diff --git a/src/shrpx-unittest.cc b/src/shrpx-unittest.cc
index 88c1dc40..7f9bd806 100644
--- a/src/shrpx-unittest.cc
+++ b/src/shrpx-unittest.cc
@@ -117,6 +117,8 @@ int main(int argc, char *argv[]) {
                    shrpx::test_downstream_rewrite_location_response_header) ||
       !CU_add_test(pSuite, "downstream_supports_non_final_response",
                    shrpx::test_downstream_supports_non_final_response) ||
+      !CU_add_test(pSuite, "downstream_find_affinity_cookie",
+                   shrpx::test_downstream_find_affinity_cookie) ||
       !CU_add_test(pSuite, "config_parse_header",
                    shrpx::test_shrpx_config_parse_header) ||
       !CU_add_test(pSuite, "config_parse_log_format",
@@ -131,6 +133,8 @@ int main(int argc, char *argv[]) {
                    shrpx::test_shrpx_http_create_forwarded) ||
       !CU_add_test(pSuite, "http_create_via_header_value",
                    shrpx::test_shrpx_http_create_via_header_value) ||
+      !CU_add_test(pSuite, "http_create_affinity_cookie",
+                   shrpx::test_shrpx_http_create_affinity_cookie) ||
       !CU_add_test(pSuite, "router_match", shrpx::test_shrpx_router_match) ||
       !CU_add_test(pSuite, "router_match_wildcard",
                    shrpx::test_shrpx_router_match_wildcard) ||
diff --git a/src/shrpx_downstream_test.cc b/src/shrpx_downstream_test.cc
index fc8c54a8..98514437 100644
--- a/src/shrpx_downstream_test.cc
+++ b/src/shrpx_downstream_test.cc
@@ -189,4 +189,38 @@ void test_downstream_supports_non_final_response(void) {
   CU_ASSERT(!d.supports_non_final_response());
 }
 
+void test_downstream_find_affinity_cookie(void) {
+  Downstream d(nullptr, nullptr, 0);
+
+  auto &req = d.request();
+  req.fs.add_header_token(StringRef::from_lit("cookie"), StringRef{}, false,
+                          http2::HD_COOKIE);
+  req.fs.add_header_token(StringRef::from_lit("cookie"),
+                          StringRef::from_lit("a=b;;c=d"), false,
+                          http2::HD_COOKIE);
+  req.fs.add_header_token(StringRef::from_lit("content-length"),
+                          StringRef::from_lit("599"), false,
+                          http2::HD_CONTENT_LENGTH);
+  req.fs.add_header_token(StringRef::from_lit("cookie"),
+                          StringRef::from_lit("lb=deadbeef;LB=f1f2f3f4"), false,
+                          http2::HD_COOKIE);
+  req.fs.add_header_token(StringRef::from_lit("cookie"),
+                          StringRef::from_lit("short=e1e2e3e"), false,
+                          http2::HD_COOKIE);
+
+  uint32_t aff;
+
+  aff = d.find_affinity_cookie(StringRef::from_lit("lb"));
+
+  CU_ASSERT(0xdeadbeef == aff);
+
+  aff = d.find_affinity_cookie(StringRef::from_lit("LB"));
+
+  CU_ASSERT(0xf1f2f3f4 == aff);
+
+  aff = d.find_affinity_cookie(StringRef::from_lit("short"));
+
+  CU_ASSERT(0 == aff);
+}
+
 } // namespace shrpx
diff --git a/src/shrpx_downstream_test.h b/src/shrpx_downstream_test.h
index c042de17..d9153ee5 100644
--- a/src/shrpx_downstream_test.h
+++ b/src/shrpx_downstream_test.h
@@ -37,6 +37,7 @@ void test_downstream_crumble_request_cookie(void);
 void test_downstream_assemble_request_cookie(void);
 void test_downstream_rewrite_location_response_header(void);
 void test_downstream_supports_non_final_response(void);
+void test_downstream_find_affinity_cookie(void);
 
 } // namespace shrpx
 
diff --git a/src/shrpx_http_test.cc b/src/shrpx_http_test.cc
index eaf67adc..0fdcc93b 100644
--- a/src/shrpx_http_test.cc
+++ b/src/shrpx_http_test.cc
@@ -91,4 +91,31 @@ void test_shrpx_http_create_via_header_value(void) {
   CU_ASSERT(("2 nghttpx" == StringRef{std::begin(buf), end}));
 }
 
+void test_shrpx_http_create_affinity_cookie(void) {
+  BlockAllocator balloc(1024, 1024);
+  StringRef c;
+
+  c = http::create_affinity_cookie(balloc, StringRef::from_lit("cookie-val"),
+                                   0xf1e2d3c4u, StringRef{}, false);
+
+  CU_ASSERT("cookie-val=f1e2d3c4" == c);
+
+  c = http::create_affinity_cookie(balloc, StringRef::from_lit("alpha"),
+                                   0x00000000u, StringRef{}, true);
+
+  CU_ASSERT("alpha=00000000; Secure" == c);
+
+  c = http::create_affinity_cookie(balloc, StringRef::from_lit("bravo"),
+                                   0x01111111u, StringRef::from_lit("bar"),
+                                   false);
+
+  CU_ASSERT("bravo=01111111; Path=bar" == c);
+
+  c = http::create_affinity_cookie(balloc, StringRef::from_lit("charlie"),
+                                   0x01111111u, StringRef::from_lit("bar"),
+                                   true);
+
+  CU_ASSERT("charlie=01111111; Path=bar; Secure" == c);
+}
+
 } // namespace shrpx
diff --git a/src/shrpx_http_test.h b/src/shrpx_http_test.h
index 7692c95a..85d2947d 100644
--- a/src/shrpx_http_test.h
+++ b/src/shrpx_http_test.h
@@ -33,6 +33,7 @@ namespace shrpx {
 
 void test_shrpx_http_create_forwarded(void);
 void test_shrpx_http_create_via_header_value(void);
+void test_shrpx_http_create_affinity_cookie(void);
 
 } // namespace shrpx