tests: rename remaining C unit tests to .cpp (no content changes)

tests/test_buffer_cpp.cpp

@@ -0,0 +1,103 @@
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+
+int verbose = 0;
+
+#include "crypto.h"
+
+/* Provide nonce_cache symbol needed by crypto.cpp */
+struct cache *nonce_cache = NULL;
+
+static void
+test_balloc(void)
+{
+    buffer_t buf;
+    memset(&buf, 0, sizeof(buf));
+
+    int ret = balloc(&buf, 100);
+    assert(ret == 100);
+    (void)ret;
+    assert(buf.data != NULL);
+    assert(buf.capacity >= 100);
+    assert(buf.len == 0);
+    assert(buf.idx == 0);
+
+    bfree(&buf);
+    assert(buf.data == NULL);
+    assert(buf.capacity == 0);
+}
+
+static void
+test_brealloc(void)
+{
+    buffer_t buf;
+    memset(&buf, 0, sizeof(buf));
+
+    balloc(&buf, 50);
+    buf.len = 10;
+
+    /* Grow the buffer */
+    int ret = brealloc(&buf, 10, 200);
+    assert(ret == 200);
+    (void)ret;
+    assert(buf.capacity >= 200);
+    assert(buf.len == 10);
+
+    bfree(&buf);
+}
+
+static void
+test_bprepend(void)
+{
+    buffer_t dst, src;
+    memset(&dst, 0, sizeof(dst));
+    memset(&src, 0, sizeof(src));
+
+    balloc(&dst, 100);
+    balloc(&src, 100);
+
+    /* Put some data in src */
+    memcpy(src.data, "HEADER", 6);
+    src.len = 6;
+
+    /* Put some data in dst */
+    memcpy(dst.data, "BODY", 4);
+    dst.len = 4;
+
+    int ret = bprepend(&dst, &src, 200);
+    assert(ret == 10);
+    (void)ret;
+    assert(dst.len == 10);
+    assert(memcmp(dst.data, "HEADERBODY", 10) == 0);
+
+    bfree(&dst);
+    bfree(&src);
+}
+
+static void
+test_balloc_zero(void)
+{
+    buffer_t buf;
+    memset(&buf, 0, sizeof(buf));
+
+    int ret = balloc(&buf, 0);
+    assert(ret == 0);
+    (void)ret;
+    /* A zero-capacity buffer should still succeed */
+    bfree(&buf);
+}
+
+int
+main(void)
+{
+    test_balloc();
+    test_brealloc();
+    test_bprepend();
+    test_balloc_zero();
+    return 0;
+}