[3.4] chore(e2e): backport TestNoErrorLogsDuringNormalOperations test

pkg/expect/expect.go

@@ -171,3 +171,9 @@ func (ep *ExpectProcess) Send(command string) error {
 func (ep *ExpectProcess) IsRunning() bool {
 	return ep.cmd != nil
 }
+
+func (ep *ExpectProcess) Lines() []string {
+	ep.mu.Lock()
+	defer ep.mu.Unlock()
+	return ep.lines
+}

tests/e2e/etcd_process.go

@@ -62,6 +62,7 @@ type etcdProcess interface {
 
 type logsExpect interface {
 	Expect(string) (string, error)
+	Lines() []string
 }
 
 type etcdServerProcess struct {

tests/e2e/logging_test.go

@@ -0,0 +1,75 @@
+// Copyright 2024 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package e2e
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNoErrorLogsDuringNormalOperations(t *testing.T) {
+	tests := []struct {
+		name        string
+		clusterSize int
+	}{
+		{
+			name:        "single node cluster",
+			clusterSize: 1,
+		},
+		{
+			name:        "three node cluster",
+			clusterSize: 3,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			epc, err := newEtcdProcessCluster(t,
+				&etcdProcessClusterConfig{
+					debug:       true,
+					clusterSize: tc.clusterSize,
+				},
+			)
+			require.NoError(t, err)
+			defer epc.Close()
+
+			require.Lenf(t, epc.procs, tc.clusterSize, "embedded etcd cluster process count is not as expected")
+
+			// Collect the handle of logs before closing the processes.
+			var logHandles []logsExpect
+			for i := range tc.clusterSize {
+				logHandles = append(logHandles, epc.procs[i].Logs())
+			}
+
+			time.Sleep(time.Second)
+			err = epc.Close()
+			require.NoErrorf(t, err, "closing etcd processes")
+
+			// Now that the processes are closed we can collect all log lines. This must happen after closing, else we
+			// might not get all log lines.
+			var lines []string
+			for _, h := range logHandles {
+				lines = append(lines, h.Lines()...)
+			}
+			require.NotEmptyf(t, lines, "expected at least one log line")
+
+			for _, line := range lines {
+				require.NotContainsf(t, line, "ERROR:", "error level log line found: %s", line)
+			}
+		})
+	}
+}