diff --git a/tests/test_document.c b/tests/test_document.c
index 3f32417..19c34ad 100644
--- a/tests/test_document.c
+++ b/tests/test_document.c
@@ -6,10 +6,10 @@
 #include "tests.h"
 
 START_TEST(test_open) {
-  fail_unless(zathura_document_open(NULL, NULL, NULL, NULL, NULL) == NULL, "Could create document", NULL);
-  fail_unless(zathura_document_open(NULL, "fl", NULL, NULL, NULL) == NULL, "Could create document", NULL);
-  fail_unless(zathura_document_open(NULL, "fl", "ur", NULL, NULL) == NULL, "Could create document", NULL);
-  fail_unless(zathura_document_open(NULL, "fl", NULL, "pw", NULL) == NULL, "Could create document", NULL);
+  ck_assert_ptr_null(zathura_document_open(NULL, NULL, NULL, NULL, NULL));
+  ck_assert_ptr_null(zathura_document_open(NULL, "fl", NULL, NULL, NULL));
+  ck_assert_ptr_null(zathura_document_open(NULL, "fl", "ur", NULL, NULL));
+  ck_assert_ptr_null(zathura_document_open(NULL, "fl", NULL, "pw", NULL));
 } END_TEST
 
 static Suite* suite_document(void)
diff --git a/tests/test_sandbox.c b/tests/test_sandbox.c
index efc8781..40246d8 100644
--- a/tests/test_sandbox.c
+++ b/tests/test_sandbox.c
@@ -8,8 +8,8 @@
 START_TEST(test_create) {
   zathura_t* zathura = zathura_create();
   zathura->global.sandbox = ZATHURA_SANDBOX_STRICT;
-  fail_unless(zathura != NULL, "Could not create strictly sandboxed session", NULL);
-  fail_unless(zathura_init(zathura) == true, "Could not initialize strictly sandboxed session", NULL);
+  ck_assert_ptr_nonnull(zathura);
+  ck_assert(zathura_init(zathura));
   zathura_free(zathura);
 } END_TEST
 
diff --git a/tests/test_session.c b/tests/test_session.c
index 09c7086..d18a297 100644
--- a/tests/test_session.c
+++ b/tests/test_session.c
@@ -7,8 +7,8 @@
 
 START_TEST(test_create) {
   zathura_t* zathura = zathura_create();
-  fail_unless(zathura != NULL, "Could not create session", NULL);
-  fail_unless(zathura_init(zathura) == true, "Could not initialize session", NULL);
+  ck_assert_ptr_nonnull(zathura);
+  ck_assert(zathura_init(zathura));
   zathura_free(zathura);
 } END_TEST
 
diff --git a/tests/test_types.c b/tests/test_types.c
index c6db5f7..f6e3b5b 100644
--- a/tests/test_types.c
+++ b/tests/test_types.c
@@ -7,12 +7,12 @@
 #include "tests.h"
 
 START_TEST(test_image_buffer_fail) {
-  fail_unless(zathura_image_buffer_create(UINT_MAX, UINT_MAX) == NULL, NULL);
+  ck_assert_ptr_null(zathura_image_buffer_create(UINT_MAX, UINT_MAX));
 } END_TEST
 
 START_TEST(test_image_buffer) {
   zathura_image_buffer_t* buffer = zathura_image_buffer_create(1, 1);
-  fail_unless(buffer != NULL, NULL);
+  ck_assert_ptr_nonnull(buffer);
   zathura_image_buffer_free(buffer);
 } END_TEST
 
diff --git a/tests/test_utils.c b/tests/test_utils.c
index b46ab06..7d91ec4 100644
--- a/tests/test_utils.c
+++ b/tests/test_utils.c
@@ -6,9 +6,9 @@
 #include "tests.h"
 
 START_TEST(test_file_valid_extension_null) {
-  fail_unless(file_valid_extension(NULL, NULL) == false, NULL);
-  fail_unless(file_valid_extension((void*) 0xDEAD, NULL) == false, NULL);
-  fail_unless(file_valid_extension(NULL, "pdf") == false, NULL);
+  ck_assert(file_valid_extension(NULL, NULL) == false);
+  ck_assert(file_valid_extension((void*) 0xDEAD, NULL) == false);
+  ck_assert(file_valid_extension(NULL, "pdf") == false);
 } END_TEST
 
 static Suite* suite_utils(void)
diff --git a/tests/tests.c b/tests/tests.c
index faf34bb..649d54d 100644
--- a/tests/tests.c
+++ b/tests/tests.c
@@ -32,5 +32,5 @@ int run_suite(Suite* suite)
 
 void setup(void)
 {
-  fail_unless(gtk_init_check(NULL, NULL) == TRUE, "GTK+ initializitation failed", NULL);
+  ck_assert_msg(gtk_init_check(NULL, NULL) == TRUE, "GTK+ initializitation failed");
 }