thodg/libgit2

diff --git a/src/graph.c b/src/graph.c
index 96fda7a..1c64411 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -180,7 +180,7 @@ int git_graph_descendant_of(git_repository *repo, const git_oid *commit, const g
 	if (git_oid_equal(commit, ancestor))
 		return 0;
 
-	if ((error = git_merge_base(&merge_base, repo, commit, ancestor) < 0))
+	if ((error = git_merge_base(&merge_base, repo, commit, ancestor)) < 0)
 		return error;
 
 	return git_oid_equal(&merge_base, ancestor);
diff --git a/tests/graph/descendant_of.c b/tests/graph/descendant_of.c
index ffdd0cf..8e9952a 100644
--- a/tests/graph/descendant_of.c
+++ b/tests/graph/descendant_of.c
@@ -45,3 +45,11 @@ void test_graph_descendant_of__returns_correct_result(void)
 	git_commit_free(other);
 
 }
+
+void test_graph_descendant_of__nopath(void)
+{
+	git_oid oid;
+
+	git_oid_fromstr(&oid, "e90810b8df3e80c413d903f631643c716887138d");
+	cl_assert_equal_i(0, git_graph_descendant_of(_repo, git_commit_id(commit), &oid));
+}