Index: source/lib/allocators/tests/test_uniquerange.h
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--- /dev/null
+++ source/lib/allocators/tests/test_uniquerange.h
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+/* Copyright (C) 2020 Wildfire Games.
+ *
+ * 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.
+ */
+
+#include "lib/self_test.h"
+
+#include "lib/file/io/io.h"
+
+class TestUniqueRange : public CxxTest::TestSuite
+{
+public:
+	void test_BufferObtained()
+	{
+		// During development of D1511, the assertion
+		// ASSERT(idxDeleter < numDeleters); got tripped in
+		// CallUniqueRangeDeleter/2, but only on the macos
+		// build slave. gdb revealed the only place in the test
+		// suite running through that method was
+		// ArchiveReader_Zip::LocateCentralDirectory/5, so this
+		// test case extracts the sole UniqueRange access to "bring
+		// it on the examination table".
+		const size_t maxScanSize = 66000u;
+		io::BufferPtr buf(io::Allocate(maxScanSize));
+
+		TS_ASSERT(nullptr != buf.get());
+		// As buf goes out of scope, it should auto-release the
+		// memory reserved via io::Allocate/1.
+	}
+};