From 07241cd37a732e4219257e6b2fc67a84085b37f6 Mon Sep 17 00:00:00 2001
From: Paul Sokolovsky
Date: Mon, 5 Jun 2017 23:54:21 +0300
Subject: py/objstringio: If created from immutable object, follow copy on
 write policy.

Don't create copy of immutable object's contents until .write() is called
on BytesIO.
---
 tests/micropython/heapalloc_bytesio2.py     | 20 ++++++++++++++++++++
 tests/micropython/heapalloc_bytesio2.py.exp |  1 +
 2 files changed, 21 insertions(+)
 create mode 100644 tests/micropython/heapalloc_bytesio2.py
 create mode 100644 tests/micropython/heapalloc_bytesio2.py.exp

(limited to 'tests/micropython')

diff --git a/tests/micropython/heapalloc_bytesio2.py b/tests/micropython/heapalloc_bytesio2.py
new file mode 100644
index 000000000..cd76f5807
--- /dev/null
+++ b/tests/micropython/heapalloc_bytesio2.py
@@ -0,0 +1,20 @@
+# Creating BytesIO from immutable object should not immediately
+# copy its content.
+try:
+    import uio
+    import micropython
+    micropython.mem_total
+except (ImportError, AttributeError):
+    print("SKIP")
+    raise SystemExit
+
+
+data = b"1234" * 256
+
+before = micropython.mem_total()
+
+buf = uio.BytesIO(data)
+
+after = micropython.mem_total()
+
+print(after - before < len(data))
diff --git a/tests/micropython/heapalloc_bytesio2.py.exp b/tests/micropython/heapalloc_bytesio2.py.exp
new file mode 100644
index 000000000..0ca95142b
--- /dev/null
+++ b/tests/micropython/heapalloc_bytesio2.py.exp
@@ -0,0 +1 @@
+True
-- 
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