Add test for pushgateway client

internal/pushgateway/client.go

@@ -9,6 +9,8 @@ import (
 	"net/http"
 	"time"
 
+	"github.com/matrix-org/dendrite/internal"
+
 	"github.com/opentracing/opentracing-go"
 )
 
@@ -50,8 +52,7 @@ func (h *httpClient) Notify(ctx context.Context, url string, req *NotifyRequest,
 		return err
 	}
 
-	//nolint:errcheck
+	defer internal.CloseAndLogIfError(ctx, hresp.Body, "failed to close response body")
-	defer hresp.Body.Close()
 
 	if hresp.StatusCode == http.StatusOK {
 		return json.NewDecoder(hresp.Body).Decode(resp)

internal/pushgateway/client_test.go

@@ -0,0 +1,54 @@
+package pushgateway
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"reflect"
+	"testing"
+)
+
+func TestNotify(t *testing.T) {
+	wantResponse := NotifyResponse{
+		Rejected: []string{"testing"},
+	}
+
+	var i = 0
+
+	svr := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// /notify only accepts POST requests
+		if r.Method != http.MethodPost {
+			w.WriteHeader(http.StatusNotImplemented)
+			return
+		}
+
+		if i != 0 { // error path
+			w.WriteHeader(http.StatusBadRequest)
+			return
+		}
+
+		// happy path
+		json.NewEncoder(w).Encode(wantResponse)
+	}))
+	defer svr.Close()
+
+	cl := NewHTTPClient(true)
+	gotResponse := NotifyResponse{}
+
+	// Test happy path
+	err := cl.Notify(context.Background(), svr.URL, &NotifyRequest{}, &gotResponse)
+	if err != nil {
+		t.Errorf("failed to notify client")
+	}
+	if !reflect.DeepEqual(gotResponse, wantResponse) {
+		t.Errorf("expected response %+v, got %+v", wantResponse, gotResponse)
+	}
+
+	// Test error path
+	i++
+	err = cl.Notify(context.Background(), svr.URL, &NotifyRequest{}, &gotResponse)
+	if err == nil {
+		t.Errorf("expected notifying the pushgateway to fail, but it succeeded")
+	}
+}