request: move cache checker into ut

request/client.go

@@ -9,30 +9,9 @@ import (
 
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd"
-	"k8s.io/client-go/tools/metrics"
-	"k8s.io/klog/v2"
 	"k8s.io/kubectl/pkg/scheme"
 )
 
-// FIXME(weifu):
-//
-// Write UT to cover it instead of hook
-type transportCacheTracker struct{}
-
-// Increment implements k8s.io/client-go/tools/metrics.TransportCreateCallsMetric interface.
-func (t *transportCacheTracker) Increment(result string) {
-	if result != "uncacheable" {
-		klog.Fatal("unexpected use cache transport")
-	}
-	klog.V(3).Infof("transport cache: %s", result)
-}
-
-func init() {
-	metrics.Register(metrics.RegisterOpts{
-		TransportCreateCalls: &transportCacheTracker{},
-	})
-}
-
 // NewClients creates N rest.Interface.
 //
 // FIXME(weifu):

request/client_test.go

@@ -0,0 +1,35 @@
+package request
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"k8s.io/client-go/tools/metrics"
+)
+
+type transportCacheTracker struct{}
+
+// Increment implements k8s.io/client-go/tools/metrics.TransportCreateCallsMetric interface.
+func (t *transportCacheTracker) Increment(result string) {
+	if result != "uncacheable" {
+		panic(fmt.Errorf("unexpected use cache transport: %s", result))
+	}
+	fmt.Printf("transport cache: %s\n", result)
+}
+
+func init() {
+	metrics.Register(metrics.RegisterOpts{
+		TransportCreateCalls: &transportCacheTracker{},
+	})
+}
+
+func TestNewClientShouldNotPanic(t *testing.T) {
+	defer func() {
+		if r := recover(); r != nil {
+			t.Fatalf("should not reuse transport: %v", r)
+		}
+	}()
+	_, err := NewClients("testdata/dummy_nonexistent_kubeconfig.yaml", 10)
+	assert.NoError(t, err)
+}

request/testdata/dummy_nonexistent_kubeconfig.yaml

@@ -0,0 +1,21 @@
+apiVersion: v1
+clusters:
+- cluster:
+    server: https://unit-test.kperf.io
+  name: unit-test.kperf.io
+contexts:
+- context:
+    cluster: unit-test.kperf.io
+    user: testing@unit-test.kperf.io
+  name: testing@unit-test.kperf.io
+current-context: testing@unit-test.kperf.io
+kind: Config
+preferences: {}
+users:
+- name: testing@unit-test.kperf.io
+  user:
+    exec:
+      apiVersion: client.authentication.k8s.io/v1beta1
+      command: unknown
+      interactiveMode: IfAvailable
+      provideClusterInfo: false