Update RequestLogger interface

To improve ergonomics of the request logger, make the interface use a
Logf method that is also already fulfilled by the testing.T struct, so
that this can be passed into the Option without needing adaptation.

client_test.go

@@ -160,10 +160,10 @@ type logStore struct {
 	logs []string
 }
 
-func (l *logStore) Print(s string) {
+func (l *logStore) Logf(format string, args ...any) {
 	l.mu.Lock()
 	defer l.mu.Unlock()
-	l.logs = append(l.logs, s)
+	l.logs = append(l.logs, fmt.Sprintf(format, args...))
 }
 
 func TestRequestLogging(t *testing.T) {

options.go

@@ -47,8 +47,10 @@ func WithRequestValidation() Option {
 	}
 }
 
+// RequestLogger is a minimal interface that can fit for example a testing.T, allowing tests to easily print logs where
+// needed.
 type RequestLogger interface {
-	Print(string)
+	Logf(format string, args ...any)
 }
 
 // WithRequestLogging is a functional Option that provides a logger that copper will use to log out requests and

verifier.go

@@ -108,12 +108,12 @@ func (v *Verifier) Record(res *http.Response) {
 		count := v.reqCounter.Add(1)
 		reqDump, err := httputil.DumpRequestOut(req, true)
 		if err == nil {
-			v.conf.requestLogger.Print(fmt.Sprintf("REQUEST  %04d ====\n%s", count, string(reqDump)))
+			v.conf.requestLogger.Logf("REQUEST  %04d ====\n%s", count, string(reqDump))
 		}
 
 		resDump, err := httputil.DumpResponse(res, true)
 		if err == nil {
-			v.conf.requestLogger.Print(fmt.Sprintf("RESPONSE %04d ====\n%s", count, string(resDump)))
+			v.conf.requestLogger.Logf("RESPONSE %04d ====\n%s", count, string(resDump))
 		}
 	}