Merge pull request #787 from palaviv/os-fd

Add os.{read,write,remove,unlink}

tests/snippets/stdlib_os.py

@@ -2,7 +2,36 @@ import os
 
 from testutils import assert_raises
 
-assert os.open('README.md', 0) > 0
+fd = os.open('README.md', 0)
+assert fd > 0
+
+os.close(fd)
+assert_raises(OSError, lambda: os.read(fd, 10))
+
+FNAME = "test_file_that_no_one_will_have_on_disk"
+CONTENT = b"testing"
+CONTENT2 = b"rustpython"
+CONTENT3 = b"BOYA"
+
+class TestWithFile():
+	def __enter__(self):
+		open(FNAME, "wb")
+		return FNAME
+
+	def __exit__(self, exc_type, exc_val, exc_tb):
+		os.remove(FNAME)
+
+
+with TestWithFile() as fname:
+	fd = os.open(fname, 1)
+	assert os.write(fd, CONTENT2) == len(CONTENT2)
+	assert os.write(fd, CONTENT3) == len(CONTENT3)
+	os.close(fd)
+
+	fd = os.open(fname, 0)
+	assert os.read(fd, len(CONTENT2)) == CONTENT2
+	assert os.read(fd, len(CONTENT3)) == CONTENT3
+	os.close(fd)
 
 
 assert_raises(FileNotFoundError, lambda: os.open('DOES_NOT_EXIST', 0))