Add a unit test for heuristicsCopyFileLogs

Signed-off-by: Stephen Kitt <skitt@redhat.com>

pkg/kubelet/kubelet_server_journal.go

@@ -343,7 +343,7 @@ func copyFileLogs(ctx context.Context, w io.Writer, services []string) {
 	}
 
 	for _, service := range services {
-		heuristicsCopyFileLogs(ctx, w, service)
+		heuristicsCopyFileLogs(ctx, w, nodeLogDir, service)
 	}
 }
 
@@ -352,7 +352,7 @@ func copyFileLogs(ctx context.Context, w io.Writer, services []string) {
 // /var/log/service.log or
 // /var/log/service/service.log or
 // in that order stopping on first success.
-func heuristicsCopyFileLogs(ctx context.Context, w io.Writer, service string) {
+func heuristicsCopyFileLogs(ctx context.Context, w io.Writer, logDir, service string) {
 	logFileNames := [3]string{
 		service,
 		fmt.Sprintf("%s.log", service),
@@ -362,7 +362,7 @@ func heuristicsCopyFileLogs(ctx context.Context, w io.Writer, service string) {
 	var err error
 	for _, logFileName := range logFileNames {
 		var logFile string
-		logFile, err = securejoin.SecureJoin(nodeLogDir, logFileName)
+		logFile, err = securejoin.SecureJoin(logDir, logFileName)
 		if err != nil {
 			break
 		}

pkg/kubelet/kubelet_server_journal_test.go

@@ -17,7 +17,11 @@ limitations under the License.
 package kubelet
 
 import (
+	"bytes"
+	"context"
 	"net/url"
+	"os"
+	"path/filepath"
 	"reflect"
 	"runtime"
 	"strings"
@@ -221,3 +225,64 @@ func Test_nodeLogQuery_validate(t *testing.T) {
 		})
 	}
 }
+
+func Test_heuristicsCopyFileLogs(t *testing.T) {
+	ctx := context.TODO()
+	buf := &bytes.Buffer{}
+
+	dir, err := os.MkdirTemp("", "logs")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = os.RemoveAll(dir) }()
+
+	// Check missing logs
+	heuristicsCopyFileLogs(ctx, buf, dir, "service.log")
+	if !strings.Contains(buf.String(), "log not found for service.log") {
+		t.Fail()
+	}
+	buf.Reset()
+
+	// Check missing service logs
+	heuristicsCopyFileLogs(ctx, buf, dir, "service")
+	if !strings.Contains(buf.String(), "log not found for service") {
+		t.Fail()
+	}
+	buf.Reset()
+
+	// Check explicitly-named files
+	if err := os.WriteFile(filepath.Join(dir, "service.log"), []byte("valid logs"), 0o444); err != nil {
+		t.Fatal(err)
+	}
+	heuristicsCopyFileLogs(ctx, buf, dir, "service.log")
+	if buf.String() != "valid logs" {
+		t.Fail()
+	}
+	buf.Reset()
+
+	// Check service logs
+	heuristicsCopyFileLogs(ctx, buf, dir, "service")
+	if buf.String() != "valid logs" {
+		t.Fail()
+	}
+	buf.Reset()
+
+	// Check that a directory doesn't cause errors
+	if err := os.Mkdir(filepath.Join(dir, "service"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	heuristicsCopyFileLogs(ctx, buf, dir, "service")
+	if buf.String() != "valid logs" {
+		t.Fail()
+	}
+	buf.Reset()
+
+	// Check that service logs return the first matching file
+	if err := os.WriteFile(filepath.Join(dir, "service", "service.log"), []byte("error"), 0o444); err != nil {
+		t.Fatal(err)
+	}
+	heuristicsCopyFileLogs(ctx, buf, dir, "service")
+	if buf.String() != "valid logs" {
+		t.Fail()
+	}
+}