Remove caching in test logger setup (#661)

* Remove caching in test logger setup

* Revert "Remove caching in test logger setup"

This reverts commit e3c5349e3c.

* Don't create new logger in SetupFakeContextWithCancel

* Revert "Don't create new logger in SetupFakeContextWithCancel"

This reverts commit 2d57ccf028.

* Remove test logger cache, and leave an empty shell for ClearAll()

logging/testing/util.go

@@ -18,7 +18,6 @@ package testing
 
 import (
 	"context"
-	"sync"
 	"testing"
 
 	"go.uber.org/zap"
@@ -27,40 +26,19 @@ import (
 	"knative.dev/pkg/logging"
 )
 
-var (
-	loggers = make(map[string]*zap.SugaredLogger)
-	m       sync.Mutex
-)
-
 // TestLogger gets a logger to use in unit and end to end tests
 func TestLogger(t *testing.T) *zap.SugaredLogger {
-	m.Lock()
-	defer m.Unlock()
-
-	logger, ok := loggers[t.Name()]
-
-	if ok {
-		return logger
-	}
-
 	opts := zaptest.WrapOptions(
 		zap.AddCaller(),
 		zap.Development(),
 	)
 
-	logger = zaptest.NewLogger(t, opts).Sugar().Named(t.Name())
-	loggers[t.Name()] = logger
-
-	return logger
+	return zaptest.NewLogger(t, opts).Sugar()
 }
 
 // ClearAll removes all the testing loggers.
-// `go test -count=X` executes runs in the same process, thus the map
-// persists between the runs, but the `t` will no longer be valid and will
-// cause a panic deep inside testing code.
-func ClearAll() {
-	loggers = make(map[string]*zap.SugaredLogger)
-}
+// TODO(taragu) remove this after removing all ClearAll() calls from serving and eventing
+func ClearAll() {}
 
 // TestContextWithLogger returns a context with a logger to be used in tests
 func TestContextWithLogger(t *testing.T) context.Context {