libio: add a simple unit test for the memory istream_t implementation

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

2 files changed, 83 insertions, 1 deletions

diff --git a/lib/io/Makemodule.am b/lib/io/Makemodule.am
index 7427b42..5ec1f7e 100644
--- a/lib/io/Makemodule.am
+++ b/lib/io/Makemodule.am
@@ -19,10 +19,14 @@ endif
 
 noinst_LIBRARIES += libio.a
 
-LIBIO_TESTS = test_get_line test_sparse_fb test_istream_read \
+LIBIO_TESTS = test_istream_mem test_get_line test_sparse_fb test_istream_read \
 	test_istream_skip test_stream_splice test_dir_iterator \
 	test_dir_tree_iterator test_dir_tree_iterator2 test_dir_tree_iterator3
 
+test_istream_mem_SOURCES = lib/io/test/istream_mem.c
+test_istream_mem_LDADD = libio.a libcompat.a
+test_istream_mem_CPPFLAGS = $(AM_CPPFLAGS)
+
 test_get_line_SOURCES = lib/io/test/get_line.c
 test_get_line_LDADD = libio.a libcompat.a
 test_get_line_CPPFLAGS = $(AM_CPPFLAGS)
diff --git a/lib/io/test/istream_mem.c b/lib/io/test/istream_mem.c
new file mode 100644
index 0000000..c74b1f5
--- /dev/null
+++ b/lib/io/test/istream_mem.c
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * istream_mem.c
+ *
+ * Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "util/test.h"
+#include "io/mem.h"
+
+static const size_t end0 = 449;	/* region 1: filled with 'A' */
+static const size_t end1 = 521;	/* region 2: filled with 'B' */
+static const size_t end2 = 941;	/* region 3: filled with 'C' */
+
+static unsigned char data[941];
+
+static unsigned char byte_at_offset(size_t off)
+{
+	if (off < end0)
+		return 'A';
+	if (off < end1)
+		return 'B';
+	return 'C';
+}
+
+static void init_buffer(void)
+{
+	for (size_t i = 0; i < end2; ++i)
+		data[i] = byte_at_offset(i);
+}
+
+int main(int argc, char **argv)
+{
+	bool eat_all = true;
+	size_t i, diff;
+	istream_t *in;
+	int ret;
+	(void)argc; (void)argv;
+
+	init_buffer();
+
+	in = istream_memory_create("memstream.txt", 61, data, sizeof(data));
+	TEST_NOT_NULL(in);
+	TEST_EQUAL_UI(((sqfs_object_t *)in)->refcount, 1);
+
+	TEST_STR_EQUAL(istream_get_filename(in), "memstream.txt");
+	TEST_NOT_NULL(in->buffer);
+	TEST_EQUAL_UI(in->buffer_used, 0);
+
+	for (i = 0; i < end2; i += diff) {
+		ret = istream_precache(in);
+		TEST_EQUAL_I(ret, 0);
+
+		if ((end2 - i) >= 61) {
+			TEST_NOT_NULL(in->buffer);
+			TEST_EQUAL_UI(in->buffer_used, 61);
+		} else {
+			TEST_NOT_NULL(in->buffer);
+			TEST_EQUAL_UI(in->buffer_used, (end2 - i));
+		}
+
+		for (size_t j = 0; j < in->buffer_used; ++j) {
+			TEST_EQUAL_UI(in->buffer[j], byte_at_offset(i + j));
+		}
+
+		diff = eat_all ? in->buffer_used : (in->buffer_used / 2);
+		eat_all = !eat_all;
+
+		in->buffer += diff;
+		in->buffer_used -= diff;
+	}
+
+	TEST_EQUAL_UI(in->buffer_used, 0);
+	TEST_ASSERT(in->eof);
+	sqfs_drop(in);
+	return EXIT_SUCCESS;
+}