thodg/libgit2

diff --git a/src/index.c b/src/index.c
index 214d29d..6c04177 100644
--- a/src/index.c
+++ b/src/index.c
@@ -259,7 +259,7 @@ int git_index_open(git_index **index_out, const char *index_path)
 {
 	git_index *index;
 
-	assert(index_out && index_path);
+	assert(index_out);
 
 	index = git__calloc(1, sizeof(git_index));
 	GITERR_CHECK_ALLOC(index);
diff --git a/tests-clar/index/inmemory.c b/tests-clar/index/inmemory.c
new file mode 100644
index 0000000..9c5c0b7
--- /dev/null
+++ b/tests-clar/index/inmemory.c
@@ -0,0 +1,11 @@
+#include "clar_libgit2.h"
+
+void test_index_inmemory__can_create_an_inmemory_index(void)
+{
+	git_index *index;
+
+	cl_git_pass(git_index_new(&index));
+	cl_assert_equal_i(0, git_index_entrycount(index));
+
+	git_index_free(index);
+}