From 7d0ed8e9c1250bbdccb4a77e3a52d41b1da7439d Mon Sep 17 00:00:00 2001
From: Dan Gottlieb <dgottlieb@users.noreply.github.com>
Date: Thu, 13 Jun 2024 13:59:03 -0400
Subject: [PATCH] RSDK-7917: Only output `TestReconfigureParity` logs on
 failure. (#4076)

---
 logging/logging.go                  | 33 +++++++++++++++++++++++++++++
 robot/impl/resource_manager_test.go |  8 ++++++-
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/logging/logging.go b/logging/logging.go
index 8f723a2d174..aba0ef32c48 100644
--- a/logging/logging.go
+++ b/logging/logging.go
@@ -8,6 +8,7 @@ import (
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
 	"go.uber.org/zap/zaptest/observer"
+	"go.viam.com/utils"
 )
 
 var (
@@ -110,3 +111,35 @@ func NewObservedTestLogger(tb testing.TB) (Logger, *observer.ObservedLogs) {
 
 	return logger, observedLogs
 }
+
+// MemLogger stores test logs in memory. And can write them on request with `OutputLogs`.
+type MemLogger struct {
+	Logger
+
+	tb       testing.TB
+	observer *observer.ObservedLogs
+}
+
+// OutputLogs writes in-memory logs to the test object MemLogger was constructed with.
+func (memLogger *MemLogger) OutputLogs() {
+	appender := NewTestAppender(memLogger.tb)
+	for _, loggedEntry := range memLogger.observer.All() {
+		utils.UncheckedError(appender.Write(loggedEntry.Entry, loggedEntry.Context))
+	}
+}
+
+// NewInMemoryLogger creates a MemLogger that can be used to buffer test logs and output them on
+// command. This is handy if a test is noisy, but the output is useful when the test fails.
+func NewInMemoryLogger(tb testing.TB) *MemLogger {
+	observerCore, observedLogs := observer.New(zap.LevelEnablerFunc(zapcore.DebugLevel.Enabled))
+	logger := &impl{
+		name:  "",
+		level: NewAtomicLevelAt(DEBUG),
+		appenders: []Appender{
+			observerCore,
+		},
+		testHelper: tb.Helper,
+	}
+
+	return &MemLogger{logger, tb, observedLogs}
+}
diff --git a/robot/impl/resource_manager_test.go b/robot/impl/resource_manager_test.go
index a893ea5d293..d06185af91b 100644
--- a/robot/impl/resource_manager_test.go
+++ b/robot/impl/resource_manager_test.go
@@ -1838,13 +1838,19 @@ func TestReconfigureParity(t *testing.T) {
 		"data/diff_config_deps11.json",
 		"data/diff_config_deps12.json",
 	}
-	logger := logging.NewTestLogger(t)
 	ctx := context.Background()
 
 	testReconfigureParity := func(t *testing.T, initCfg, updateCfg string) {
 		name := fmt.Sprintf("%s -> %s", initCfg, updateCfg)
 		t.Run(name, func(t *testing.T) {
 			t.Parallel()
+			// Capture logs for this sub-test run. Only output the logs if the test fails.
+			logger := logging.NewInMemoryLogger(t)
+			defer func() {
+				if t.Failed() {
+					logger.OutputLogs()
+				}
+			}()
 
 			// Configuration may mutate `*config.Config`, so we read it from
 			// file each time.