diff -r a786b0a89b37 -r 74d777455e96 tests/test_allocator.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test_allocator.c	Sat Dec 30 14:32:42 2023 +0100
@@ -0,0 +1,145 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2023 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "cx/test.h"
+
+#include "cx/allocator.h"
+
+CX_TEST(test_allocator_default) {
+    CX_TEST_DO {
+        CX_TEST_ASSERT(cxDefaultAllocator->cl != NULL);
+    }
+}
+
+CX_TEST(test_allocator_default_malloc) {
+    void *test = cxMalloc(cxDefaultAllocator, 16);
+    CX_TEST_DO {
+        CX_TEST_ASSERT(test != NULL);
+        // we cannot assert sth. but valgrind will detect an error
+        memcpy(test, "0123456789ABCDEF", 16);
+    }
+    free(test);
+}
+
+CX_TEST(test_allocator_default_calloc) {
+    char *test = cxCalloc(cxDefaultAllocator, 8, 2);
+    CX_TEST_DO {
+        CX_TEST_ASSERT(test != NULL);
+        for (int i = 0; i < 16; i++) {
+            CX_TEST_ASSERT(test[i] == 0);
+        }
+    }
+    free(test);
+}
+
+CX_TEST(test_allocator_default_realloc) {
+    char *test = calloc(8, 1);
+    memcpy(test, "Test", 5);
+    CX_TEST_DO {
+        test = cxRealloc(cxDefaultAllocator, test, 16);
+        CX_TEST_ASSERT(test != NULL);
+        CX_TEST_ASSERT(0 == strcmp(test, "Test"));
+    }
+    free(test);
+}
+
+CX_TEST(test_allocator_default_free) {
+    void *test = malloc(16);
+    CX_TEST_DO {
+        // we cannot assert sth. but valgrind will detect an error
+        cxFree(cxDefaultAllocator, test);
+        CX_TEST_ASSERT(true);
+    }
+}
+
+CX_TEST(test_allocator_reallocate) {
+    void *test = calloc(8, 1);
+    memcpy(test, "Test", 5);
+    CX_TEST_DO {
+        int ret = cxReallocate(cxDefaultAllocator, &test, 16);
+        CX_TEST_ASSERT(ret == 0);
+        CX_TEST_ASSERT(test != NULL);
+        CX_TEST_ASSERT(0 == strcmp(test, "Test"));
+    }
+    free(test);
+}
+
+CX_TEST(test_allocator_reallocate_low_level) {
+    void *test = calloc(8, 1);
+    memcpy(test, "Test", 5);
+    CX_TEST_DO {
+        int ret = cx_reallocate(&test, 16);
+        CX_TEST_ASSERT(ret == 0);
+        CX_TEST_ASSERT(test != NULL);
+        CX_TEST_ASSERT(0 == strcmp(test, "Test"));
+    }
+    free(test);
+}
+
+static void *test_allocator_mock_failing_realloc(
+        __attribute__((__unused__))void *p,
+        __attribute__((__unused__))void *d,
+        __attribute__((__unused__))size_t n
+) {
+    return NULL;
+}
+
+CX_TEST(test_allocator_reallocate_fails) {
+    // Mock an allocator that always returns NULL on realloc
+    cx_allocator_class mock_cl;
+    mock_cl.realloc = test_allocator_mock_failing_realloc;
+    CxAllocator mock = {&mock_cl, NULL};
+
+    void *test = calloc(8, 1);
+    memcpy(test, "Test", 5);
+    void *original = test;
+    CX_TEST_DO {
+        int ret = cxReallocate(&mock, &test, 16);
+        // non-zero return code because of the failure
+        CX_TEST_ASSERT(ret != 0);
+        // the test pointer was not changed and still points to the same memory
+        CX_TEST_ASSERT(test == original);
+        CX_TEST_ASSERT(0 == strcmp(test, "Test"));
+    }
+    free(test);
+}
+
+CxTestSuite *cx_test_suite_allocator(void) {
+    CxTestSuite *suite = cx_test_suite_new("allocator");
+
+    cx_test_register(suite, test_allocator_default);
+    cx_test_register(suite, test_allocator_default_malloc);
+    cx_test_register(suite, test_allocator_default_calloc);
+    cx_test_register(suite, test_allocator_default_realloc);
+    cx_test_register(suite, test_allocator_default_free);
+    cx_test_register(suite, test_allocator_reallocate);
+    cx_test_register(suite, test_allocator_reallocate_fails);
+    cx_test_register(suite, test_allocator_reallocate_low_level);
+
+    return suite;
+}