test: use port polling to wait for server to start

Previously tests did not wait for the server to start listening on the port. This could lead to race conditions and flaky tests. This commit adds a port polling loop that waits for the server to start listening on the port before running the tests. Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
prometheus · Mar 7, 2023 · a672922 · a672922
1 parent c9d6337
commit a672922
Showing 1 changed file with 26 additions and 0 deletions.
diff --git a/web/handler_test.go b/web/handler_test.go
@@ -15,9 +15,11 @@ package web
 
 import (
 	"context"
+	"net"
 	"net/http"
 	"sync"
 	"testing"
+	"time"
 )
 
 // TestBasicAuthCache validates that the cache is working by calling a password
@@ -47,6 +49,8 @@ func TestBasicAuthCache(t *testing.T) {
 		close(done)
 	}()
 
+	waitForPort(t, port)
+
 	login := func(username, password string, code int) {
 		client := &http.Client{}
 		req, err := http.NewRequest("GET", "http://localhost"+port, nil)
@@ -115,6 +119,8 @@ func TestBasicAuthWithFakepassword(t *testing.T) {
 		close(done)
 	}()
 
+	waitForPort(t, port)
+
 	login := func() {
 		client := &http.Client{}
 		req, err := http.NewRequest("GET", "http://localhost"+port, nil)
@@ -163,6 +169,8 @@ func TestByPassBasicAuthVuln(t *testing.T) {
 		close(done)
 	}()
 
+	waitForPort(t, port)
+
 	login := func(username, password string) {
 		client := &http.Client{}
 		req, err := http.NewRequest("GET", "http://localhost"+port, nil)
@@ -211,6 +219,8 @@ func TestHTTPHeaders(t *testing.T) {
 		close(done)
 	}()
 
+	waitForPort(t, port)
+
 	client := &http.Client{}
 	req, err := http.NewRequest("GET", "http://localhost"+port, nil)
 	if err != nil {
@@ -232,3 +242,19 @@ func TestHTTPHeaders(t *testing.T) {
 		}
 	}
 }
+
+func waitForPort(t *testing.T, addr string) {
+	start := time.Now()
+	for {
+		conn, err := net.DialTimeout("tcp", addr, time.Second)
+		if err == nil {
+			conn.Close()
+			return
+		}
+		if time.Since(start) >= 5*time.Second {
+			t.Fatalf("timeout waiting for port %s: %s", addr, err)
+			return
+		}
+		time.Sleep(time.Millisecond * 100)
+	}
+}