+        self.assertEqual(newpos, 5)
+        buf, read = stream.RemoteRead(1024)
+        self.assertEqual(bytearray(buf)[0:read], b"egg bacon ham")
+
+
+class Test_SetSize(ut.TestCase):
+    def test_SetSize(self):
+        stream = _create_stream()
+        stream.SetSize(42)
+        pui = pointer(c_ulonglong())
+        oledll.shlwapi.IStream_Size(stream, pui)
+        self.assertEqual(pui.contents.value, 42)
+
+
+class Test_RemoteCopyTo(ut.TestCase):
+    def test_RemoteCopyTo(self):
+        src = _create_stream()
+        dst = _create_stream()
+        test_data = b"parrot"
+        pv = (c_ubyte * len(test_data)).from_buffer(bytearray(test_data))
+        src_written = src.RemoteWrite(pv, len(test_data))
+        src.Commit(STGC_DEFAULT)
+        src.RemoteSeek(0, STREAM_SEEK_SET)
+        cpy_read, cpy_written = src.RemoteCopyTo(dst, src_written)
+        self.assertEqual(cpy_read, len(test_data))
+        self.assertEqual(cpy_written, len(test_data))
+        dst.Commit(STGC_DEFAULT)
+        dst.RemoteSeek(0, STREAM_SEEK_SET)
+        dst_buf, dst_read = dst.RemoteRead(1024)
+        self.assertEqual(bytearray(dst_buf)[0:dst_read], test_data)
+
+
+class Test_Clone(ut.TestCase):
+    def test_Clone(self):
+        orig = _create_stream()
+        test_data = b"spam egg bacon ham"
+        pv = (c_ubyte * len(test_data)).from_buffer(bytearray(test_data))
+        orig.RemoteWrite(pv, len(test_data))
+        orig.Commit(STGC_DEFAULT)
+        orig.RemoteSeek(0, STREAM_SEEK_SET)
+        new_stm = orig.Clone()
+        buf, read = new_stm.RemoteRead(1024)
+        self.assertEqual(bytearray(buf)[0:read], test_data)
+
+
 if __name__ == "__main__":
     ut.main()