fix: Gracefully handle HTTP errors

Return error in case of an unexpeted response.

Author: macie

hackernews.go

@@ -3,6 +3,7 @@ package opinions
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"io"
 	"net/url"
 	"time"
@@ -38,6 +39,10 @@ func SearchHackerNews(ctx context.Context, client http.Client, query string) ([]
 	}
 	defer r.Body.Close()
 
+	if r.StatusCode != http.StatusOK {
+		return discussions, fmt.Errorf("cannot search Hacker News: status code %d", r.StatusCode)
+	}
+
 	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		return discussions, err

http/client.go

@@ -8,6 +8,11 @@ import (
 	"runtime"
 )
 
+// Selected HTTP status codes as registered with IANA. See: https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
+const (
+	StatusOK = 200
+)
+
 // A Client is an HTTP client.
 type Client struct {
 	defaultClient http.Client

lobsters.go

@@ -2,6 +2,7 @@ package opinions
 
 import (
 	"context"
+	"fmt"
 	"net/url"
 	"strconv"
 
@@ -27,6 +28,10 @@ func SearchLobsters(ctx context.Context, client http.Client, query string) ([]Di
 	}
 	defer r.Body.Close()
 
+	if r.StatusCode != http.StatusOK {
+		return discussions, fmt.Errorf("cannot search Lobsters: status code %d", r.StatusCode)
+	}
+
 	body, err := html.Parse(r.Body)
 	if err != nil {
 		return discussions, err