Improve dual link test to compile against zlib. Previously we were only linking against it.

.github/workflows/cmake.yml

@@ -83,12 +83,6 @@ jobs:
             cmake-args: -DWITH_OPTIM=OFF -DHAVE_BUILTIN_CTZLL=OFF -DHAVE_BUILTIN_CTZ=OFF
             codecov: ubuntu_gcc_no_ctz
 
-          - name: Ubuntu GCC Link Zlib
-            os: ubuntu-latest
-            compiler: gcc
-            cxx-compiler: g++
-            cmake-args: -DZLIB_DUAL_LINK=ON
-
           - name: Ubuntu GCC No AVX2 UBSAN
             os: ubuntu-latest
             compiler: gcc

CMakeLists.txt

@@ -1191,12 +1191,6 @@ if(ZLIB_ENABLE_TESTS)
             target_compile_definitions(${target} PUBLIC -DWITH_GZFILEOP)
             target_sources(${target} PRIVATE ${ZLIB_GZFILE_PRIVATE_HDRS} ${ZLIB_GZFILE_SRCS})
         endif()
-        if(ZLIB_DUAL_LINK)
-            find_package(ZLIB)
-            if(ZLIB_FOUND)
-                target_link_libraries(${target} ${ZLIB_LIBRARIES})
-            endif()
-        endif()
     endmacro()
 
     macro(add_simple_test_executable target)

test/CMakeLists.txt

@@ -95,6 +95,21 @@ if(WITH_SANITIZER STREQUAL "Memory")
         -fsanitize-memory-track-origins)
 endif()
 
+if(ZLIB_DUAL_LINK AND NOT ZLIB_COMPAT)
+    find_package(ZLIB)
+    if(ZLIB_FOUND)
+        message(STATUS "Added dual linking tests against zlib")
+        message(STATUS "  Zlib include dir: ${ZLIB_INCLUDE_DIR}")
+        message(STATUS "  Zlib libraries: ${ZLIB_LIBRARIES}")
+
+        target_sources(gtest_zlib PRIVATE test_compress_dual.cc)
+        target_include_directories(gtest_zlib PRIVATE ${ZLIB_INCLUDE_DIR})
+        target_link_libraries(gtest_zlib ${ZLIB_LIBRARIES})
+    else()
+        message(WARNING "Zlib not found, skipping dual linking tests")
+    endif()
+endif()
+
 target_link_libraries(gtest_zlib zlibstatic GTest::GTest)
 
 find_package(Threads)

test/test_compress_dual.cc

@@ -0,0 +1,28 @@
+/* test_compress_dual.cc - Test linking against both zlib and zlib-ng */
+
+#include "zlib.h"
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_shared.h"
+
+#include <gtest/gtest.h>
+
+TEST(compress, basic_zlib) {
+    Byte compr[128], uncompr[128];
+    uLong compr_len = sizeof(compr), uncompr_len = sizeof(uncompr);
+    int err;
+
+    err = compress(compr, &compr_len, (const unsigned char *)hello, hello_len);
+    EXPECT_EQ(err, Z_OK);
+
+    strcpy((char*)uncompr, "garbage");
+
+    err = uncompress(uncompr, &uncompr_len, compr, compr_len);
+    EXPECT_EQ(err, Z_OK);
+
+    EXPECT_STREQ((char *)uncompr, (char *)hello);
+}