fix: add test util to wait for healthy piri (#306)

Aims to fix:

```
=== RUN   TestFXSpaceContentRetrieve/space/content/retrieve
    ucan_fx_test.go:106: 
            Error Trace:    /Users/runner/work/piri/piri/pkg/service/retrieval/ucan_fx_test.go:106
            Error:          Received unexpected error:
                            sending message: doing HTTP request: Get "http://localhost:49232/piece/bafkreibmtmy3p773cf7uj24hfg2dhniov45xv4p54cs4oe3nxhm7p3ov5e": dial tcp [::1]:49232: connect: connection refused
```

Possibly because the server is not ready to accept connections yet.

Author: alanshaw

pkg/internal/testutil/environment.go

@@ -2,8 +2,11 @@ package testutil
 
 import (
 	"net"
+	"net/http"
+	"net/url"
 	"os"
 	"testing"
+	"time"
 
 	docker_client "github.com/docker/docker/client"
 	"github.com/stretchr/testify/require"
@@ -44,3 +47,20 @@ func IsDockerAvailable(t testing.TB) bool {
 	}
 	return true
 }
+
+// WaitForHealthy waits for the URL to return HTTP 200 for up to 10 seconds.
+func WaitForHealthy(t testing.TB, url *url.URL) {
+	t.Helper()
+	start := time.Now()
+	for i := 0; i < 100; i++ {
+		resp, err := http.DefaultClient.Get(url.String())
+		if err == nil {
+			resp.Body.Close()
+			if resp.StatusCode == http.StatusOK {
+				return
+			}
+		}
+		time.Sleep(time.Millisecond * 100)
+	}
+	t.Fatalf("%s was not healthy after %s", url.String(), time.Since(start).String())
+}

pkg/service/retrieval/ucan_fx_test.go

@@ -39,6 +39,7 @@ func TestFXSpaceContentRetrieve(t *testing.T) {
 
 	testApp.RequireStart()
 	defer testApp.RequireStop()
+	piritestutil.WaitForHealthy(t, &appConfig.Server.PublicURL)
 
 	t.Run("space/content/retrieve", func(t *testing.T) {
 		space := testutil.RandomSigner(t)
@@ -141,6 +142,7 @@ func TestFXBlobRetrieve(t *testing.T) {
 
 	testApp.RequireStart()
 	defer testApp.RequireStop()
+	piritestutil.WaitForHealthy(t, &appConfig.Server.PublicURL)
 
 	t.Run("blob/retrieve", func(t *testing.T) {
 		randBytes := testutil.RandomBytes(t, 256)

pkg/service/storage/ucan_access_fx_test.go

@@ -55,6 +55,7 @@ func TestFXAccessGrant(t *testing.T) {
 
 	testApp.RequireStart()
 	defer testApp.RequireStop()
+	piritestutil.WaitForHealthy(t, &appConfig.Server.PublicURL)
 
 	channel := http.NewChannel(&appConfig.Server.PublicURL)
 	conn, err := client.NewConnection(granter, channel)