diff --git a/CMakeLists.txt b/CMakeLists.txt
index a3216d1..ba61d2b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -64,6 +64,7 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 if (GGWAVE_ALL_WARNINGS)
     if (CMAKE_COMPILER_IS_GNUCC OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -pedantic")
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -pedantic")
     else()
         # todo : windows
diff --git a/src/ggwave.cpp b/src/ggwave.cpp
index d9f55a2..68bb22d 100644
--- a/src/ggwave.cpp
+++ b/src/ggwave.cpp
@@ -30,8 +30,8 @@ ggwave_Instance ggwave_init(const ggwave_Parameters parameters) {
             parameters.sampleRateIn,
             parameters.sampleRateOut,
             parameters.samplesPerFrame,
-            GGWAVE_SAMPLE_FORMAT_F32,
-            GGWAVE_SAMPLE_FORMAT_I16});
+            parameters.sampleFormatIn,
+            parameters.sampleFormatOut});
 
     return curId++;
 }
@@ -92,6 +92,7 @@ int ggwave_decode(
         std::copy(dataBuffer, dataBuffer + nCopied, (char *) data);
 
         dataSize -= nCopied;
+        dataBuffer += nCopied;
 
         return nCopied;
     };
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index c5af84d..c540a8f 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -1,25 +1,47 @@
 if (EMSCRIPTEN)
     return()
 endif()
+#
+# test-ggwave-c
 
-set(TEST_TARGET test-ggwave)
+set(TEST_TARGET test-ggwave-c)
 
 add_executable(${TEST_TARGET}
-    ${TEST_TARGET}.cpp
+    test-ggwave.c
     )
 
 target_link_libraries(${TEST_TARGET} PRIVATE
     ggwave
     )
 
-add_test(NAME ${TEST_TARGET}-cpp COMMAND $<TARGET_FILE:${TEST_TARGET}>)
+add_test(NAME ${TEST_TARGET} COMMAND $<TARGET_FILE:${TEST_TARGET}>)
+
+#
+# test-ggwave-cpp
+
+set(TEST_TARGET test-ggwave-cpp)
+
+add_executable(${TEST_TARGET}
+    test-ggwave.cpp
+    )
+
+target_link_libraries(${TEST_TARGET} PRIVATE
+    ggwave
+    )
+
+add_test(NAME ${TEST_TARGET} COMMAND $<TARGET_FILE:${TEST_TARGET}>)
 
 if (GGWAVE_SUPPORT_PYTHON)
-    add_test(NAME ${TEST_TARGET}-py
+    #
+    # test-ggwave-py
+
+    set(TEST_TARGET test-ggwave-py)
+
+    add_test(NAME ${TEST_TARGET}
         COMMAND python test-ggwave.py
         WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
         )
 
-    set_tests_properties(${TEST_TARGET}-py
+    set_tests_properties(${TEST_TARGET}
         PROPERTIES ENVIRONMENT "PYTHONPATH=${PROJECT_SOURCE_DIR}/bindings/python")
 endif()
diff --git a/tests/test-ggwave.c b/tests/test-ggwave.c
new file mode 100644
index 0000000..f5521d8
--- /dev/null
+++ b/tests/test-ggwave.c
@@ -0,0 +1,39 @@
+#include "ggwave/ggwave.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define CHECK(cond) \
+    if (!(cond)) { \
+        fprintf(stderr, "[%s:%d] Check failed: %s\n", __FILE__, __LINE__, #cond); \
+        exit(1); \
+    }
+
+#define CHECK_T(cond) CHECK(cond)
+#define CHECK_F(cond) CHECK(!(cond))
+
+int main() {
+    ggwave_Parameters parameters = ggwave_getDefaultParameters();
+    parameters.sampleFormatIn = GGWAVE_SAMPLE_FORMAT_I16;
+    parameters.sampleFormatOut = GGWAVE_SAMPLE_FORMAT_I16;
+
+    ggwave_Instance instance = ggwave_init(parameters);
+
+    int ret;
+    char waveform[1024*1024];
+    const char * payload = "test";
+    char decoded[256];
+
+    ret = ggwave_encode(instance, payload, 4, GGWAVE_TX_PROTOCOL_AUDIBLE_FAST, 50, waveform);
+    CHECK(ret > 0);
+
+    ret = ggwave_decode(instance, waveform, sizeof(int16_t)*ret, decoded);
+    CHECK(ret == 4);
+
+    CHECK(strcmp(decoded, payload) == 0);
+
+    ggwave_free(instance);
+
+    return 0;
+}