diff --git a/tests/hwc/Android.mk b/tests/hwc/Android.mk
index 0416ff1..a5f59f1 100644
--- a/tests/hwc/Android.mk
+++ b/tests/hwc/Android.mk
@@ -1,9 +1,9 @@
 LOCAL_PATH:= $(call my-dir)
 
 include $(CLEAR_VARS)
-LOCAL_MODULE := libcnativewindow 
+LOCAL_MODULE := libcnativewindow
 LOCAL_SRC_FILES := cnativewindow.c util.c
-LOCAL_CFLAGS := -Wno-unused-parameter
+LOCAL_CFLAGS := -Wall -Werror -Wno-unused-parameter
 LOCAL_SHARED_LIBRARIES := libEGL libGLESv2 libdl libhardware libnativewindow
 include $(BUILD_STATIC_LIBRARY)
 
@@ -12,5 +12,5 @@
 LOCAL_SRC_FILES := test-arrows.c
 LOCAL_STATIC_LIBRARIES := libcnativewindow
 LOCAL_SHARED_LIBRARIES := libEGL libGLESv2 libdl libhardware libnativewindow
-LOCAL_CFLAGS := -DGL_GLEXT_PROTOTYPES
+LOCAL_CFLAGS := -DGL_GLEXT_PROTOTYPES -Wall -Werror
 include $(BUILD_EXECUTABLE)
diff --git a/tests/hwc/cnativewindow.c b/tests/hwc/cnativewindow.c
index 5b1d78e..65a814d 100644
--- a/tests/hwc/cnativewindow.c
+++ b/tests/hwc/cnativewindow.c
@@ -181,7 +181,7 @@
 	hwc_composer_device_1_t *hwc = win->hwc;
 	hwc_display_contents_1_t *dc = &(win->dc);
 	hwc_layer_1_t *dl = win->dc.hwLayers;
-	int r, i;
+	int r;
 
 	dc->retireFenceFd = -1;
 	dc->outbufAcquireFenceFd = -1;
@@ -462,8 +462,8 @@
 	hw_module_t const* module;
 	framebuffer_device_t *fb = NULL;
 	alloc_device_t *gr;
-	int err, i, n;
-	unsigned usage, format;
+	int err, i;
+	unsigned usage;
 
 	memset(win, 0, sizeof(CNativeWindow));
 
diff --git a/tests/hwc/util.c b/tests/hwc/util.c
index 8931305..51d5974 100644
--- a/tests/hwc/util.c
+++ b/tests/hwc/util.c
@@ -36,7 +36,7 @@
 	m[7] = -1.0;
 	m[8] = 0.0;
 	m[9] = 0.0;
-	m[10] -1.0;
+	m[10] = -1.0;
 	m[11] = 0.0;
 	m[12] = 0.0;
 	m[13] = 0.0;
@@ -111,7 +111,7 @@
 
 int select_config_for_window(EGLDisplay dpy, EGLint *attr,
 	unsigned format, EGLConfig *config) {
-	EGLint R,G,B,A,r,g,b,a;
+	EGLint R,G,B,A;
 	EGLint i, n, max;
 	EGLConfig *cfg;