diff --git a/src/http2_test.cc b/src/http2_test.cc
index 35dbe93f..13c927ef 100644
--- a/src/http2_test.cc
+++ b/src/http2_test.cc
@@ -270,4 +270,16 @@ void test_http2_parse_http_status_code(void) {
   CU_ASSERT(-1 == http2::parse_http_status_code(""));
 }
 
+void test_http2_index_header(void) {
+  int hdidx[http2::HD_MAXIDX];
+  http2::init_hdidx(hdidx);
+
+  http2::index_header(hdidx, reinterpret_cast<const uint8_t *>(":authority"),
+                      10, 0);
+  http2::index_header(hdidx, reinterpret_cast<const uint8_t *>("hos"), 3, 1);
+
+  CU_ASSERT(0 == hdidx[http2::HD_AUTHORITY]);
+  CU_ASSERT(-1 == hdidx[http2::HD_HOST]);
+}
+
 } // namespace shrpx
diff --git a/src/http2_test.h b/src/http2_test.h
index 9e1e2fc0..2cb8e69b 100644
--- a/src/http2_test.h
+++ b/src/http2_test.h
@@ -36,6 +36,7 @@ void test_http2_build_http1_headers_from_norm_headers(void);
 void test_http2_lws(void);
 void test_http2_rewrite_location_uri(void);
 void test_http2_parse_http_status_code(void);
+void test_http2_index_header(void);
 
 } // namespace shrpx
 
diff --git a/src/shrpx-unittest.cc b/src/shrpx-unittest.cc
index 1e4e2041..f1eb2d83 100644
--- a/src/shrpx-unittest.cc
+++ b/src/shrpx-unittest.cc
@@ -86,6 +86,8 @@ int main(int argc, char *argv[]) {
                    shrpx::test_http2_rewrite_location_uri) ||
       !CU_add_test(pSuite, "http2_parse_http_status_code",
                    shrpx::test_http2_parse_http_status_code) ||
+      !CU_add_test(pSuite, "http2_index_header",
+                   shrpx::test_http2_index_header) ||
       !CU_add_test(pSuite, "downstream_normalize_request_headers",
                    shrpx::test_downstream_normalize_request_headers) ||
       !CU_add_test(pSuite, "downstream_normalize_response_headers",